CVE-2021-21056
📋 TL;DR
CVE-2021-21056 is an out-of-bounds read vulnerability in Adobe Framemaker that allows arbitrary code execution when a user opens a malicious file. Attackers can exploit this to run code with the victim's privileges, affecting all users of vulnerable Framemaker versions.
💻 Affected Systems
- Adobe Framemaker
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise via arbitrary code execution leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Malware installation or data exfiltration when users open malicious documents from untrusted sources.
If Mitigated
Limited impact with proper patching and user awareness preventing malicious file execution.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file) but the vulnerability itself is straightforward to exploit.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2020.0.2 or later
Vendor Advisory: https://helpx.adobe.com/security/products/framemaker/apsb21-14.html
Restart Required: Yes
Instructions:
1. Open Adobe Framemaker. 2. Go to Help > Check for Updates. 3. Install available updates. 4. Restart the application.
🔧 Temporary Workarounds
Disable automatic file opening
allConfigure Framemaker to not automatically open files and require explicit user confirmation.
Restrict file types
allUse application whitelisting to block execution of suspicious Framemaker files.
🧯 If You Can't Patch
- Implement strict user training about opening files from untrusted sources
- Deploy endpoint protection with behavior monitoring for suspicious Framemaker processes
🔍 How to Verify
Check if Vulnerable:
Check Framemaker version in Help > About Framemaker. If version is 2020.0.1 or earlier, system is vulnerable.Check Version:
Not applicable - check via application GUIVerify Fix Applied:
Verify version is 2020.0.2 or later in Help > About Framemaker.📡 Detection & Monitoring
Log Indicators:
- Multiple crash reports from Framemaker.exe
- Unusual file access patterns from Framemaker
Network Indicators:
- Outbound connections from Framemaker to unknown IPs after file opening
SIEM Query:
process_name:"framemaker.exe" AND (event_type:crash OR file_path:*.fm)