CVE-2021-21006
📋 TL;DR
Adobe Photoshop versions 22.1 and earlier contain a heap buffer overflow vulnerability when processing malicious font files. Successful exploitation allows attackers to execute arbitrary code on the victim's system. This affects all users running vulnerable Photoshop versions who open untrusted files.
💻 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 malware installation, data exfiltration, or persistence mechanisms being established on the affected workstation.
If Mitigated
No impact if users only open trusted files from verified sources and the application is properly patched.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file) and knowledge of heap manipulation techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 22.1.1 and later
Vendor Advisory: https://helpx.adobe.com/security/products/photoshop/apsb21-01.html
Restart Required: Yes
Instructions:
1. Open Adobe Creative Cloud application 2. Navigate to 'Apps' tab 3. Find Photoshop and click 'Update' 4. Restart Photoshop after update completes
🔧 Temporary Workarounds
Restrict font file processing
allConfigure Photoshop to block or warn about suspicious font files through security settings
🧯 If You Can't Patch
- Implement application whitelisting to prevent execution of malicious payloads
- Educate users to never open Photoshop files from untrusted sources
🔍 How to Verify
Check if Vulnerable:
Check Photoshop version via Help > About Photoshop. If version is 22.1 or earlier, system is vulnerable.Check Version:
Photoshop: Help > About PhotoshopVerify Fix Applied:
Verify Photoshop version is 22.1.1 or later via Help > About Photoshop.📡 Detection & Monitoring
Log Indicators:
- Photoshop crash logs with memory access violations
- Unexpected font file processing in application logs
Network Indicators:
- Unusual outbound connections after opening Photoshop files
- DNS requests to suspicious domains post-file opening
SIEM Query:
EventID=1000 OR EventID=1001 AND ProcessName="Photoshop.exe" AND ExceptionCode="c0000005"