CVE-2021-44711
📋 TL;DR
This CVE describes an integer overflow vulnerability in Adobe Acrobat Reader DC that could allow arbitrary code execution when a user opens a malicious PDF file. The vulnerability affects multiple versions across different release tracks and could lead to complete system compromise in the context of 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 with attacker gaining the same privileges as the logged-in user, potentially leading to data theft, ransomware deployment, or lateral movement.
Likely Case
Malicious PDF files delivered via phishing or compromised websites lead to malware installation or credential theft on individual workstations.
If Mitigated
With proper security controls, the impact is limited to isolated workstation compromise that can be contained through network segmentation and endpoint protection.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file). No public exploit code was available at disclosure time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 21.007.20099 (21.x track), 20.004.30017 (20.x track), 17.011.30204 (17.x track) or later
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 JavaScript execution which may be used in exploitation chains
Edit > Preferences > JavaScript > Uncheck 'Enable Acrobat JavaScript'
Use Protected View
allOpen PDFs in Protected View mode to limit potential damage
File > Open > Select 'Protected View' option when opening untrusted files
🧯 If You Can't Patch
- Implement application whitelisting to block unauthorized PDF readers
- Deploy endpoint protection with behavioral analysis to detect exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check Adobe Reader version in Help > About Adobe Acrobat Reader DCCheck Version:
On Windows: wmic product where name="Adobe Acrobat Reader DC" get versionVerify Fix Applied:
Verify version is later than affected versions: 21.007.20099, 20.004.30017, or 17.011.30204📡 Detection & Monitoring
Log Indicators:
- Adobe Reader crash logs with memory access violations
- Windows Event Logs showing unexpected process creation from AcroRd32.exe
Network Indicators:
- Unexpected 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"