CVE-2020-23909
📋 TL;DR
CVE-2020-23909 is a heap-based buffer over-read vulnerability in the png_convert_4 function of AdvanceMAME's pngex.cc file. This vulnerability allows attackers to read sensitive memory contents, potentially leading to information disclosure or application crashes. Users of AdvanceMAME versions through 2.1 are affected.
💻 Affected Systems
- AdvanceMAME
📦 What is this software?
Advancemame by Advancemame
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution through memory corruption leading to complete system compromise, though this is less likely with buffer over-read vulnerabilities.
Likely Case
Application crash (denial of service) or information disclosure of sensitive memory contents.
If Mitigated
Limited impact with proper memory protections (ASLR, DEP) and sandboxing in place.
🎯 Exploit Status
Exploitation requires crafting malicious PNG files. The bug report includes proof-of-concept details showing crash conditions.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: AdvanceMAME 2.2 and later
Vendor Advisory: https://sourceforge.net/p/advancemame/bugs/285/
Restart Required: Yes
Instructions:
1. Download latest version from https://www.advancemame.it/download 2. Uninstall old version 3. Install new version 4. Restart any running AdvanceMAME processes
🔧 Temporary Workarounds
Disable PNG support
allRemove or disable PNG image processing functionality
Not applicable - configuration change only
Sandbox execution
linuxRun AdvanceMAME in restricted environment with limited permissions
firejail --net=none advancemame
bwrap --unshare-all --ro-bind / / advancemame
🧯 If You Can't Patch
- Implement strict file validation for PNG inputs
- Deploy memory protection mechanisms (ASLR, DEP) and monitor for crashes
🔍 How to Verify
Check if Vulnerable:
Check AdvanceMAME version: advancemame --version | grep -i versionCheck Version:
advancemame --versionVerify Fix Applied:
Verify version is 2.2 or higher and test with known malicious PNG files📡 Detection & Monitoring
Log Indicators:
- Application crashes with segmentation faults
- Memory access violation errors
- Unexpected termination of advancemame processes
Network Indicators:
- Unusual PNG file transfers to systems running AdvanceMAME
SIEM Query:
process_name:"advancemame" AND (event_type:"crash" OR exit_code:139 OR exit_code:-1073741819)