CVE-2020-9693
📋 TL;DR
This CVE describes an out-of-bounds write vulnerability in Adobe Acrobat and Reader that could allow attackers to execute arbitrary code on affected systems. Successful exploitation could lead to complete system compromise. Users of vulnerable Adobe PDF software versions are affected.
💻 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, data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Malicious PDF files delivered via phishing or compromised websites lead to malware installation and data exfiltration.
If Mitigated
With proper patching and security controls, impact is limited to failed exploitation attempts with no system compromise.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious PDF), but no authentication needed. ZDI advisory suggests weaponization is likely given the nature of PDF vulnerabilities.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Acrobat DC/Reader DC: 2020.009.20075 or later; Acrobat/Reader 2017: 2017.011.30172 or later; Acrobat/Reader 2015: 2015.006.30524 or later
Vendor Advisory: https://helpx.adobe.com/security/products/acrobat/apsb20-48.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. Alternatively, download latest version from Adobe website.
🔧 Temporary Workarounds
Disable JavaScript in Adobe Reader
allDisabling JavaScript reduces attack surface as many PDF exploits use JavaScript payloads
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
- Restrict PDF file handling to sandboxed environments or alternative PDF viewers
- Implement application whitelisting to block unauthorized code execution
🔍 How to Verify
Check if Vulnerable:
Check Adobe Acrobat/Reader version via Help > About Adobe Acrobat/Reader and compare with affected versions listCheck Version:
On Windows: wmic product where "name like 'Adobe Acrobat%'" get version; On macOS: /Applications/Adobe\ Acrobat\ Reader\ DC.app/Contents/Info.plist | grep -A1 CFBundleShortVersionStringVerify Fix Applied:
Verify version is updated to patched versions: 2020.009.20075+, 2020.001.30003+, 2017.011.30172+, or 2015.006.30524+📡 Detection & Monitoring
Log Indicators:
- Adobe Acrobat/Reader crash logs with memory access violations
- Windows Event Logs showing application crashes (Event ID 1000)
- Unexpected child processes spawned from AcroRd32.exe or Acrobat.exe
Network Indicators:
- Outbound connections from Adobe processes to unknown IPs post-PDF opening
- DNS requests for suspicious domains following PDF file access
SIEM Query:
source="*acrobat*" OR process="AcroRd32.exe" OR process="Acrobat.exe" AND (event_type="crash" OR parent_process!="explorer.exe")