CVE-2024-39425
📋 TL;DR
This CVE describes a Time-of-check Time-of-use (TOCTOU) race condition vulnerability in Adobe Acrobat Reader that could allow local attackers to escalate privileges. The vulnerability affects users running specific versions of Acrobat Reader on Windows systems. Exploitation requires local low-privilege access and has high attack complexity.
💻 Affected Systems
- Adobe Acrobat Reader DC
- Adobe Acrobat Reader
📦 What is this software?
Acrobat by Adobe
Acrobat by Adobe
⚠️ Risk & Real-World Impact
Worst Case
An attacker with local low-privilege access could exploit this race condition to execute arbitrary code with SYSTEM/administrator privileges, potentially gaining full control of the affected system.
Likely Case
In most real-world scenarios, this would allow a malicious user or malware already present on the system to elevate privileges from standard user to administrator, enabling persistence, lateral movement, or disabling security controls.
If Mitigated
With proper controls like least privilege access, application whitelisting, and regular patching, the impact is limited as attackers would need to bypass multiple security layers to exploit this local vulnerability.
🎯 Exploit Status
Exploitation requires local access and precise timing to win the race condition. No public proof-of-concept has been disclosed as of the advisory date.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Update to version 20.005.30637 or later for Acrobat Reader DC, or version 24.002.20966 or later for Acrobat Reader
Vendor Advisory: https://helpx.adobe.com/security/products/acrobat/apsb24-57.html
Restart Required: Yes
Instructions:
1. Open Adobe Acrobat 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 Adobe Acrobat Reader automatic updates
windowsPrevents potential exploitation through update mechanisms while waiting for patch deployment
reg add "HKLM\SOFTWARE\Policies\Adobe\Acrobat Reader\DC\FeatureLockDown" /v bUpdater /t REG_DWORD /d 0 /f
Restrict execution to trusted users
windowsLimit Acrobat Reader execution to only necessary users through group policy or application control
🧯 If You Can't Patch
- Implement least privilege access controls to limit users who can run Acrobat Reader
- Deploy application whitelisting to prevent unauthorized execution or modification of Acrobat Reader binaries
🔍 How to Verify
Check if Vulnerable:
Check Adobe Acrobat Reader version by opening the application and navigating to Help > About Adobe Acrobat Reader DCCheck Version:
wmic product where "name like 'Adobe Acrobat Reader%'" get versionVerify Fix Applied:
Verify the version number is 20.005.30637 or higher for Acrobat Reader DC, or 24.002.20966 or higher for Acrobat Reader📡 Detection & Monitoring
Log Indicators:
- Unusual process creation from Acrobat Reader binaries
- Multiple rapid file access attempts to Acrobat Reader directories
- Privilege escalation events following Acrobat Reader execution
Network Indicators:
- No network indicators as this is a local privilege escalation vulnerability
SIEM Query:
EventID=4688 AND (ProcessName LIKE '%AcroRd32.exe%' OR ProcessName LIKE '%Acrobat.exe%') AND NewProcessName LIKE '%cmd.exe%' OR NewProcessName LIKE '%powershell.exe%'