CVE-2021-21065
📋 TL;DR
CVE-2021-21065 is an out-of-bounds write vulnerability in Adobe Bridge that allows arbitrary code execution when a user opens a malicious TTF file. It affects users of Adobe Bridge version 11.0 and earlier, requiring user interaction to exploit.
💻 Affected Systems
- Adobe Bridge
📦 What is this software?
Bridge by Adobe
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining control as the current user, leading to data theft, ransomware deployment, or lateral movement.
Likely Case
Local code execution resulting in malware installation, file corruption, or system disruption for the affected user.
If Mitigated
Limited impact with no code execution if patched or workarounds applied, though file parsing errors may occur.
🎯 Exploit Status
Exploitation requires user interaction (opening a file), and no public proof-of-concept has been disclosed as of analysis.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Adobe Bridge 11.0.1 or later
Vendor Advisory: https://helpx.adobe.com/security/products/bridge/apsb21-07.html
Restart Required: Yes
Instructions:
1. Open Adobe Bridge. 2. Go to Help > Check for Updates. 3. Follow prompts to install version 11.0.1 or later. 4. Restart the application.
🔧 Temporary Workarounds
Disable TTF file parsing
windowsPrevent Adobe Bridge from processing TTF files to block exploitation vectors.
Not applicable; configure via application settings or group policy.
User awareness training
allEducate users to avoid opening untrusted TTF files from unknown sources.
🧯 If You Can't Patch
- Restrict user permissions to limit damage from code execution.
- Use application whitelisting to block unauthorized software execution.
🔍 How to Verify
Check if Vulnerable:
Check Adobe Bridge version via Help > About Adobe Bridge; if version is 11.0 or earlier, it is vulnerable.Check Version:
On Windows: wmic product where name="Adobe Bridge" get versionVerify Fix Applied:
Verify version is 11.0.1 or later after patching and test with safe TTF files.📡 Detection & Monitoring
Log Indicators:
- Unusual process creation from Adobe Bridge, crashes when opening TTF files.
Network Indicators:
- No direct network indicators; focus on file activity.
SIEM Query:
EventID=4688 AND ProcessName="Bridge.exe" AND CommandLine LIKE "%.ttf%"