CVE-2020-9704
📋 TL;DR
This CVE describes a buffer overflow vulnerability in Adobe Acrobat and Reader that could allow attackers to execute arbitrary code on affected systems. The vulnerability affects multiple versions of Adobe's PDF software across different release tracks. Users who open malicious PDF files with vulnerable versions are at risk.
💻 Affected Systems
- Adobe Acrobat DC
- Adobe Acrobat Reader DC
- Adobe Acrobat 2017
- Adobe Acrobat Reader 2017
- Adobe Acrobat 2015
- Adobe Acrobat Reader 2015
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through arbitrary code execution with the privileges of the current user, potentially leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Local privilege escalation or remote code execution when users open specially crafted malicious PDF files, leading to malware installation or data exfiltration.
If Mitigated
Limited impact with proper application sandboxing, least privilege principles, and security controls preventing malicious PDF execution.
🎯 Exploit Status
Exploitation requires user interaction to open a malicious PDF file. No public exploit code was available at the time of the advisory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Acrobat DC/Reader DC: 2020.009.20075 or later; Acrobat 2017/Reader 2017: 2017.011.30172 or later; Acrobat 2015/Reader 2015: 2015.006.30524 or later
Vendor Advisory: https://helpx.adobe.com/security/products/acrobat/apsb20-48.html
Restart Required: Yes
Instructions:
1. Open Adobe Acrobat or Reader. 2. Navigate to Help > Check for Updates. 3. Follow the prompts to download and install available updates. 4. Restart the application when prompted. 5. Verify the update by checking Help > About Adobe Acrobat/Reader.
🔧 Temporary Workarounds
Disable JavaScript in Adobe Reader
allDisabling JavaScript reduces attack surface and may prevent exploitation of some PDF-based vulnerabilities
Edit > Preferences > JavaScript > Uncheck 'Enable Acrobat JavaScript'
Use Protected View
allEnable Protected View for files from potentially unsafe locations
Edit > Preferences > Security (Enhanced) > Enable Protected View at startup
🧯 If You Can't Patch
- Restrict PDF file handling to trusted sources only and implement application whitelisting
- Use alternative PDF viewers that are not affected by this vulnerability
🔍 How to Verify
Check if Vulnerable:
Check Adobe Acrobat/Reader version against affected version ranges in the advisoryCheck Version:
Help > About Adobe Acrobat/Reader (Windows/macOS GUI)Verify Fix Applied:
Verify installed version is equal to or higher than the patched versions listed in the advisory📡 Detection & Monitoring
Log Indicators:
- Application crashes in Adobe Acrobat/Reader with memory access violations
- Unexpected child processes spawned from Acrobat/Reader
Network Indicators:
- Outbound connections from Acrobat/Reader process to unexpected destinations
- DNS requests for suspicious domains following PDF file opening
SIEM Query:
process_name:"AcroRd32.exe" OR process_name:"Adobe Acrobat" AND (event_id:1000 OR event_id:1001) AND source_name:"Application Error"