CVE-2023-26369
📋 TL;DR
This CVE describes an out-of-bounds write vulnerability in Adobe Acrobat Reader that could allow arbitrary code execution when a user opens a malicious PDF file. The vulnerability affects multiple versions of Acrobat Reader DC and Acrobat Reader 2020. Successful exploitation requires user interaction to open a malicious file.
💻 Affected Systems
- Adobe Acrobat Reader DC
- Adobe Acrobat Reader 2020
📦 What is this software?
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 persistent backdoor installation.
Likely Case
Malicious code execution in the context of the current user, allowing attackers to steal credentials, install malware, or pivot to other systems on the network.
If Mitigated
Limited impact with proper application sandboxing and user privilege restrictions, potentially containing the exploit to the Acrobat process only.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file). CISA has added this to their Known Exploited Vulnerabilities catalog indicating active exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Acrobat Reader DC: 23.003.20284 or later; Acrobat Reader 2020: 20.005.30516 or later
Vendor Advisory: https://helpx.adobe.com/security/products/acrobat/apsb23-34.html
Restart Required: Yes
Instructions:
1. Open Adobe Acrobat Reader. 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
allDisabling JavaScript can prevent exploitation of many 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 for all files from potentially unsafe locations
🧯 If You Can't Patch
- Implement application whitelisting to block execution of unauthorized PDF readers
- Deploy endpoint detection and response (EDR) solutions to monitor for suspicious PDF reader behavior
🔍 How to Verify
Check if Vulnerable:
Check Adobe Acrobat Reader version via Help > About Adobe Acrobat Reader DCCheck Version:
On Windows: wmic product where name="Adobe Acrobat Reader DC" get versionVerify Fix Applied:
Verify version is 23.003.20284 or later for DC, or 20.005.30516 or later for 2020 version📡 Detection & Monitoring
Log Indicators:
- Unusual process creation from AcroRd32.exe or Acrobat.exe
- Multiple failed PDF file openings
- Suspicious child processes spawned from PDF reader
Network Indicators:
- Outbound connections from PDF reader to suspicious IPs
- DNS requests for known malicious domains from PDF reader process
SIEM Query:
Process Creation where ParentImage contains "AcroRd32.exe" or ParentImage contains "Acrobat.exe" and CommandLine contains suspicious patterns