CVE-2020-3799
📋 TL;DR
This CVE describes a critical stack-based buffer overflow vulnerability in Adobe Acrobat and Reader that allows attackers to execute arbitrary code on affected systems. Users running vulnerable versions of Adobe Acrobat or Reader across multiple release tracks are at risk. Successful exploitation typically occurs when a user opens 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 over the victim's computer, enabling data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Malicious PDF files delivered via phishing emails or compromised websites lead to remote code execution, often resulting in malware installation or credential theft.
If Mitigated
With proper patching and security controls, the risk is limited to isolated incidents that can be contained through endpoint protection and user awareness.
🎯 Exploit Status
Exploitation requires user interaction (opening a malicious PDF) but no authentication. Buffer overflow vulnerabilities in PDF readers are commonly weaponized in phishing campaigns.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Acrobat DC/Reader DC: 2020.006.20042 or later; Acrobat 2017/Reader 2017: 2017.011.30166 or later; Acrobat 2015/Reader 2015: 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. Navigate to Help > Check for Updates. 3. Follow prompts to download and install available updates. 4. Restart the application when prompted. 5. Verify update by checking Help > About Adobe Acrobat/Reader.
🔧 Temporary Workarounds
Disable JavaScript in Adobe Reader
allDisabling JavaScript reduces attack surface as many PDF exploits rely on JavaScript execution
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
- Implement application whitelisting to block unauthorized PDF readers
- Deploy network segmentation to isolate PDF processing systems
🔍 How to Verify
Check if Vulnerable:
Check Adobe Acrobat/Reader version via Help > About Adobe Acrobat/Reader and compare against affected versionsCheck Version:
On Windows: wmic product where "name like 'Adobe Acrobat%'" get version; On macOS: /usr/bin/mdls -name kMDItemVersion /Applications/Adobe\ Acrobat*.appVerify Fix Applied:
Verify version is at or above patched versions: 2020.006.20042, 2017.011.30166, or 2015.006.30518📡 Detection & Monitoring
Log Indicators:
- Adobe crash reports with exception codes (e.g., 0xC0000005)
- Windows Event Logs showing Acrobat/Reader process crashes
- Unexpected child processes spawned from Acrobat/Reader
Network Indicators:
- Outbound connections from Acrobat/Reader to suspicious IPs
- DNS requests for known exploit domains following PDF opening
SIEM Query:
source="*acrobat*" OR source="*reader*" AND (event_id=1000 OR "crash" OR "exception")