CVE-2021-29366
📋 TL;DR
A buffer overflow vulnerability in IrfanView 4.57 allows attackers to execute arbitrary code by tricking users into opening a specially crafted RLE image file. This affects all users running the vulnerable version of IrfanView, potentially leading to complete system compromise.
💻 Affected Systems
- IrfanView
📦 What is this software?
Irfanview by Irfanview
⚠️ Risk & Real-World Impact
Worst Case
Complete system takeover with administrative privileges, data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Local privilege escalation leading to user account compromise, data exfiltration, or malware installation.
If Mitigated
Limited impact due to sandboxing, application whitelisting, or restricted user privileges preventing full system compromise.
🎯 Exploit Status
Exploitation requires user interaction to open a malicious file. The GitHub research repository contains proof-of-concept code demonstrating the vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: IrfanView 4.58 or later
Vendor Advisory: https://www.irfanview.com/main_history.htm
Restart Required: No
Instructions:
1. Download latest IrfanView from official website. 2. Run installer. 3. Follow installation prompts. 4. Verify version is 4.58 or higher.
🔧 Temporary Workarounds
Disable RLE file association
windowsRemove IrfanView as default handler for .rle files to prevent automatic exploitation
Control Panel > Default Programs > Set Associations > Find .rle > Change to another program
Block RLE files at perimeter
allPrevent .rle files from entering the network via email or web gateways
🧯 If You Can't Patch
- Restrict user privileges to prevent system-wide compromise if exploited
- Implement application whitelisting to block unauthorized code execution
🔍 How to Verify
Check if Vulnerable:
Check IrfanView version via Help > About. If version is 4.57, system is vulnerable.Check Version:
irfanview.exe /?Verify Fix Applied:
Verify version is 4.58 or higher in Help > About dialog.📡 Detection & Monitoring
Log Indicators:
- Process creation from IrfanView with unusual parent processes
- Crash logs from IrfanView with memory access violations
Network Indicators:
- Downloads of .rle files from untrusted sources
- Unusual outbound connections after IrfanView execution
SIEM Query:
ProcessName="i_view32.exe" OR ProcessName="i_view64.exe" AND (CommandLine CONTAINS ".rle" OR ParentImage CONTAINS suspicious_process)