CVE-2021-21082
📋 TL;DR
This memory corruption vulnerability in Adobe Photoshop allows attackers to execute arbitrary code by tricking users into opening malicious files. It affects Photoshop versions 21.2.5 and earlier, and 22.2 and earlier. Successful exploitation requires user interaction but gives attackers full control of the victim's system.
💻 Affected Systems
- Adobe Photoshop
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining full control of the victim's computer, potentially leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Local privilege escalation leading to data exfiltration, installation of backdoors, or credential harvesting from the compromised user account.
If Mitigated
Limited impact if user opens file in sandboxed environment or with restricted privileges, though still potential for local data access.
🎯 Exploit Status
Exploitation requires user to open malicious file but no authentication needed. Attack complexity is low once malicious file is opened.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 21.2.6 and 22.3
Vendor Advisory: https://helpx.adobe.com/security/products/photoshop/apsb21-17.html
Restart Required: Yes
Instructions:
1. Open Adobe Creative Cloud application. 2. Navigate to 'Apps' section. 3. Find Photoshop and click 'Update'. 4. Restart Photoshop after update completes.
🔧 Temporary Workarounds
Restrict Photoshop file execution
windowsConfigure application control policies to restrict Photoshop from opening files from untrusted sources
User education and file validation
allTrain users to only open Photoshop files from trusted sources and validate file integrity
🧯 If You Can't Patch
- Implement application whitelisting to restrict Photoshop execution to trusted directories only
- Configure user accounts with minimal privileges and run Photoshop in sandboxed environments
🔍 How to Verify
Check if Vulnerable:
Check Photoshop version via Help > About Photoshop in the application menuCheck Version:
On Windows: Check registry at HKEY_LOCAL_MACHINE\SOFTWARE\Adobe\Photoshop\[Version]\PluginVersion. On macOS: Check /Applications/Adobe Photoshop [Version]/Adobe Photoshop [Version].app/Contents/Info.plistVerify Fix Applied:
Verify version is 21.2.6 or higher for Photoshop 21.x, or 22.3 or higher for Photoshop 22.x📡 Detection & Monitoring
Log Indicators:
- Photoshop crash logs with memory access violations
- Unexpected Photoshop process spawning child processes
- Photoshop accessing unusual file locations
Network Indicators:
- Photoshop process making unexpected outbound connections after file open
- DNS requests to suspicious domains following Photoshop execution
SIEM Query:
EventID=1 AND (Image='*photoshop.exe' OR Image='*Adobe Photoshop*') AND (CommandLine='*malicious*' OR ParentCommandLine='*malicious*')