CVE-2021-38563
📋 TL;DR
This vulnerability in Foxit PDF software allows attackers to trigger memory corruption through malformed PDF files, potentially leading to remote code execution. It affects all users of Foxit PDF Reader and PDF Editor versions before 11.0.1. The high CVSS score indicates critical severity requiring immediate attention.
💻 Affected Systems
- Foxit PDF Reader
- Foxit PDF Editor
📦 What is this software?
Pdf Editor by Foxitsoftware
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with SYSTEM/root privileges, allowing complete system compromise and data exfiltration.
Likely Case
Application crash leading to denial of service, with potential for information disclosure through memory leaks.
If Mitigated
Application crash with no data loss if proper sandboxing and memory protections are enabled.
🎯 Exploit Status
Exploitation requires user interaction to open a malicious PDF file. No authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 11.0.1 and later
Vendor Advisory: https://www.foxitsoftware.com/support/security-bulletins.php
Restart Required: Yes
Instructions:
1. Open Foxit software. 2. Go to Help > Check for Updates. 3. Follow prompts to install version 11.0.1 or later. 4. Restart computer after installation.
🔧 Temporary Workarounds
Disable JavaScript in Foxit
allPrevents some exploitation vectors by disabling JavaScript execution in PDF files
File > Preferences > JavaScript > Uncheck 'Enable JavaScript'
Use Protected View
allOpen PDFs in protected/sandboxed mode to limit potential damage
File > Preferences > Trust Manager > Check 'Enable Safe Reading Mode'
🧯 If You Can't Patch
- Block PDF files at network perimeter using content filtering
- Use alternative PDF readers that are not vulnerable
🔍 How to Verify
Check if Vulnerable:
Check Foxit version: Open Foxit > Help > About Foxit Reader/Editor. If version is below 11.0.1, you are vulnerable.Check Version:
On Windows: wmic product where "name like 'Foxit%'" get versionVerify Fix Applied:
Verify version is 11.0.1 or higher in Help > About, then test opening known safe PDF files.📡 Detection & Monitoring
Log Indicators:
- Application crashes in Windows Event Logs
- Unexpected memory access errors
- Foxit process termination with error codes
Network Indicators:
- PDF file downloads from suspicious sources
- Multiple PDF files with similar hash patterns
SIEM Query:
source="Windows Security" AND event_id=1000 AND process_name="Foxit*.exe" AND (exception_code=0xc0000005 OR exception_code=0xc0000409)