CVE-2021-44705
📋 TL;DR
CVE-2021-44705 is a use-after-free vulnerability in Adobe Acrobat Reader DC that could allow arbitrary code execution when a user opens a malicious PDF file. This affects users of Adobe Acrobat Reader DC across multiple versions on Windows, macOS, and potentially other platforms where these versions are installed.
💻 Affected Systems
- Adobe Acrobat Reader DC
📦 What is this software?
Acrobat by Adobe
Acrobat by Adobe
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining the same privileges as the current user, potentially leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Malicious code execution leading to credential theft, data exfiltration, or installation of persistent malware on the victim's system.
If Mitigated
Limited impact with proper application sandboxing, exploit mitigations, and user awareness preventing malicious file execution.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious PDF). The vulnerability is in Format event action processing and has been publicly disclosed with technical details.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 21.007.20099 (21.x), 20.004.30017 (20.x), 17.011.30204 (17.x) - update to latest versions beyond these
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 by disabling JavaScript execution which may be required for the vulnerability
Edit > Preferences > JavaScript > Uncheck 'Enable Acrobat JavaScript'
Use Protected View
allOpen untrusted PDFs in Protected View mode to limit potential damage
File > Open > Select 'Protected View' option when opening files
🧯 If You Can't Patch
- Implement application whitelisting to block execution of Adobe Reader if not updated
- Use network segmentation to limit access to systems running vulnerable versions
🔍 How to Verify
Check if Vulnerable:
Check Adobe Reader version via Help > About Adobe Acrobat Reader DC and compare against affected versionsCheck Version:
On Windows: wmic product where name="Adobe Acrobat Reader DC" get versionVerify Fix Applied:
Verify version is updated beyond 21.007.20099, 20.004.30017, or 17.011.30204 depending on your track📡 Detection & Monitoring
Log Indicators:
- Adobe Reader crash logs with exception codes
- Windows Event Logs showing unexpected process termination
Network Indicators:
- Unexpected outbound connections from Adobe Reader process
- Downloads of PDF files from untrusted sources
SIEM Query:
source="*adobe*" AND (event_type="crash" OR exception_code="*" OR process_name="AcroRd32.exe")