CVE-2021-27362
📋 TL;DR
This vulnerability is a critical memory corruption flaw in the WPG plugin for IrfanView image viewer. Attackers can exploit it by tricking users into opening a malicious WPG file, potentially leading to remote code execution. Users of IrfanView with the vulnerable WPG plugin are affected.
💻 Affected Systems
- IrfanView WPG Plugin
📦 What is this software?
Wpg by Irfanview
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining full control of the victim's computer, data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Remote code execution leading to malware installation, credential theft, or system disruption when users open malicious WPG files.
If Mitigated
Limited impact with proper application sandboxing, restricted user privileges, and network segmentation preventing lateral movement.
🎯 Exploit Status
Exploitation requires user interaction to open a malicious WPG file. The vulnerability is a read access violation that can lead to control flow hijacking.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: WPG plugin version 3.1.0.0 or later
Vendor Advisory: https://www.irfanview.com/plugins.htm
Restart Required: No
Instructions:
1. Download latest WPG plugin from IrfanView website. 2. Close IrfanView. 3. Replace existing WPG plugin files with new version. 4. Restart IrfanView.
🔧 Temporary Workarounds
Disable WPG plugin
windowsRemove or disable the vulnerable WPG plugin from IrfanView
Remove WPG.dll from IrfanView\Plugins\ folder
Block WPG files at perimeter
allConfigure email/web gateways to block .wpg files
🧯 If You Can't Patch
- Restrict user privileges to prevent system-wide impact if exploited
- Implement application whitelisting to block unauthorized executables
🔍 How to Verify
Check if Vulnerable:
Check WPG.dll version in IrfanView\Plugins\ folder. Right-click file > Properties > Details tab.Check Version:
wmic datafile where name="C:\\Program Files\\IrfanView\\Plugins\\WPG.dll" get versionVerify Fix Applied:
Verify WPG.dll version is 3.1.0.0 or higher📡 Detection & Monitoring
Log Indicators:
- IrfanView crash logs with WPG-related errors
- Windows Application Event Logs showing IrfanView crashes
Network Indicators:
- Inbound WPG file transfers via email/web
- Outbound connections from IrfanView process after file opening
SIEM Query:
source="windows" AND (process="iview*.exe" AND event_id=1000) OR (file_extension=".wpg" AND action="download")