CVE-2021-29364
📋 TL;DR
This buffer overflow vulnerability in IrfanView allows attackers to execute arbitrary code by tricking users into opening a specially crafted RLE image file. Users of IrfanView 4.57 on Windows systems are affected when they open malicious files.
💻 Affected Systems
- IrfanView
📦 What is this software?
Irfanview by Irfanview
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining full control of the victim's computer, enabling data theft, ransomware deployment, or lateral movement within networks.
Likely Case
Local privilege escalation or remote code execution when user opens malicious file, potentially leading to malware installation or data exfiltration.
If Mitigated
Limited impact if application runs with minimal privileges, sandboxed, or network segmentation prevents lateral movement.
🎯 Exploit Status
Exploitation requires user to open malicious file; buffer overflow in Formats!ReadRAS_W+0x1001 function.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.58 and later
Vendor Advisory: https://www.irfanview.com/main_history.htm
Restart Required: No
Instructions:
1. Download IrfanView 4.58 or later from official website. 2. Run installer. 3. Follow installation prompts. 4. Verify version in Help > About.
🔧 Temporary Workarounds
Disable RLE file association
windowsRemove IrfanView as default handler for .rle files to prevent automatic opening
Control Panel > Default Programs > Set Associations > Find .rle > Change program
User awareness training
allEducate users not to open RLE files from untrusted sources
🧯 If You Can't Patch
- Run IrfanView with restricted user privileges (not as administrator)
- Implement application whitelisting to prevent execution of unauthorized code
🔍 How to Verify
Check if Vulnerable:
Check IrfanView version in Help > About; if version is 4.57, system is vulnerable.Check Version:
irfanview.exe /?Verify Fix Applied:
Verify version is 4.58 or later in Help > About menu.📡 Detection & Monitoring
Log Indicators:
- Process creation events from IrfanView with unusual command-line arguments
- Crash reports from IrfanView with memory access violations
Network Indicators:
- Unusual outbound connections following IrfanView execution
- File downloads of .rle extensions
SIEM Query:
ProcessName="irfanview.exe" AND (CommandLine CONTAINS ".rle" OR ParentProcess CONTAINS unusual_pattern)