CVE-2021-21782
📋 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 SGI format processing. Organizations using ImageGear 19.8 for image processing are affected, particularly those handling untrusted SGI image 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 allowing partial control.
If Mitigated
Contained application crash with no privilege escalation if proper sandboxing exists.
🎯 Exploit Status
Exploitation requires delivering a malicious SGI file; public technical details exist in Talos reports.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: ImageGear 19.9 or later (check Accusoft advisory)
Vendor Advisory: https://www.accusoft.com/resources/security-advisories/
Restart Required: Yes
Instructions:
1. Contact Accusoft for updated ImageGear version. 2. Backup configurations. 3. Install update. 4. Restart affected services. 5. Validate functionality.
🔧 Temporary Workarounds
Block SGI file processing
allConfigure applications to reject SGI format files at input validation layer.
Application-specific configuration - implement file type validation to block .sgi, .rgb, .bw extensions
Sandbox image processing
allIsolate ImageGear in container or restricted environment to limit exploit impact.
docker run --read-only --cap-drop=ALL [image]
Windows: Use AppContainer or Job Objects
🧯 If You Can't Patch
- Implement strict input validation to block all SGI format files from untrusted sources.
- Deploy application allowlisting to prevent unauthorized code execution from ImageGear processes.
🔍 How to Verify
Check if Vulnerable:
Check ImageGear version; if 19.8 and processing SGI files, assume vulnerable.Check Version:
Windows: Check program version in Control Panel; Linux: Check library version or consult application documentation.Verify Fix Applied:
Verify ImageGear version is 19.9+ and test with known malicious SGI file (in safe environment).📡 Detection & Monitoring
Log Indicators:
- Application crashes from ImageGear processes
- Unexpected memory access errors in logs
Network Indicators:
- Inbound SGI file transfers to vulnerable systems
SIEM Query:
source="*ImageGear*" AND (event="crash" OR event="exception")