CVE-2020-3763
📋 TL;DR
CVE-2020-3763 is a critical privilege escalation vulnerability in Adobe Acrobat and Reader that allows attackers to write arbitrary files to the system. This affects users running outdated versions of Adobe Acrobat and Reader across multiple release tracks. Successful exploitation could lead to complete system compromise.
💻 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
Full system compromise with administrative privileges, allowing installation of persistent malware, data theft, and lateral movement across networks.
Likely Case
Local privilege escalation leading to malware installation, data exfiltration, or ransomware deployment on affected systems.
If Mitigated
Limited impact with proper application sandboxing, least privilege principles, and network segmentation in place.
🎯 Exploit Status
Requires local access to the system. The vulnerability allows writing arbitrary files, which can be leveraged for privilege escalation through various techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Acrobat DC/Reader DC: 2020.001.20035 or later; Acrobat 2017/Reader 2017: 2020.001.20035 or later; Acrobat 2015/Reader 2015: 2020.001.20035 or later
Vendor Advisory: https://helpx.adobe.com/security/products/acrobat/apsb20-05.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 the latest version. 4. Restart the application and system if prompted.
🔧 Temporary Workarounds
Disable PDF file associations
windowsPrevent Adobe Acrobat/Reader from automatically opening PDF files
Windows: Control Panel > Default Programs > Set Associations > Find .pdf > Change program to another application
Apply least privilege
allRun Adobe Acrobat/Reader with standard user privileges instead of administrative rights
🧯 If You Can't Patch
- Implement application whitelisting to prevent unauthorized executables from running
- Deploy endpoint detection and response (EDR) solutions to monitor for privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check Adobe Acrobat/Reader version: Open application > Help > About Adobe Acrobat/Reader. Compare version against affected ranges.Check Version:
Windows: wmic product where "name like 'Adobe Acrobat%' or name like 'Adobe Reader%'" get versionVerify Fix Applied:
Verify version is 2020.001.20035 or later in Help > About Adobe Acrobat/Reader.📡 Detection & Monitoring
Log Indicators:
- Windows Event Logs: Security logs showing privilege escalation attempts
- Application logs showing unexpected file write operations by Acrobat/Reader processes
Network Indicators:
- Unusual outbound connections from Acrobat/Reader processes
- DNS requests to suspicious domains from PDF-related processes
SIEM Query:
process_name:"AcroRd32.exe" OR process_name:"Acrobat.exe" AND (event_type:"file_write" OR event_type:"privilege_escalation")