CVE-2021-21784
📋 TL;DR
This vulnerability allows attackers to execute arbitrary code or cause denial of service by exploiting an out-of-bounds write in Accusoft ImageGear's JPG processing. It affects systems using ImageGear 19.8 to parse untrusted JPG files. The vulnerability can be triggered remotely if the software processes malicious files.
💻 Affected Systems
- Accusoft ImageGear
📦 What is this software?
Imagegear by Accusoft
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Application crash (denial of service) or limited memory corruption affecting stability.
If Mitigated
Contained application crash with no privilege escalation if proper sandboxing exists.
🎯 Exploit Status
Exploitation requires delivering a malicious JPG file to the vulnerable application. The Talos report includes technical details that could facilitate weaponization.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 19.9 or later
Vendor Advisory: https://www.accusoft.com/products/imagegear/
Restart Required: Yes
Instructions:
1. Download ImageGear 19.9 or later from Accusoft.
2. Uninstall the vulnerable version (19.8).
3. Install the patched version.
4. Restart any applications using ImageGear.
🔧 Temporary Workarounds
Disable JPG processing
allConfigure applications to reject JPG files or use alternative image libraries.
Input validation
allImplement strict file validation before passing JPGs to ImageGear.
🧯 If You Can't Patch
- Isolate systems using ImageGear from untrusted networks.
- Implement application allowlisting to prevent unauthorized execution.
🔍 How to Verify
Check if Vulnerable:
Check if ImageGear 19.8 is installed via system inventory tools or by examining application dependencies.Check Version:
Depends on integration; consult Accusoft documentation for specific version query methods.Verify Fix Applied:
Verify ImageGear version is 19.9 or later using vendor documentation or version check utilities.📡 Detection & Monitoring
Log Indicators:
- Application crashes related to ImageGear or JPG processing
- Unexpected memory access errors in application logs
Network Indicators:
- Unusual JPG file transfers to systems using ImageGear
SIEM Query:
ImageGear AND (crash OR memory) OR JPG AND suspicious_file