CVE-2020-3805
📋 TL;DR
This CVE describes a use-after-free vulnerability in Adobe Acrobat and Reader that could allow attackers to execute arbitrary code on affected systems. The vulnerability affects multiple versions across different release tracks. Successful exploitation requires a user to open a malicious PDF file.
💻 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 with attacker gaining full control of the affected system, potentially leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Local privilege escalation or remote code execution when a user opens a malicious PDF document, leading to malware installation or data exfiltration.
If Mitigated
Limited impact with proper application sandboxing, memory protection mechanisms, and user awareness preventing malicious PDF execution.
🎯 Exploit Status
Exploitation requires user interaction (opening a malicious PDF). Memory corruption vulnerabilities in PDF readers are commonly exploited in targeted attacks.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2020.006.20042, 2017.011.30166, 2015.006.30518 or later
Vendor Advisory: https://helpx.adobe.com/security/products/acrobat/apsb20-13.html
Restart Required: Yes
Instructions:
1. Open Adobe Acrobat or Reader. 2. Go to Help > Check for Updates. 3. Follow prompts to download and install the latest version. 4. Restart the application when prompted.
🔧 Temporary Workarounds
Disable JavaScript in Adobe Reader
allPrevents JavaScript-based exploitation vectors that might be used in conjunction with this vulnerability
Edit > Preferences > JavaScript > Uncheck 'Enable Acrobat JavaScript'
Use Protected View
allOpen PDFs in Protected View mode to limit potential damage from malicious files
File > Properties > Security > Enable Protected View for all files from potentially unsafe locations
🧯 If You Can't Patch
- Restrict PDF file handling to alternative PDF readers that are not vulnerable
- Implement application whitelisting to block execution of vulnerable Adobe Reader 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 like 'Adobe Acrobat%'" get versionVerify Fix Applied:
Verify version is 2020.006.20042 or later, 2017.011.30166 or later, or 2015.006.30518 or later📡 Detection & Monitoring
Log Indicators:
- Application crashes in Adobe Reader/Acrobat
- Unusual process creation from Adobe Reader
- Memory access violation events
Network Indicators:
- Unexpected outbound connections from Adobe Reader process
- DNS requests for suspicious domains following PDF opening
SIEM Query:
source="*adobe*" AND (event_id=1000 OR event_id=1001) AND process_name="AcroRd32.exe" OR process_name="Acrobat.exe"