CVE-2020-24430
📋 TL;DR
This CVE describes a use-after-free vulnerability in Adobe Acrobat Reader DC that allows arbitrary code execution when processing malicious JavaScript in PDF files. Attackers can exploit this by tricking users into opening specially crafted PDF documents, potentially gaining control of the affected system. Users of Adobe Acrobat Reader DC versions 2020.012.20048 and earlier, 2020.001.30005 and earlier, or 2017.011.30175 and earlier are affected.
💻 Affected Systems
- Adobe Acrobat Reader DC
📦 What is this software?
Acrobat by Adobe
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining full control of the victim's computer, allowing data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Malware installation leading to data exfiltration, credential theft, or system disruption for individual users who open malicious PDFs.
If Mitigated
Limited impact with proper patching and security controls, potentially only affecting isolated systems with no network access.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious PDF). No public exploit code was available at disclosure time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2020.012.20056, 2020.001.30006, 2017.011.30176 or later
Vendor Advisory: https://helpx.adobe.com/security/products/acrobat/apsb20-67.html
Restart Required: Yes
Instructions:
1. Open Adobe Acrobat Reader DC. 2. Go to Help > Check for Updates. 3. Follow prompts to install available updates. 4. Restart the application. Alternatively, download and install the latest version from Adobe's website.
🔧 Temporary Workarounds
Disable JavaScript in Adobe Reader
allPrevents JavaScript execution in PDF files, which mitigates this vulnerability since exploitation requires JavaScript.
1. Open Adobe Reader. 2. Go to Edit > Preferences. 3. Select JavaScript. 4. Uncheck 'Enable Acrobat JavaScript'. 5. Click OK.
Use Protected View
allOpen PDFs in Protected View mode to restrict JavaScript execution and other potentially dangerous actions.
1. Open Adobe Reader. 2. Go to Edit > Preferences. 3. Select Security (Enhanced). 4. Check 'Enable Protected View at startup'. 5. Configure Protected View settings as needed.
🧯 If You Can't Patch
- Disable JavaScript in Adobe Reader settings to prevent exploitation
- Use application whitelisting to block execution of malicious payloads
- Implement network segmentation to limit lateral movement if compromised
- Educate users to avoid opening PDFs from untrusted sources
🔍 How to Verify
Check if Vulnerable:
Check Adobe Reader version: Open Adobe Reader, go to Help > About Adobe Acrobat Reader DC. If version is 2020.012.20048 or earlier, 2020.001.30005 or earlier, or 2017.011.30175 or earlier, the system is vulnerable.Check Version:
On Windows: wmic product where name="Adobe Acrobat Reader DC" get version. On macOS: /Applications/Adobe\ Acrobat\ Reader\ DC/Reader/Contents/Info.plist | grep -A1 CFBundleShortVersionStringVerify Fix Applied:
Verify Adobe Reader version is 2020.012.20056 or later, 2020.001.30006 or later, or 2017.011.30176 or later.📡 Detection & Monitoring
Log Indicators:
- Adobe Reader crash logs with memory access violations
- Windows Event Logs showing unexpected process creation from AcroRd32.exe
- Antivirus alerts for malicious PDF files
Network Indicators:
- Outbound connections from Adobe Reader process to suspicious IPs
- DNS requests for known malicious domains following PDF opening
SIEM Query:
source="*acrobat*" OR process="AcroRd32.exe" AND (event_type="crash" OR parent_process="explorer.exe" AND child_process="cmd.exe")