CVE-2021-44709
📋 TL;DR
CVE-2021-44709 is a heap overflow vulnerability in Adobe Acrobat Reader DC that allows arbitrary code execution when a user opens a malicious PDF file. The vulnerability affects multiple versions across different release tracks. Attackers can exploit this to run code with the same privileges as the current user.
💻 Affected Systems
- Adobe Acrobat Reader DC
📦 What is this software?
Acrobat by Adobe
Acrobat by Adobe
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through arbitrary code execution, leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Malware installation or credential theft when users open malicious PDFs from phishing emails or compromised websites.
If Mitigated
Limited impact with proper application sandboxing, least privilege user accounts, and security software that blocks malicious PDFs.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file). Heap overflow vulnerabilities in PDF readers are commonly exploited in targeted attacks.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 21.007.20099 (Continuous Track), 20.004.30017 (Classic 2020 Track), 17.011.30204 (Classic 2017 Track) and later versions
Vendor Advisory: https://helpx.adobe.com/security/products/acrobat/apsb22-01.html
Restart Required: Yes
Instructions:
1. Open Adobe Acrobat Reader DC. 2. Go to Help > Check for Updates. 3. Follow prompts to install available updates. 4. Restart the application when prompted.
🔧 Temporary Workarounds
Disable JavaScript in Adobe Reader
allPrevents exploitation vectors that use JavaScript to trigger the vulnerability
Edit > Preferences > JavaScript > Uncheck 'Enable Acrobat JavaScript'
Use Protected View
allOpen PDFs in Protected View mode to limit potential damage
File > Properties > Security > Enable Protected View for all files
🧯 If You Can't Patch
- Restrict PDF file opening to trusted sources only using application control policies
- Implement network segmentation to limit lateral movement if exploitation occurs
🔍 How to Verify
Check if Vulnerable:
Check Adobe Reader version in Help > About Adobe Acrobat Reader DCCheck Version:
On Windows: "C:\Program Files\Adobe\Acrobat Reader DC\Reader\AcroRd32.exe" /?Verify Fix Applied:
Verify version is 21.007.20099 or higher (Continuous), 20.004.30017 or higher (Classic 2020), or 17.011.30204 or higher (Classic 2017)📡 Detection & Monitoring
Log Indicators:
- Adobe Reader crash logs with heap corruption errors
- Windows Event Logs showing unexpected process termination
Network Indicators:
- Unusual outbound connections from Adobe Reader process
- PDF downloads from suspicious sources
SIEM Query:
process_name:"AcroRd32.exe" AND (event_id:1000 OR event_id:1001) AND exception_code:0xc0000005