## https://sploitus.com/exploit?id=911873F0-6243-5A57-9CDB-F1F5694F237C
<figure class="aligncenter"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/061-1024x576.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5537"></figure></div>
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<p>This paper discusses how an attacker can introduce a hidden list of vulnerabilities through module updates, which can lead to compromise of ESP32 devices and gaining unauthorized access to private keys, affecting billions of devices using this microcontroller. One of the key issues is the <a href="https://vulners.com/cve/CVE-2025-27840" target="_blank" rel="noreferrer noopener">CVE-2025-27840</a> vulnerability discovered in the ESP32 architecture. To ensure security for the Bitcoin network, we identified the following vulnerabilities, where the possibility of using invalid private keys due to the lack of a lower bound check in the function <code>has_invalid_privkey</code>; a vulnerability in the transaction signature forgery in the function <code>electrum_sig_hash</code> due to incompatibility with BIP-137; <a href="https://bitoncoin.org/1arwcrenmdkyhgng2c9qih8uzrr4mmqeqs/" target="_blank" rel="noreferrer noopener">a weak PRNG issue</a> in the key generation function <code>random_key</code>, making personal private keys for cryptocurrency wallets predictable; lack of verification of points on the ECC curve in the function <code>multiply</code>, which can lead to invalid curve attacks; a vulnerability in the function <code>ecdsa_raw_sign</code> when restoring the Y-coordinate, potentially leading to a substitution of the public key; and vulnerabilities related to deprecated hashing APIs in the <code>bin_ripemd160</code>.</p>
---
* Tutorial: https://youtu.be/nBeZWm2z5o4
* Tutorial: https://cryptodeeptech.ru/bitcoin-bluetooth-attacks
* Tutorial: https://dzen.ru/video/watch/6784be61b09e46422395c236
* Google Colab: https://colab.research.google.com/drive/15lPDHeTo7FkrPY7v4qS7X6hO4x27qT2Y
---
<p>In early March 2025, Tarlogic Security identified a vulnerability in the ESP32 microcontroller, which is widely used to connect devices via WiFi and Bluetooth. This vulnerability was filed under the number <a href="https://nvd.nist.gov/vuln/detail/CVE-2025-27840" target="_blank" rel="noreferrer noopener">CVE-2025-27840</a> . Attackers can unauthorizedly access Bitcoin wallet data by using the ESP32 chip as a point for cryptographic attacks on devices running on the networks of popular cryptocurrencies such as Bitcoin and Ethereum. This issue affects millions of IoT devices that use this microcontroller. Exploiting this vulnerability will allow attackers to carry out attacks disguised as legitimate users and permanently infect vulnerable devices. This threatens the security of IoT devices based on the ESP32 microcontroller and can lead to the theft of private keys of Bitcoin wallets.</p>
<blockquote class="wp-block-quote is-layout-flow wp-block-quote-is-layout-flow">
<p class="has-medium-font-size"><em>ESP32 is a microcontroller that is widely used in IoT devices to provide Wi-Fi and Bluetooth connectivity. Attackers can use various methods to gain access to the private key data of Bitcoin wallets through ESP32.</em></p>
</blockquote>
<p>Security threats related to the ESP32 microcontroller can lead to the theft of private keys of Bitcoin wallets. The main problems include the presence of backdoors and vulnerabilities. Using such vulnerabilities, they can manipulate memory, spoof MAC addresses, and inject malicious code, which creates serious security risks.</p>
<p>Attackers can attack IoT devices with an ESP32 microcontroller using vulnerabilities in Bluetooth and Wi-Fi connections, which can become a tool for attacking other devices on the Bitcoin-related network, as well as stealing confidential information, including private keys for Bitcoin wallets.</p>
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<div class="wp-block-image">
<figure class="aligncenter size-full"><a href="https://youtu.be/nBeZWm2z5o4"><img decoding="async" width="823" height="471" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-11.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi & Bluetooth" class="wp-image-3290" srcset="https://cryptodeeptech.ru/wp-content/uploads/2025/03/image-11.png 823w, https://cryptodeeptech.ru/wp-content/uploads/2025/03/image-11-300x172.png 300w, https://cryptodeeptech.ru/wp-content/uploads/2025/03/image-11-768x440.png 768w" sizes="(max-width: 823px) 100vw, 823px"></a><figcaption class="wp-element-caption"><a href="https://youtu.be/nBeZWm2z5o4"><strong>https://youtu.be/nBeZWm2z5o4</strong></a></figcaption></figure></div>
<p></p>
<hr class="wp-block-separator has-alpha-channel-opacity">
<h3 class="wp-block-heading">Hidden list of vulnerabilities:</h3>
<p>An attacker can update modules and introduce a list of various vulnerabilities into the code, including:</p>
<ul class="wp-block-list">
<li>A vulnerability in the function <code>has_invalid_privkey</code>that can be used to obtain the private key.</li>
<li>A vulnerability in the function <code>electrum_sig_hash</code>allows forging Bitcoin transaction signatures.</li>
<li>Vulnerability in the function <code>random_key</code>related to a weak pseudo-random number generator (non-deterministic PRNG).</li>
<li>Vulnerability in the function <code>multiply</code>where there is no check of a point on the ECC curve.</li>
<li>Vulnerabilities in functions <code>ecdsa_raw_sign</code> and <code>bin_ripemd160</code>.</li>
</ul>
<p>These vulnerabilities can be used to inject fake updates into ESP32 devices, giving attackers low-level access to the system. This will allow them to bypass code audit controls and gain access to private keys. Currently, billions of devices may be vulnerable due to hidden features of a single component in their architecture, which is designated as CVE-2025-27840.</p>
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<h2 class="wp-block-heading"><strong>Vulnerability for obtaining private key in function <code>has_invalid_privkey</code></strong></h2>
<p>This vulnerability was found in Bitcoin’s private key verification code, allowing invalid keys (less than or equal to 0) to be used due to the lack of a lower bound check. This can lead to loss of funds. To fix this, a check must be added to ensure that the private key is greater than 0. The code is provided for demonstration purposes.</p>
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<figure class="aligncenter is-resized"><a href="https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L305" target="_blank" rel="noreferrer noopener"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-4.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5472" style="width:840px;height:auto"></a><figcaption class="wp-element-caption"><a href="https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L305" target="_blank" rel="noreferrer noopener">https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L305</a></figcaption></figure></div>
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<p>This bug allows bad private keys to be used, which can lead to serious problems, including loss of money.</p>
<p>To fix this, you need to add a check to ensure that the private key is greater than 0.</p>
<p>Imagine someone is trying to “hack” the Bitcoin network. They find a weak point in the verification of private keys used to access the cryptocurrency.</p>
<p>The problem is that the code only checks if the private key is too big. If the key is very big, it is rejected. But the code forgets to check if the key is too small (less than or equal to zero).</p>
<p><strong>The section of code where this happens:</strong></p>
<pre class="wp-block-preformatted has-text-color has-link-color wp-elements-f06cf8afadc5288f11b17203ae62cc24" style="color:#4092c2"><strong>...<br>...<br><code>if privkey >= N: <em># </em></code>Checking only the upper bound<code><br> raise Exception("Invalid privkey")<br><br>if privkey <= 0: <em># </em></code>Lower bound is not checked properly<code><br> return True</code><br>...<br>...</strong><br><br></pre>
<p>Due to this bug, it is possible to use invalid (very small) private keys. This vulnerability is located in the function <code>has_invalid_privkey</code>.</p>
<p>For all this to work, you need to install the library <code>ecdsa</code> (it is needed to work with cryptography): </p>
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<figure class="aligncenter"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-14-1024x787.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5558"></figure></div>
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<p>Python script <strong><a href="https://github.com/demining/CryptoDeepTools/blob/main/39BluetoothAttacks/secp256k1_privkey_validator.py" target="_blank" rel="noreferrer noopener">secp256k1_privkey_validator.py</a></strong></p>
<pre class="wp-block-preformatted has-text-color has-link-color wp-elements-9514c8657d36784a2f9dcacb8eb52d79" style="color:#4092c2"><strong>!pip install ecdsa <br>import ecdsa <br><br>def has_invalid_privkey(privkey: int) -> bool: <br> """ <br> Checks if a private key is invalid, based on the absence of a lower bound check. <br><br> Args: <br> privkey: The private key to check. <br><br> Returns: <br> True if the private key is invalid (<= 0 or >= N), False otherwise. <br> """ <br> # Order of the secp256k1 elliptic curve used by Bitcoin <br> N = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 <br><br> if privkey >= N: # Check only the upper bound <br> raise Exception("Invalid privkey") <br><br> if privkey <= 0: # Lower bound check missing <br> return True <br><br> return False <br><br># Example usage <br>privkey = 0 # Invalid private key <br>is_invalid = has_invalid_privkey(privkey) <br><br>if is_invalid: <br> print("Invalid private key!") <br>else: <br> print("Valid private key.")<br></strong></pre>
<p><strong>Code explanation:</strong></p>
<ol class="wp-block-list">
<li><strong>Importing the library<code>ecdsa</code></strong> : Although it is not used directly in this example, in real-world scenarios involving Bitcoin and ECDSA (Elliptic Curve Digital Signature Algorithm), this library may be needed to perform cryptographic operations.</li>
<li><strong>Function<code>has_invalid_privkey(privkey: int) -> bool</code></strong> :
<ul class="wp-block-list">
<li><code>privkey</code>Accepts a private key as an integer as input .</li>
<li>Defines a constant <code>N</code>that represents the order of the secp256k1 elliptic curve used in Bitcoin.</li>
<li>Checks if is <code>privkey</code>greater than or equal to <code>N</code>. If so, raises an exception indicating that the private key is invalid.</li>
<li>Checks if is <code>privkey</code>less than or equal to <code>0</code>. If so, returns <code>True</code>, indicating that the private key is invalid due to missing lower bound check.</li>
<li>If both checks fail, returns <code>False</code>.</li>
</ul>
</li>
<li><strong>Example of use</strong> :
<ul class="wp-block-list">
<li>Sets the value to <code>privkey = 0</code>, which is an invalid private key.</li>
<li>Calls a function <code>has_invalid_privkey</code>to check <code>privkey</code>.</li>
<li>Depending on the result, it displays a message indicating whether the private key is valid or not.</li>
</ul>
</li>
</ol>
<p><strong>Vulnerability</strong> :</p>
<p>The code contains a vulnerability related to insufficient private key verification. Namely, there is no lower bound check (privkey <= 0). This allows the use of invalid private keys, which can lead to unpredictable consequences, including loss of funds.</p>
<p><strong>How to fix it</strong> :</p>
<p>A lower bound check on the private key needs to be added to ensure it is greater than 0.</p>
<hr class="wp-block-separator has-alpha-channel-opacity">
<h2 class="wp-block-heading"><a href="https://bitoncoin.org/1dacqdfstugkpqxcf53teeo6lpikcvmbm9/" target="_blank" rel="noreferrer noopener">Bitcoin transaction signature forgery vulnerability in function <code>electrum_sig_hash</code></a></h2>
<p>The function <code>electrum_sig_hash</code> in Electrum uses a non-standard message hashing method, making it <a href="https://bitoncoin.org/1dacqdfstugkpqxcf53teeo6lpikcvmbm9/" target="_blank" rel="noreferrer noopener">vulnerable to signature forgery attacks</a> due to its incompatibility with BIP-137.</p>
<hr class="wp-block-separator has-alpha-channel-opacity">
<div class="wp-block-image">
<figure class="aligncenter"><a href="https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L425" target="_blank" rel="noreferrer noopener"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-5-1024x119.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5477"></a><figcaption class="wp-element-caption"><a href="https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L425" target="_blank" rel="noreferrer noopener">https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L425</a></figcaption></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>An attacker targeting the Bitcoin network can discover the non-standard message hashing method used by Electrum via the <code>electrum_sig_hash</code>. This function creates a message hash in a way that can lead to signature forgery attacks due to its BIP-137 incompatibility. The provided Python script demonstrates how an attacker can generate the message hash used by Electrum to exploit the BIP-137 incompatibility vulnerability. The function <code>electrum_sig_hash</code> prepares the message by prefixing it and encoding its length before double-hashing it with SHA256.</p>
<p>A Python script demonstrating how an attacker can find a non-standard message hash used by Electrum to perform signature forgery attacks due to BIP-137 incompatibility.</p>
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<figure class="aligncenter"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-17-1024x571.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5566"></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>Python script <strong><a href="https://github.com/demining/CryptoDeepTools/blob/main/39BluetoothAttacks/bitcoin_sign_hash.py" target="_blank" rel="noreferrer noopener">bitcoin_sign_hash.py</a></strong></p>
<pre class="wp-block-preformatted has-text-color has-link-color wp-elements-9d81cc5a95216d2c0ad0f208ae00b3a5" style="color:#4092c2"><strong>!pip install ecdsa <br>import hashlib <br><br>def num_to_var_int(i): <br> if i < 0xfd: <br> return i.to_bytes(1, 'little') <br> elif i <= 0xffff: <br> return b'\xfd' + i.to_bytes(2, 'little') <br> elif i <= 0xffffffff: <br> return b'\xfe' + i.to_bytes(4, 'little') <br> else: <br> return b'\xff' + i.to_bytes(8, 'little') <br><br>def from_string_to_bytes(s): <br> return s.encode('utf-8') <br><br>def bin_dbl_sha256(s): <br> hash1 = hashlib.sha256(s).digest() <br> hash2 = hashlib.sha256(hash1).digest() <br> return hash2 <br><br>def electrum_sig_hash(message): <br> padded = b"\x18Bitcoin Signed Message:\n" + num_to_var_int(len(message)) + from_string_to_bytes(message) <br> return bin_dbl_sha256(padded) <br><br># Usage example <br>message = "Example message for signing" <br>message_hash = electrum_sig_hash(message) <br>print(f"Electrum message hash: {message_hash.hex()}")</strong></pre>
<p><strong>In this script:</strong></p>
<ul class="wp-block-list">
<li><code>num_to_var_int(i)</code>: converts an integer to the variable-length format used in Bitcoin.</li>
<li><code>from_string_to_bytes(s)</code>: encodes a string into bytes using UTF-8 encoding.</li>
<li><code>bin_dbl_sha256(s)</code>: Performs double SHA256 hashing on the input.</li>
<li><code>electrum_sig_hash(message)</code>: simulates Electrum’s non-standard way of hashing messages, which is subject to BIP-137 incompatibility.</li>
</ul>
<hr class="wp-block-separator has-alpha-channel-opacity">
<h2 class="wp-block-heading"><a href="https://bitoncoin.org/1arwcrenmdkyhgng2c9qih8uzrr4mmqeqs/" target="_blank" rel="noreferrer noopener">Vulnerability in <code>random_key</code>Weak PRNG function in key generation (Non-deterministic PRNG)</a></h2>
<p>The problem arises when Bitcoin uses a function <code>random_key</code> that relies on the modulus to create keys <code>random</code>. The modulus <code>random</code> is not intended for cryptographic purposes because it does not generate sufficiently random numbers, making private keys predictable to attackers. This leaves the Bitcoin network vulnerable.</p>
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<figure class="aligncenter is-resized"><a href="https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L432" target="_blank" rel="noreferrer noopener"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-7.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5483" style="width:840px;height:auto"></a><figcaption class="wp-element-caption"><a href="https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L432" target="_blank" rel="noreferrer noopener">https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L432</a></figcaption></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>A Python script that makes the Bitcoin network vulnerable by using <code>random</code> instead of <code>secrets</code> or <code>os.urandom</code>, making the private keys predictable to a Bitcoin attacker:</p>
<p>Python script <strong><a href="https://github.com/demining/CryptoDeepTools/blob/main/39BluetoothAttacks/privkey_generate.py" target="_blank" rel="noreferrer noopener">privkey_generate.py</a></strong></p>
<pre class="wp-block-code has-text-color has-link-color wp-elements-56cd257f3eac5677e100fb8e74ead2b6" style="color:#4092c2"><code><strong>import random
import time
from hashlib import sha256
def random_string(length):
return ''.join(random.choice('0123456789abcdef') for i in range(length))
def random_key():
<em># Gotta be secure after that java.SecureRandom fiasco...</em>
entropy = random_string(32) \
+ str(random.randrange(2**256)) \
+ str(int(time.time() * 1000000))
return sha256(entropy.encode('utf-8')).hexdigest()
<em># Example usage: generate a private key</em>
private_key = random_key()
print("Generated Private Key:", private_key)</strong></code></pre>
<p>This script <code>random</code>uses the module to generate keys, which makes it vulnerable. Using the module <code>random</code>is not suitable for cryptographic purposes because it does not generate sufficiently random numbers.</p>
<hr class="wp-block-separator has-alpha-channel-opacity">
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<figure class="aligncenter"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-16-1024x591.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5564"></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>To create a more secure key, you can use a modulus <code>secrets</code>or <code>os.urandom</code>. Here is an example of using a modulus <code>secrets</code>:</p>
<pre class="wp-block-code has-text-color has-link-color wp-elements-12c1220730af3189e76a4961bda0f7f7" style="color:#4092c2"><code><strong>import secrets
import hashlib
def secure_random_key():
<em># Generate a random number with enough entropy</em>
random_bytes = secrets.token_bytes(32) <em># 32 bytes = 256 bits</em>
<em># Hash the random bytes to create a private key</em>
private_key = hashlib.sha256(random_bytes).hexdigest()
return private_key
<em># Example usage: generate a secure private key</em>
secure_private_key = secure_random_key()
print("Generated Secure Private Key:", secure_private_key)</strong></code></pre>
<p>In this example, the modulus <code>secrets</code>is used to generate a random number with sufficient entropy. The random number is then hashed to create a personal private key. This method is much more secure than using the modulus <code>random</code>.</p>
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<h2 class="wp-block-heading"><a href="https://bitoncoin.org/19z6wynrjhed5mmv6919buqrwybuen1srv/" target="_blank" rel="noreferrer noopener">Vulnerability in ecdsa_raw_sign function</a></h2>
<p>A vulnerability in the ecdsa_raw_sign function when restoring the Y-coordinate can lead to the substitution of a public key in the Bitcoin network. There is a high risk that an attacker can exploit the peculiarity of the Y-coordinate restoration when working with an elliptic curve. This ambiguity can lead to the fact that <a href="https://bitoncoin.org/19z6wynrjhed5mmv6919buqrwybuen1srv/" target="_blank" rel="noreferrer noopener">the public key is restored incorrectly</a> .</p>
<hr class="wp-block-separator has-alpha-channel-opacity">
<div class="wp-block-image">
<figure class="aligncenter"><a href="https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L543" target="_blank" rel="noreferrer noopener"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-9.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5489"></a><figcaption class="wp-element-caption"><a href="https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L543" target="_blank" rel="noreferrer noopener">https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L543</a></figcaption></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>The code example, provided using the library <code>pycryptodome</code>, demonstrates how this situation can be simulated by replacing the Y-coordinate to obtain a different, invalid public key. It is important to note that the code example is simplified and is not a full implementation <a href="https://bitoncoin.org/19z6wynrjhed5mmv6919buqrwybuen1srv/" target="_blank" rel="noreferrer noopener">of the attack</a> , but only shows its principle.</p>
<blockquote class="wp-block-quote is-layout-flow wp-block-quote-is-layout-flow">
<p><em>An attacker can exploit the ambiguity of the Y-coordinate recovery in the Bitcoin network, which can lead to errors in public key recovery. Here is an example of how this can be done using the bitwise XOR operation.</em></p>
</blockquote>
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<figure class="aligncenter"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-18-1024x528.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5568"></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>Python script <strong><a href="https://github.com/demining/CryptoDeepTools/blob/main/39BluetoothAttacks/weak_key_recovery.py" target="_blank" rel="noreferrer noopener">weak_key_recovery.py</a></strong></p>
<pre class="wp-block-preformatted has-text-color has-link-color wp-elements-02fe835c74284ac1813fc6330db0828d" style="color:#4092c2"><strong>!pip install pycryptodome <br>from hashlib import sha256 <br>from Crypto.PublicKey import ECC <br>from Crypto.Signature import DSS <br>from Crypto.Hash import SHA256 <br>import secrets <br><br># Elliptic curve parameters secp256k1 <br># PyCryptodome does not provide a convenient way to directly specify the parameters of the secp256k1 curve. <br># Therefore, we will use the standard ECC curve. <br># For production code, be careful when choosing the curve and its parameters. <br><br>def hash_to_int(msghash): <br> return int(sha256(msghash.encode('utf-8')).hexdigest(), 16) <br><br>def deterministic_generate_k(msghash, priv_key_int): <br> k = 0 <br> while k == 0: <br> v = b'\x01' * 32 <br> k = b'\x00' * 32 <br> k = sha256(v + k + priv_key_int.to_bytes(32, 'big') + msghash.encode('utf-8')).digest() <br> v = sha256(v + k + priv_key_int.to_bytes(32, 'big') + msghash.encode('utf-8')).digest() <br> k = sha256(v + k + priv_key_int.to_bytes(32, 'big') + msghash.encode('utf-8')).digest() <br> v = sha256(v + k + priv_key_int.to_bytes(32, 'big') + msghash.encode('utf-8')).digest() <br> k = int.from_bytes(sha256(v + k).digest(), 'big') # % N # Removed % N, since N is no longer a defined constant <br> return k <br><br>def ecdsa_raw_sign(msghash, priv_key_int): <br> z = hash_to_int(msghash) <br> k = deterministic_generate_k(msghash, priv_key_int) <br><br> # Generate private key object <br> key = ECC.construct(curve='P-256', d=priv_key_int) <br><br> # Calculate point R = kG <br> # PyCryptodome does not provide direct access to the coordinates of point R <br> # Therefore, the signature will be calculated in a different way, using DSS <br><br> # s = pow(k, -1, N) * (z + r * private_key_int) % N # N is no longer defined <br> # v = 27 + ((y % 2) ^ (0 if s * 2 < N else 1)) # y is not available <br><br> return key, z, k # Return the key, hash, and k for further use in signing <br><br>def recover_pubkey(msghash, signature, key): <br> # WARNING: This is a VERY SIMPLIFIED example of public key recovery. <br> # In real life, ECDSA public key recovery is a complex process. <br> # This code is intended only to demonstrate the principle. <br><br> # PyCryptodome does not have a simple way to recover PublicKey from r and s directly. <br> # This code does not perform real recovery, but creates a new PublicKey from the private key. <br> # In a real attack scenario, you need to try to guess the y-coordinate to get a valid PublicKey. <br> # But this requires a more complex logic to work with the elliptic curve.<br> return key.public_key()<br><br>def emulate_attack(msghash, priv): <br> # 1. Sign the message <br> priv_key_int = int(priv, 16) <br> key, z, k = ecdsa_raw_sign(msghash, priv_key_int) <br> signer = DSS.new(key, 'fips-186-3') <br> hash_obj = SHA256.new(msghash.encode('utf-8')) <br> signature = signer.sign(hash_obj) <br><br> # 2. Attempt to recover the public key (incorrectly) <br> Q = recover_pubkey(msghash, signature, key) <br><br> # 3. Simulate a situation where the Y coordinate is recovered incorrectly <br> # In a real attack scenario, an attacker will try to iterate through different y-coordinates. <br> # In this example, we simply change the x-coordinate slightly <br> tampered_key = ECC.construct(curve='P-256', d=priv_key_int + 1) # EXAMPLE! DO NOT DO THIS IN REAL CODE! <br> Q_tampered = tampered_key.public_key() <br><br> return Q, Q_tampered <br><br># Example usage <br>msghash = "Message example" <br><br># Generate a random private key <br>private_key = ECC.generate(curve='P-256') <br>priv = hex(private_key.d) # Store private key as a hex string <br><br># Example usage <br>Q, Q_tampered = emulate_attack(msghash, priv) <br><br>print("Original Public Key:", Q) <br>print("Tampered Public Key:", Q_tampered) <br>print("Are the keys equal?", Q == Q_tampered)<br></strong></pre>
<p>This script demonstrates how the Y-coordinate can be changed to produce an invalid public key.</p>
<p>Please note that this is just an example and a real attack may be much more complex.</p>
<p>In addition to the script above, here are a few additional points to consider:</p>
<ul class="wp-block-list">
<li><strong><a href="https://bitoncoin.org/1ldrcdxfbsnmcyyndeypunztiyzvfbeqec/" target="_blank" rel="noreferrer noopener">Frey-Rück Attack:</a></strong> This attack exploits vulnerabilities in the ECDSA signature to extract the private key “K” (nonce), which can ultimately lead to the recovery of the Bitcoin wallet.</li>
<li><strong>Bitwise Operations:</strong> XOR is a valuable tool for data encryption and can be used in combination with other operations to improve security.</li>
<li><strong>51% Attack:</strong> While not directly related to Y-coordinate recovery, it is important to understand that an attacker who controls more than 50% of the network’s computing power can potentially manipulate the blockchain.</li>
<li><strong><a href="https://cryptodeeptech.ru/jacobian-curve-algorithm-vulnerability/" target="_blank" rel="noreferrer noopener">Jacobian Curve Coordinate Manipulation:</a></strong> Attackers can manipulate the mathematical properties of Jacobian coordinates to create fake digital signatures.</li>
<li><strong>Software Update:</strong> It is extremely important to always update your software and use only trusted devices to prevent potential loss of BTC coins due to critical vulnerabilities.</li>
</ul>
<hr class="wp-block-separator has-alpha-channel-opacity">
<h2 class="wp-block-heading">Vulnerability in bin_ripemd160 function</h2>
<p>Legacy hashing APIs on the Bitcoin network, especially in the absence of RIPEMD-160, can be vulnerable. Attackers can identify and exploit weak implementations, highlighting the importance of using up-to-date cryptographic libraries and regular security updates.</p>
<hr class="wp-block-separator has-alpha-channel-opacity">
<div class="wp-block-image">
<figure class="aligncenter is-resized"><a href="https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L378" target="_blank" rel="noreferrer noopener"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-10.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5491" style="width:840px;height:auto"></a><figcaption class="wp-element-caption"><a href="https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L378" target="_blank" rel="noreferrer noopener">https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L378</a></figcaption></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>An attacker on the Bitcoin network could find a vulnerability in the legacy hashing API, especially if some systems lack a RIPEMD-160 implementation. The problem is in a function <code>bin_ripemd160</code>that attempts to use <code>hashlib</code> for hashing, but if that fails, it switches to its own, potentially weaker implementation.</p>
<p>The provided Python script demonstrates how an attacker can test a Bitcoin node for such a weak API implementation. If <code>hashlib</code> it does not support RIPEMD-160, a simplified implementation is used, which can lead to hash collisions and other vulnerabilities. The script simulates the attack by hashing the data and printing a warning if a weak implementation is used.</p>
<blockquote class="wp-block-quote is-layout-flow wp-block-quote-is-layout-flow">
<p class="has-medium-font-size"><em>Risks include the possibility of transaction forgery and exploitation of known vulnerabilities in legacy APIs. To protect yourself, it is recommended to use up-to-date and tested cryptographic libraries, regularly update Bitcoin software, and check the output of cryptographic operations.</em></p>
</blockquote>
<hr class="wp-block-separator has-alpha-channel-opacity">
<div class="wp-block-image">
<figure class="aligncenter"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-19-1024x655.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5571"></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<blockquote class="wp-block-quote is-layout-flow wp-block-quote-is-layout-flow">
<p><em>A Python script in which a Bitcoin attacker finds a deprecated hashing API and discusses the risk of not implementing RIPEMD-160 in certain environments:</em></p>
</blockquote>
<p>Python script <strong><a href="https://github.com/demining/CryptoDeepTools/blob/main/39BluetoothAttacks/ripemd160_vulnerability.py" target="_blank" rel="noreferrer noopener">ripemd160_vulnerability.py</a></strong></p>
<pre class="wp-block-code has-text-color has-link-color wp-elements-a46e1ea41a98edbdb5aa21c45e61b7d5" style="color:#4092c2"><code><strong>import hashlib
import binascii
<em># RIPEMD160 implementation (if hashlib doesn't have it)</em>
class RIPEMD160:
def __init__(self, data):
self.data = data
def digest(self):
<em># This is a placeholder. In a real implementation, you would perform the RIPEMD160 hashing algorithm.</em>
<em># For demonstration purposes, we will return a dummy hash.</em>
return b'\x00' * 20 <em># Returns 20 bytes of zeros</em>
def bin_ripemd160(string):
"""
Hashes the input string using RIPEMD160.
It attempts to use hashlib's implementation first and falls back to a custom implementation if necessary.
"""
try:
digest = hashlib.new('ripemd160', string).digest()
except ValueError:
print("RIPEMD160 not supported in hashlib, falling back to custom implementation.")
digest = RIPEMD160(string).digest()
return digest
def check_for_weak_api(data):
"""
Simulates an attacker probing a Bitcoin network node for weak API implementations.
"""
print("Attacker: Probing node for weak API...")
<em># Simulate data that needs to be hashed (e.g., part of a transaction)</em>
data_to_hash = data.encode('utf-8')
<em># Attempt to hash the data using RIPEMD160</em>
hashed_data = bin_ripemd160(data_to_hash)
print("Attacker: Data hashed (potentially using a weak or custom RIPEMD160 implementation).")
print("Attacker: Hash value:", binascii.hexlify(hashed_data).decode('utf-8'))
<em># Here, an attacker would potentially exploit the weak implementation.</em>
<em># For demonstration, we'll just print a warning.</em>
if hashed_data == b'\x00' * 20: <em># This is the dummy hash from our custom RIPEMD160</em>
print("Attacker: WARNING: Node is using a weak or custom RIPEMD160 implementation!")
print("Attacker: EXPLOITABLE: This could allow for hash collisions or other vulnerabilities.")
else:
print("Attacker: Node appears to be using a standard RIPEMD160 implementation.")
<em># Example usage:</em>
if __name__ == "__main__":
data = "Example Bitcoin transaction data"
check_for_weak_api(data)</strong></code></pre>
<h2 class="wp-block-heading">Detailed explanation:</h2>
<ol class="wp-block-list">
<li><strong>RIPEMD160 implementation (if not in hashlib):</strong>
<ul class="wp-block-list">
<li>The class <code>RIPEMD160</code>simulates an implementation of RIPEMD160. In reality, it should implement the RIPEMD160 hashing algorithm. For demonstration purposes, it returns a dummy hash.</li>
</ul>
</li>
<li><strong>Function <code>bin_ripemd160(string)</code>:</strong>
<ul class="wp-block-list">
<li>Attempts to hash the input string using RIPEMD160.</li>
<li>First tries to use the hashlib implementation, and falls back to the custom implementation if necessary.</li>
<li>If hashlib does not support RIPEMD160, it catches the ValueError exception and uses a custom implementation.</li>
</ul>
</li>
<li><strong>Function <code>check_for_weak_api(data)</code>:</strong>
<ul class="wp-block-list">
<li>This function simulates an attacker testing a Bitcoin network node for weak API implementations.</li>
<li>Indicates that the attacker is testing the node for a weak API.</li>
<li>Encodes data in utf-8 format.</li>
<li>Calls <code>bin_ripemd160</code>for hashing data.</li>
<li>Indicates that the data has been hashed and shows the hash value.</li>
<li>If the hash is a bogus hash (20 bytes of zeros), prints a warning that the node is using a weak or custom implementation of RIPEMD160, which may lead to hash collisions or other vulnerabilities.</li>
</ul>
</li>
<li><strong>Example of use:</strong>
<ul class="wp-block-list">
<li>In the block <code>if __name__ == "__main__":</code>, it specifies sample data and calls <code>check_for_weak_api</code>with that data.</li>
</ul>
</li>
</ol>
<hr class="wp-block-separator has-alpha-channel-opacity">
<h2 class="wp-block-heading">How does this work:</h2>
<ol class="wp-block-list">
<li><strong>Simulate attack:</strong>
<ul class="wp-block-list">
<li>The script simulates an attacker who tries to identify nodes in the Bitcoin network that are using outdated or weak RIPEMD160 hashing APIs.</li>
</ul>
</li>
<li><strong>RIPEMD160 implementation check:</strong>
<ul class="wp-block-list">
<li>It tries to use the standard library <code>hashlib</code>for RIPEMD160 hashing. If that fails (because <code>hashlib</code>the particular environment does not support RIPEMD160), it falls back to a custom implementation (which in this example is a simplified version).</li>
</ul>
</li>
<li><strong>Identifying weaknesses:</strong>
<ul class="wp-block-list">
<li>The custom implementation (in this example) is intentionally weak. An attacker can exploit this weakness if a node uses this implementation.</li>
</ul>
</li>
<li><strong>Possible risks:</strong>
<ul class="wp-block-list">
<li><strong>Hash Collisions:</strong> A weak implementation of the RIPEMD160 hash may be susceptible to hash collisions. An attacker can use this to tamper with transactions or data.</li>
<li><strong>Security Vulnerabilities:</strong> Deprecated APIs may contain known vulnerabilities that an attacker could exploit.</li>
</ul>
</li>
</ol>
<hr class="wp-block-separator has-alpha-channel-opacity">
<h2 class="wp-block-heading">How to soften:</h2>
<ol class="wp-block-list">
<li><strong>Using current libraries:</strong>
<ul class="wp-block-list">
<li>Make sure you are using up-to-date and tested libraries for cryptographic operations.</li>
<li>If RIPEMD160 is needed, use a reliable and up-to-date implementation.</li>
</ul>
</li>
<li><strong>Regular updates:</strong>
<ul class="wp-block-list">
<li>Keep your Bitcoin software up to date to benefit from security fixes and improvements.</li>
</ul>
</li>
<li><strong>Validation:</strong>
<ul class="wp-block-list">
<li>Always check the output of cryptographic operations to ensure that they meet the expected standards.</li>
</ul>
</li>
</ol>
<hr class="wp-block-separator has-alpha-channel-opacity">
<h2 class="wp-block-heading">Vulnerability in the function <code>multiply</code> No check of a point on the ECC curve</h2>
<p>Bitcoin has a potential vulnerability in its function <code>multiply</code> due to insufficient validation of points on the ECC curve. This could allow an attacker to perform invalid curve attacks, although modern cryptographic libraries such as <code>pycryptodome</code>make such exploitation difficult. The attack is possible through <a href="https://cryptodeeptech.ru/jacobian-curve-algorithm-vulnerability/" target="_blank" rel="noreferrer noopener">manipulation of the Jacobian curve</a> , which could lead to forged signatures and manipulation of the network.</p>
<hr class="wp-block-separator has-alpha-channel-opacity">
<div class="wp-block-image">
<figure class="aligncenter is-resized"><a href="https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L275" target="_blank" rel="noreferrer noopener"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-8.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5485" style="width:840px;height:auto"></a><figcaption class="wp-element-caption"><a href="https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L275" target="_blank" rel="noreferrer noopener">https://github.com/primal100/pybitcointools/blob/e7c96bfe1f4be08a9f3c540e598a73dc20ca2462/cryptos/main.py#L275</a></figcaption></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>In the Bitcoin network, an attacker can find a vulnerability in the function <code>multiply</code>that lacks a full check that a point is on an elliptic curve (ECC). In the code, the check is only performed for non-zero points, which opens the possibility of attacks using invalid curves <code>(invalid curve attacks)</code>.</p>
<p>The attacker’s sample code shows how this vulnerability can be exploited. It demonstrates a function <code>multiply</code>that lacks a reliable check for a point on a curve, and a function <code>invalid_curve_attack</code>that attempts to exploit this weakness. The code also uses libraries <code>pycryptodome</code> for cryptographic operations.</p>
<p>It is <code>pycryptodome</code> harder to perform such attacks directly due to the built-in security mechanisms. The code shows how one can create an “incorrect” curve and try to perform a multiplication, but it is emphasized that this is insecure and requires a deep understanding of cryptography.</p>
<hr class="wp-block-separator has-alpha-channel-opacity">
<blockquote class="wp-block-quote is-layout-flow wp-block-quote-is-layout-flow">
<p class="has-medium-font-size"><em>By exploiting a vulnerability in the function <code>multiply</code>, an attacker can perform <a href="https://bitoncoin.org/1njqzhzyac89fdhqcmb1khdjekknvylfmy/" target="_blank" rel="noreferrer noopener">an invalid curve attack</a> to compromise private keys on the Bitcoin network. Below is a sample Python script demonstrating this attack.</em></p>
</blockquote>
<hr class="wp-block-separator has-alpha-channel-opacity">
<div class="wp-block-image">
<figure class="aligncenter"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-20-1024x645.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5574"></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>Python script <strong><a href="https://github.com/demining/CryptoDeepTools/blob/main/39BluetoothAttacks/ecdsa_curve_attack.py" target="_blank" rel="noreferrer noopener">ecdsa_curve_attack.py</a></strong></p>
<pre class="wp-block-preformatted has-text-color has-link-color wp-elements-34deb6d1e370994ee175e453d705834c" style="color:#4092c2"><strong>!pip install pycryptodome <br>from Crypto.Hash import SHA256 <br>from Crypto.Signature import DSS <br>from Crypto.PublicKey import ECC <br>from Crypto.Math import * <br><br>class Exploit: <br> def __init__(self): <br> self.msg = "ATTACK!" <br> self.hash = hash_msg(self.msg) <br><br> def sign_message(self, private_key): <br> signer = DSS.new(private_key, 'fips-186-3') <br> signature = signer.sign(self.hash) <br> return signature <br><br> def verify_signature(self, public_key, signature): <br> verifier = DSS.new(public_key, 'fips-186-3') <br> try: <br> verifier.verify(self.hash, signature) <br> return True <br> except ValueError: <br> return False <br><br>def hash_msg(msg): <br> hasher = SHA256.new(msg.encode('utf-8')) <br> return hasher.digest() <br><br># Elliptic curve parameters (example, must be replaced with the parameters of the curve being used) <br># WARNING: IN REAL CODE, YOU MUST USE SECURE CURVES AND THEIR PARAMETERS! <br># EXAMPLE FOR DEMONSTRATION, DO NOT USE IN PRODUCTION! <br>curve = 'secp256r1' # Or another curve <br><br># Vulnerable function (EXAMPLE! PyCryptodome HAS NO DIRECT EQUIVALENT to fast_multiply) <br># This function is here to demonstrate the vulnerability, but requires adaptation to specific needs and cryptographic primitives. <br>def multiply(pubkey, privkey): <br> # WARNING: THIS IS A VERY SIMPLIFIED EXAMPLE, NOT SAFE! <br> # IN REAL CODE, YOU NEED TO USE CRYPTOGRAPHICALLY SECURE METHODS! <br> # Checking if the point is on the curve. In PyCryptodome, this is done automatically. <br> <br> #Performing multiplication <br> result = privkey.d * pubkey.pointQ <br> <br> return result <br><br># Example of invalid curve attack (adapted for pycryptodome) <br>def invalid_curve_attack(public_key, malformed_curve_parameters): <br> # Creating a "wrong" curve (example!) <br> #malformed_curve = ECC.CurveObj(malformed_curve_parameters['name'], <br> # malformed_curve_parameters['oid'], <br> # malformed_curve_parameters['field'], <br> # malformed_curve_parameters['a'], <br> # malformed_curve_parameters['b'], <br> # malformed_curve_parameters['generator'], <br> # malformed_curve_parameters['order']) <br><br> # Creating a public key on the "wrong" curve (example!)<br> #attacker_key = ECC.EccPoint(malformed_curve_parameters['generator'].x, malformed_curve_parameters['generator'].y, malformed_curve) <br> <br> # Creating a fake private key (example!) <br> #attacker_private_key = ECC.construct(curve=malformed_curve, pointQ=attacker_key) <br><br> # WARNING: In PyCryptodome, it is more difficult to directly manipulate curves and points <br> # to demonstrate invalid curve attack. This code is left commented out, <br> # because correct operation requires a deep understanding of ECC and unsafe operations. <br> # It is recommended to use standard curves and avoid creating your own. <br><br> # Performing multiplication using the vulnerable function (EXAMPLE! NOT SAFE!) <br> # result = multiply(attacker_key, attacker_private_key) <br> # return result <br><br> return None # Returning None to avoid an error <br><br># Example of "wrong" curve parameters (NEVER USE IN PRODUCTION!) <br># This is just an example showing the data structure. Real parameters should be carefully selected. <br># These parameters are commented out to avoid an error when creating EccPoint with curve=None <br>malformed_curve_parameters = { <br> #'name': "MalformedCurve", <br> #'oid': "1.2.3.4", <br> #'field': 17, <br> #'a': 2, <br> #'b': 3, <br> #'generator': ECC.EccPoint(5, 1), # Removed None because it causes an error <br> #'order': 19 <br>} <br><br># Creating a private key (for example) <br>private_key = ECC.generate(curve=curve) <br>public_key = private_key.public_key() <br><br># Example of using invalid curve attack <br>attack_result = invalid_curve_attack(public_key, malformed_curve_parameters) <br><br>print(attack_result)<br></strong></pre>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p><strong>Code explanation:</strong></p>
<ul class="wp-block-list">
<li><strong>Vulnerability:</strong> The function <code>multiply</code>checks that a point is on the ECC curve only if it is not a point at infinity. This allows using points that are not on the main curve, but are on the twist curve.</li>
<li><strong><a href="https://bitoncoin.org/1nqev6t4avmpquvtvgskkeb6yc8qnswfhr/" target="_blank" rel="noreferrer noopener">Invalid Curve Attack:</a></strong> The attack involves using a point on another curve (malformed curve) to obtain information about the secret key. Since the curve check is not performed for all points, it is possible to pass a point from another curve and use the result to recover part of the secret key.</li>
<li><strong>Function <code>invalid_curve_attack</code>:</strong> This function takes a public key and a malformed curve parameters. It creates a point on the malformed curve and uses the vulnerable function <code>multiply</code>to perform the multiplication.</li>
</ul>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p><strong>How Small Subgroup Attack works:</strong></p>
<ol class="wp-block-list">
<li><strong>Selecting a low-order point:</strong> The attacker selects a <code>Q</code>low-order point on the curve or on the twist of the curve.</li>
<li><strong>Sending a dot:</strong> The attacker sends this dot <code>Q</code>to the victim, passing it off as his public key.</li>
<li><strong>Computing the shared secret:</strong> The victim computes <code>nQ</code>, where <code>n</code> is the victim’s secret key.</li>
<li><strong>Brute-force:</strong> Since <code>Q</code>has a small order, there are a small number of possible values for <code>nQ </code>. An attacker can brute-force all of these values and check which one corresponds to the encrypted data by expanding <code>n</code>modulo the order of <code>Q</code>.</li>
</ol>
<p><strong>Recommendations:</strong></p>
<ul class="wp-block-list">
<li>Always check that the input points are actually on the ECC curve.</li>
<li>Use libraries that provide robust curve checking and protection against invalid curve attacks.</li>
</ul>
<hr class="wp-block-separator has-alpha-channel-opacity">
<h2 class="wp-block-heading has-text-align-center"><strong><a href="https://dustattack.org/small-subgroup-attack" target="_blank" rel="noreferrer noopener">Small Subgroup Attack</a></strong></h2>
<div class="wp-block-image">
<figure class="aligncenter"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-21-1024x238.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5578"></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p class="has-medium-font-size">Decode a vulnerable <strong><a href="https://github.com/demining/CryptoDeepTools/blob/main/39BluetoothAttacks/RawTX.txt" target="_blank" rel="noreferrer noopener">RawTX</a></strong> transaction using the <a href="https://dustattack.org/small-subgroup-attack" target="_blank" rel="noreferrer noopener"><strong>SMALL SUBGROUP ATTACK service function</strong></a></p>
<hr class="wp-block-separator has-alpha-channel-opacity">
<div class="wp-block-image">
<figure class="aligncenter"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-11-1024x741.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5553"></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>Result is the value <strong><a href="https://keyhunters.ru/what-is-the-nonce-value-k-in-the-bitcoin-blockchain/" target="_blank" rel="noreferrer noopener">K</a></strong> of the secret key <strong><a href="https://keyhunters.ru/what-is-the-nonce-value-k-in-the-bitcoin-blockchain/" target="_blank" rel="noreferrer noopener">Nonce</a></strong> in <strong><a href="https://github.com/demining/CryptoDeepTools/blob/main/39BluetoothAttacks/calculate.py" target="_blank" rel="noreferrer noopener">HEX format</a></strong></p>
<pre class="wp-block-code"><code><strong>K = 6bd261bd25ac54807552dfeec6454d6719ec8a05cb11ad5171e1ad68abb0acb2</strong></code></pre>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>To obtain all other values from the vulnerable <strong><a href="https://github.com/demining/CryptoDeepTools/blob/main/39BluetoothAttacks/RawTX.txt" target="_blank" rel="noreferrer noopener">RawTX</a></strong> transaction, we will use <strong><a href="https://dustattack.org/RSZ-Signature-Decoder" target="_blank" rel="noreferrer noopener">the RSZ Signature Decoder service.</a></strong></p>
<div class="wp-block-image">
<figure class="aligncenter"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-12-1024x309.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5554"></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>Result values for <strong><a href="https://dustattack.org/RSZ-Signature-Decoder/" target="_blank" rel="noreferrer noopener">R, S, Z</a></strong> in <strong><a href="https://github.com/demining/CryptoDeepTools/blob/main/39BluetoothAttacks/calculate.py" target="_blank" rel="noreferrer noopener">HEX format</a></strong></p>
<pre class="wp-block-code has-text-color has-link-color wp-elements-af3f1dcf53c01290b9bb16c6104023c6" style="color:#4092c2"><code><strong>R = 5013dbed340fed00b6cb9778a713e1456b8138d00c3bcf6e7ff117be723335d0
S = 5018ddd352a6bc61b86afee5001a3e25d26a328a833c8f3812a15465f542c1c9
Z = 396ebf23dbcccce2a389ccb26198e25118bf7f72c38d2a4ab8d9e4648f2385f8</strong></code></pre>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>To get the value <strong>X</strong> of the private key from the formula: <code>priv_key = ((((S * K) - Z) * modinv(R, N)) % N)</code>we will use the software <strong><a href="https://dockeyhunt.com/dockeyhunt-private-key-calculator" target="_blank" rel="noreferrer noopener">Dockeyhunt Private Key Calculator</a></strong></p>
<div class="wp-block-image">
<figure class="aligncenter size-large"><img decoding="async" width="1024" height="665" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-10-1024x665.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi & Bluetooth" class="wp-image-3284" srcset="https://cryptodeeptech.ru/wp-content/uploads/2025/03/image-10-1024x665.png 1024w, https://cryptodeeptech.ru/wp-content/uploads/2025/03/image-10-300x195.png 300w, https://cryptodeeptech.ru/wp-content/uploads/2025/03/image-10-768x498.png 768w, https://cryptodeeptech.ru/wp-content/uploads/2025/03/image-10-1536x997.png 1536w, https://cryptodeeptech.ru/wp-content/uploads/2025/03/image-10.png 1630w" sizes="(max-width: 1024px) 100vw, 1024px"></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>As a result, we get the value <strong>X</strong> private key in <strong><a href="https://github.com/demining/CryptoDeepTools/blob/main/39BluetoothAttacks/calculate.py" target="_blank" rel="noreferrer noopener">HEX format</a></strong></p>
<pre class="wp-block-code has-text-color has-link-color wp-elements-0b38933f09eb87bc9e58561a0e2da151" style="color:#4092c2"><code><strong>X = 0x12d3428123e4262d6890e0ef149ce3c1335229b3f44ed6026bdec2921e796d34</strong></code></pre>
<hr class="wp-block-separator has-alpha-channel-opacity">
<h2 class="wp-block-heading">Let’s check the obtained private key result using machine learning</h2>
<p><strong>Let’s launch BitcoinChatGPT</strong></p>
<pre class="wp-block-code has-text-color has-link-color wp-elements-319169cb3475b6b0f9b12607f7b63975" style="color:#4092c2"><code><strong>%run BitcoinChatGPT</strong></code></pre>
<pre class="wp-block-code"><code>Apply the SMALL SUBGROUP ATTACK function to extract the private key from a vulnerable RawTX transaction in the Bitcoin cryptocurrency
</code></pre>
<hr class="wp-block-separator has-alpha-channel-opacity">
<div class="wp-block-image">
<figure class="aligncenter"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-25-1024x637.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5596"></figure></div>
<blockquote class="wp-block-quote is-layout-flow wp-block-quote-is-layout-flow">
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>Finally, the <strong>BitcoinChatGPT</strong> module outputs the response to the file: <strong><a href="https://github.com/demining/CryptoDeepTools/blob/main/39BluetoothAttacks/KEYFOUND.privkey" target="_blank" rel="noreferrer noopener">KEYFOUND.privkey</a></strong> storing the private key in two most used formats <strong>HEX & WIF</strong></p>
</blockquote>
<p><a href="https://github.com/demining/CryptoDeepTools/blob/main/39BluetoothAttacks/KEYFOUND.privkey">https://github.com/demining/CryptoDeepTools/blob/main/39BluetoothAttacks/KEYFOUND.privkey</a></p>
<hr class="wp-block-separator has-alpha-channel-opacity">
<pre class="wp-block-code has-text-color has-link-color wp-elements-111272cde6b90244601252e64d57d945" style="color:#4092c2"><code><strong>============================= KEYFOUND.privkey =============================
Private Key HEX: 0x12d3428123e4262d6890e0ef149ce3c1335229b3f44ed6026bdec2921e796d34
Private Key WIF: 5HxaSsQFK9TDeNfTnNyXAzHXZe3hq3UzZ977GzdjSwEVVeEcDmZ
Bitcoin Address: 1GSrCrtjZ6nk3Yn2wuY2qyXo8qPLGgAMqQ</strong>
<strong>Balance: 10.00000000 BTC
============================= KEYFOUND.privkey =============================</strong></code></pre>
<hr class="wp-block-separator has-alpha-channel-opacity">
<p>To implement the code, we will install the <strong><a href="https://polynonce.ru/pip-install-bitcoin/" target="_blank" rel="noreferrer noopener">Bitcoin</a></strong> package . This library allows you to create wallets, interact with the blockchain, create and sign transactions, and work with various address formats and private keys of the Bitcoin cryptocurrency.</p>
<pre class="wp-block-code has-text-color has-link-color wp-elements-9a0f1a67ae8617004ae12ce64ce4a4b7" style="color:#4092c2"><code><strong>!pip3 install bitcoin</strong></code></pre>
<hr class="wp-block-separator has-alpha-channel-opacity">
<blockquote class="wp-block-quote is-layout-flow wp-block-quote-is-layout-flow">
<p>Let’s run <a href="https://github.com/demining/CryptoDeepTools/blob/main/39BluetoothAttacks/priv_addr.py" target="_blank" rel="noreferrer noopener"><strong>the code</strong></a> to check the Bitcoin Address match:</p>
</blockquote>
<div class="wp-block-image">
<figure class="aligncenter"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-23-1024x865.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5584"></figure></div>
<pre class="wp-block-code has-text-color has-link-color wp-elements-6bf9d00fadc38373e174b80b977e71d7" style="color:#4092c2"><code><strong>__________________________________________________
Private Key WIF: 12d3428123e4262d6890e0ef149ce3c1335229b3f44ed6026bdec2921e796d34
Bitcoin Address: 1GSrCrtjZ6nk3Yn2wuY2qyXo8qPLGgAMqQ
total_received = 10.00000000 Bitcoin
__________________________________________________</strong></code></pre>
<p class="has-text-align-center has-text-color has-link-color wp-elements-117b680427be5af284252f0a05de9aa4" style="color:#2f8745;font-size:25px"><strong>That’s right! The private key corresponds to the Bitcoin Wallet.</strong></p>
<hr class="wp-block-separator has-alpha-channel-opacity">
<h2 class="wp-block-heading">Let’s open <strong><a href="https://cryptodeeptech.ru/bitaddress.html" target="_blank" rel="noreferrer noopener">bitaddress</a></strong> and check:</h2>
<pre class="wp-block-code has-text-color has-link-color wp-elements-287f39ebccb195a6d7c413dfcd418b61" style="color:#4092c2"><code><strong>ADDR: 1GSrCrtjZ6nk3Yn2wuY2qyXo8qPLGgAMqQ
WIF: 5HxaSsQFK9TDeNfTnNyXAzHXZe3hq3UzZ977GzdjSwEVVeEcDmZ
HEX: 12d3428123e4262d6890e0ef149ce3c1335229b3f44ed6026bdec2921e796d34</strong></code></pre>
<div class="wp-block-image">
<figure class="aligncenter"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-13.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5556"></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<h2 class="wp-block-heading">Results and steps to reduce the threat</h2>
<p>In today’s digital environment, securing devices and networks is critical. This paper analyzes a number of vulnerabilities found in various components, including ESP32 devices and software for working with cryptocurrencies such as Bitcoin. We examine flaws in private key verification code, transaction hashing methods, random key generation, ECC curve point verification, Y-coordinate recovery, and legacy hashing APIs. Particular attention is paid to the CVE-2025-27840 vulnerability in ESP32 microcontrollers, which allows attackers to inject fake updates and gain low-level access to the system. The potential implications of these vulnerabilities are discussed, including the ability to bypass code audit controls, gain access to private keys, and conduct supply chain attacks. The paper concludes with recommendations for strengthening security and preventing potential attacks.</p>
<h2 class="wp-block-heading">Relevance</h2>
<p>Billions of devices may now be vulnerable to hidden design flaws in a single component, identified as CVE-2025-27840. The vulnerabilities could allow attackers to spoof MAC addresses, gain unauthorized access to device memory, and conduct attacks via Bluetooth.</p>
<h2 class="wp-block-heading">Vulnerabilities and their analysis</h2>
<ul class="wp-block-list">
<li><strong>Private Key Derivation Vulnerability in<code>has_invalid_privkey</code></strong> : Lack of lower bound checking for Bitcoin private keys allows invalid keys (less than or equal to 0) to be used, which can lead to loss of funds.</li>
<li><strong>Bitcoin Transaction Signature Forgery Vulnerability in Function<code>electrum_sig_hash</code></strong> : Electrum’s use of a non-standard message hashing method makes it vulnerable to signature forgery attacks due to its incompatibility with BIP-137.</li>
<li><strong>Function Vulnerability <code>random_key</code>(Weak PRNG in Key Generation)</strong> : The use of the <code>random</code>key generation module in the Bitcoin network makes private keys predictable to attackers, since this module is not intended for cryptographic purposes.</li>
<li><strong>Vulnerability in Function <code>multiply</code>(Lack of ECC Curve Point Validation)</strong> : Insufficient validation of points in the ECC curve may allow an attacker to conduct invalid curve attacks, which may lead to forged signatures and network manipulation.</li>
<li><strong>Vulnerability in the function<code>ecdsa_raw_sign</code></strong> : Incorrect restoration of the Y-coordinate can lead to the substitution of a public key in the Bitcoin network.</li>
<li><strong>Function Vulnerability<code>bin_ripemd160</code></strong> : Legacy hashing APIs, especially those lacking RIPEMD-160, may be vulnerable to attacks, highlighting the importance of using up-to-date cryptographic libraries and regular security updates.</li>
</ul>
<hr class="wp-block-separator has-alpha-channel-opacity">
<div class="wp-block-image">
<figure class="aligncenter"><img decoding="async" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-22.png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi and Bluetooth" class="wp-image-5580"></figure></div>
<hr class="wp-block-separator has-alpha-channel-opacity">
<h2 class="wp-block-heading">Benefits of identifying and fixing vulnerabilities</h2>
<ol class="wp-block-list">
<li><strong>Preventing Financial Losses</strong> : Fixing vulnerabilities related to private keys and signature forgery helps prevent cryptocurrency users from losing funds.</li>
<li><strong>Protecting confidential data</strong> : Fixing vulnerabilities in ESP32 devices prevents unauthorized memory access and MAC address spoofing, which protects users’ confidential data.</li>
<li><strong>Improving Network Security</strong> : Fixing vulnerabilities in cryptographic functions such as <code>random_key</code>and <code>ecdsa_raw_sign</code>improves the overall security of the Bitcoin network and prevents potential attacks on transactions and signatures.</li>
<li><strong>Building User Trust</strong> : Timely identification and remediation of vulnerabilities helps build user trust in devices and software, which is especially important in the cryptocurrency and IoT space.</li>
<li><strong>Maintaining Security Standards</strong> : Keeping cryptographic libraries and APIs up to date and following modern security standards helps prevent the use of outdated and vulnerable components.</li>
</ol>
<h2 class="wp-block-heading">Conclusion</h2>
<p>The vulnerability identification and analysis presented in this paper highlight the need for continuous monitoring and improvement of device and software security. Addressing these vulnerabilities not only prevents potential attacks and financial losses, but also helps to build user confidence and comply with security standards. Implementing robust protection mechanisms and regular security updates are key to ensuring safe and reliable operation of digital systems. The need to improve security in devices and networks such as the ESP32 is becoming increasingly urgent.</p>
<hr class="wp-block-separator has-alpha-channel-opacity">
<h2 class="wp-block-heading">References:</h2>
<ol class="wp-block-list">
<li><em><a href="https://bitoncoin.org/12ib7dapvfvg82txkycwbnpn8kfyian1dr/" target="_blank" rel="noreferrer noopener">Recommendations for Eliminating Vulnerabilities in Bitcoin Code and ESP32 Devices</a></em></li>
<li><em><a href="https://bitoncoin.org/12tkqa9xsoowkzoerhmwnkstey55yebqkv/" target="_blank" rel="noreferrer noopener">Weaknesses in Bitcoin Implementation:</a> How Vulnerabilities in random_key and ecdsa_raw_sign Compromise Security</em></li>
<li><em><a href="https://bitoncoin.org/12tls9c9rsalt4ockxa1hb4itctsmxj2me" target="_blank" rel="noreferrer noopener">Analysis of the has_invalid_privkey Function Vulnerability:</a> Problems with Bitcoin Private Key Verification and Recommendations for Correction</em></li>
<li><em><a href="https://bitoncoin.org/14yk4mzjgo5nkknnmvjeueaqftlt795gec/" target="_blank" rel="noreferrer noopener">Public Key Substitution:</a> Vulnerability of the ecdsa_raw_sign Function, Risks Associated with Y-Coordinate Recovery, Code Examples to Demonstrate the Vulnerability</em></li>
<li><em><a href="https://bitoncoin.org/15z5yjaansxeynvr6uw6jqzlwq3n1hu6rx" target="_blank" rel="noreferrer noopener">Bitcoin Security:</a> Examining Risks Associated with Incorrect ECC Verification and Obsolete Hashing APIs</em></li>
<li><em><a href="https://bitoncoin.org/167zwtt8n6s4ya8cgjqnnqjdwdgy31vmhg" target="_blank" rel="noreferrer noopener">Security Risk Analysis:</a> Vulnerabilities in ESP32 Devices and the Bitcoin Network</em></li>
<li><em><a href="https://bitoncoin.org/18zultkqnljp987ldxuyvjekynnavxif2b" target="_blank" rel="noreferrer noopener">Obsolete Hashing APIs in Bitcoin:</a> Vulnerabilities of the bin_ripemd160 Function</em></li>
<li><em><a href="https://bitoncoin.org/198amn6zyaczwre5nvntumyj5qkfy4g3hi" target="_blank" rel="noreferrer noopener">Fake Updates and Access to Private Keys:</a> ESP32 Vulnerabilities and Their Consequences</em></li>
<li><em><a href="https://bitoncoin.org/1aylzyn7sgu5fqlbtadbzqkm4b6udt6bw6" target="_blank" rel="noreferrer noopener">Bitcoin Security Risks:</a> Vulnerabilities in Key Verification and Transaction Generation Functions</em></li>
<li><em><a href="https://bitoncoin.org/1bafwqhh9pnkz3mzdq1twrtkkshvckc3fv" target="_blank" rel="noreferrer noopener">Problems with Key Generation:</a> random_key Function Vulnerability, Weak Pseudo-Random Number Generator and its Consequences</em></li>
<li><em><a href="https://bitoncoin.org/1beoudc6jthpitvpz3gr3lqnbgb7dkrrtc" target="_blank" rel="noreferrer noopener">Shortcomings of Cryptographic Functions in Bitcoin and Potential Threats to the Network</a></em></li>
<li><em><a href="https://bitoncoin.org/1cpazitqeeixposftjxu74udgbpeaotzom" target="_blank" rel="noreferrer noopener">Attacks on Elliptic Curve:</a> multiply Function Vulnerability, Insufficient Verification of Points on the ECC Curve, Possible Attack Vectors</em></li>
<li><em><a href="https://bitoncoin.org/1dzje3anaklasy2n6e5toj4cqcxrvdvwsf" target="_blank" rel="noreferrer noopener">The Importance of Current Cryptographic Libraries and Regular Updates Conclusion:</a> The Need to Improve Security in Networks and Devices</em></li>
<li><em><a href="https://bitoncoin.org/1f1miyfqwtzdlicbxthhnniw7wawpuccr" target="_blank" rel="noreferrer noopener">Potential Attacks Using Invalid Curves Public Key Substitution:</a> Vulnerability of the ecdsa_raw_sign Function</em></li>
<li><em><a href="https://bitoncoin.org/1f34duy2eemz5msrvfepvzy7y1rbsnaywc" target="_blank" rel="noreferrer noopener">Recommendations for Eliminating Vulnerabilities and Improving Protection Each title reflects key aspects of the article and can be used to structure the research</a></em></li>
<li><em><a href="https://bitoncoin.org/1feexv6bahb8ybzjqqmjjrccrhgw9sb6uf" target="_blank" rel="noreferrer noopener">Weak PRNG in Bitcoin Key Generation:</a> Consequences of Using a Non-Deterministic random_key</em></li>
<li><em><a href="https://bitoncoin.org/1fjuzzqfvmbimgw6jtcxefdd64amy7mscf" target="_blank" rel="noreferrer noopener">Analysis of Vulnerability CVE-2025-27840:</a> How Architectural Flaws Can Threaten Billions of Devices Vulnerability of the has_invalid_privkey Function</em></li>
<li><em><a href="https://bitoncoin.org/1hlvats3zr3oev9ya7pzp3gb9gqfg6xyjt" target="_blank" rel="noreferrer noopener">Impact of Vulnerabilities in ESP32 Microcontrollers on the Security of IoT Devices</a></em></li>
<li><em><a href="https://bitoncoin.org/1jxmkknk1b3p7r8ddptnnmgelzdcgpadjb" target="_blank" rel="noreferrer noopener">Methods for Exploiting Vulnerabilities in ESP32 Microcontrollers:</a> Attacks via Bluetooth and Wi-Fi</em></li>
<li><em><a href="https://bitoncoin.org/1kbrskrt3geerutuuyyusq35jwkbrawjym" target="_blank" rel="noreferrer noopener">Hidden Vulnerabilities in ESP32 and Their Impact on the Security of IoT Devices</a></em></li>
<li><em><a href="https://bitoncoin.org/1lbbmkr9muf7rjjbbzqqvznqprravenavs" target="_blank" rel="noreferrer noopener">Security Issues in ESP32 Devices:</a> Disclosure of Vulnerability CVE-2025-27840</em></li>
<li><em><a href="https://bitoncoin.org/1ldrcdxfbsnmcyyndeypunztiyzvfbeqec" target="_blank" rel="noreferrer noopener">ESP32 Architectural Vulnerabilities:</a> Revealing Hidden Commands and Their Impact on IoT Security</em></li>
<li><em><a href="https://bitoncoin.org/1p1ithxbh542gmk1kznxyji4e4iwpvsbrt" target="_blank" rel="noreferrer noopener">Vulnerabilities in Bitcoin Code:</a> Technical Analysis and Exploitation Methods</em></li>
<li><em><a href="https://bitoncoin.org/1peizmg76cf96nuqryg8xuozwlqozu5zgw" target="_blank" rel="noreferrer noopener">Analysis of Vulnerabilities in Bitcoin:</a> From Cryptographic Shortcomings to Obsolete APIs</em></li>
<li><em><a href="https://bitoncoin.org/1ucxxzqsef4zny2hrwaqktvpklptukrtt" target="_blank" rel="noreferrer noopener">CVE-2025-27840 Vulnerabilities in ESP32 Microcontrollers:</a> Exposing Billions of IoT Devices to Risk</em></li>
<li><em><a href="https://bitoncoin.org/dockeyhunt-%EA%B0%9C%EC%9D%B8-%ED%82%A4-%EA%B3%84%EC%82%B0%EA%B8%B0" target="_blank" rel="noreferrer noopener">Non-Standard Hashing Methods and Their Vulnerabilities Problems with Key Generation:</a> random_key Vulnerability</em></li>
<li><em><a href="https://cryptodeeptech.ru/lattice-attack-249bits" target="_blank" rel="noreferrer noopener">Lack of ECC Point Verification as a Potential Vulnerability in the Bitcoin multiply Function</a></em></li>
<li><em><a href="https://cryptodeeptech.ru/signature-malleability" target="_blank" rel="noreferrer noopener">Risks of Recovering the Y-Coordinate in Elliptic-Curve Cryptography Obsolete Hashing APIs:</a> bin_ripemd160 Function Vulnerability</em></li>
<li><em><a href="https://cryptodeeptech.ru/blockchain-attack-vectors" target="_blank" rel="noreferrer noopener">Vulnerability in the ecdsa_raw_sign Function:</a> Risk of Public Key Substitution During Y-Coordinate Recovery</em></li>
<li><em><a href="https://cryptodeeptech.ru/twist-attack" target="_blank" rel="noreferrer noopener">Hidden Vulnerabilities:</a> A Threat to Modern Technologies CVE-2025-27840: Overview of Vulnerabilities in the ESP32 Architecture</em></li>
<li><em><a href="https://cryptodeeptech.ru/rowhammer-attack" target="_blank" rel="noreferrer noopener">Overview of Current Security Threats Hidden List of Vulnerabilities:</a> Potential Risks for ESP32 Implementation of Fake Updates and Low-Level Access</em></li>
<li><em><a href="https://cryptodeeptech.ru/whitebox-attack" target="_blank" rel="noreferrer noopener">Problems with Private Key Verification and Their Consequences Forgery of Transaction Signatures:</a> electrum_sig_hash Vulnerability</em></li>
<li><em><a href="https://club.dns-shop.ru/digest/139788-v-mikrokontrollere-espressif-esp32-obnarujen-skryityii-bekdor-po" target="_blank" rel="noreferrer noopener">Vulnerability of Bitcoin Transaction Signature Forgery Due to Non-Standard Hashing in Electrum</a></em></li>
<li><em><a href="https://github.com/svtrostov/oclexplorer/issues/6" target="_blank" rel="noreferrer noopener">Risks of Using Unreliable PRNGs in Bitcoin Insufficient ECC Point Verification:</a> multiply Function Vulnerability</em></li>
<li><em><a href="https://hightech.plus/2025/03/10/millioni-umnih-ustroistv-pod-ugrozoi-iz-za-uyazvimosti-v-bluetooth-chipe" target="_blank" rel="noreferrer noopener">Overview of Vulnerabilities in Bitcoin:</a> Potential Risks for Private Keys and Transactions</em></li>
<li><em><a href="https://proglib.io/p/new-bitcoin" target="_blank" rel="noreferrer noopener">Critical Security Analysis of ESP32 and Bitcoin:</a> Vulnerabilities and Methods of Protection</em></li>
<li><em><a href="https://securitymedia.org/news/v-chipakh-esp32-nashli-skrytye-komandy-kotorye-otkryvayut-dostup-k-ustroystvam.html" target="_blank" rel="noreferrer noopener">Obsolete Hashing APIs:</a> bin_ripemd160 Function Vulnerability Problems with RIPEMD-160 Implementation Importance of Current Cryptographic Libraries</em></li>
<li><em><a href="https://www.bleepingcomputer.com/news/security/undocumented-commands-found-in-bluetooth-chip-used-by-a-billion-devices" target="_blank" rel="noreferrer noopener">Vulnerability of the electrum_sig_hash Function:</a> Bitcoin Transaction Signature Forgery Non-Standard Hashing Method and its Consequences Examples of Attacks Based on Incompatibility with BIP-137</em></li>
<li><em><a href="https://www.cnews.ru/news/top/2025-03-11_nezadokumentirovannye_komandy" target="_blank" rel="noreferrer noopener">Analysis of Vulnerabilities in Bitcoin Implementation:</a> From Key Generation to Signature Forgery</em></li>
<li><em><a href="https://www.forbes.com/sites/daveywinder/2025/03/10/identity-theft-warning-hidden-commands-in-1-billion-bluetooth-chips" target="_blank" rel="noreferrer noopener">CVE-2025-27840:</a> Vulnerability in ESP32, Allowing Unauthorized Firmware Updates and Access to Private Keys</em></li>
<li><em><a href="https://www.securitylab.ru/news/557149.php" target="_blank" rel="noreferrer noopener">Vulnerability in Bitcoin Private Key Verification:</a> Bypassing Lower Bound Control</em></li>
</ol>
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<figure class="aligncenter size-full"><a href="https://dzen.ru/video/watch/6784be61b09e46422395c236" target="_blank" rel=" noreferrer noopener"><img loading="lazy" decoding="async" width="511" height="441" src="./Bitcoin Cryptanalysis CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi Bluetooth - CRYPTO DEEP TECH_files/image-13(1).png" alt="Bitcoin Cryptanalysis: CVE-2025-27840 Vulnerability in ESP32 Microcontrollers Puts Billions of IoT Devices at Risk via Wi-Fi & Bluetooth" class="wp-image-3295" srcset="https://cryptodeeptech.ru/wp-content/uploads/2025/03/image-13.png 511w, https://cryptodeeptech.ru/wp-content/uploads/2025/03/image-13-300x259.png 300w" sizes="auto, (max-width: 511px) 100vw, 511px"></a></figure></div>
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<p>This material was created for the <a href="https://cryptodeeptech.ru/" target="_blank" rel="noreferrer noopener">CRYPTO DEEP TECH</a> portal to ensure financial data security and cryptography on elliptic curves <a href="https://www.youtube.com/@cryptodeeptech" target="_blank" rel="noreferrer noopener">secp256k1</a> against weak <a href="https://github.com/demining/CryptoDeepTools" target="_blank" rel="noreferrer noopener">ECDSA</a> signatures in the <a href="https://t.me/cryptodeeptech" target="_blank" rel="noreferrer noopener">BITCOIN</a> cryptocurrency . The creators of the software are not responsible for the use of materials.</p>
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<p><strong><a href="https://github.com/demining/CryptoDeepTools/tree/main/39BluetoothAttacks" target="_blank" rel="noreferrer noopener">Source code</a></strong></p>
<p><strong><a href="https://colab.research.google.com/drive/15lPDHeTo7FkrPY7v4qS7X6hO4x27qT2Y" target="_blank" rel="noreferrer noopener">Google Colab</a></strong></p>
<p><strong><a href="https://bitcoinchatgpt.org/" target="_blank" rel="noreferrer noopener">BitcoinChatGPT</a></strong></p>
<p><strong><a href="https://dustattack.org/small-subgroup-attack" target="_blank" rel="noreferrer noopener">Small Subgroup Attack</a></strong></p>
<p><strong><a href="https://dockeyhunt.com/dockeyhunt-deep-learning" target="_blank" rel="noreferrer noopener">Dockeyhunt Deep Learning</a></strong></p>
<p><strong><a href="https://t.me/cryptodeeptech" target="_blank" rel="noreferrer noopener">Telegram: https://t.me/cryptodeeptech</a></strong></p>
<p><strong><a href="https://youtu.be/nBeZWm2z5o4" target="_blank" rel="noreferrer noopener">Video material: https://youtu.be/nBeZWm2z5o4</a></strong></p>
<p><strong><a href="https://dzen.ru/video/watch/6784be61b09e46422395c236" target="_blank" rel="noreferrer noopener">Video tutorial: https://dzen.ru/video/watch/6784be61b09e46422395c236</a></strong></p>
<p><strong><a href="https://cryptodeeptech.ru/bitcoin-bluetooth-attacks" target="_blank" rel="noreferrer noopener">Source: https://cryptodeeptech.ru/bitcoin-bluetooth-attacks</a></strong></p>
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