CVE-2021-34949
📋 TL;DR
This vulnerability in Foxit PDF Reader allows attackers to read sensitive information from memory by tricking users into opening malicious PDF files. The flaw exists in how annotation objects are processed, enabling out-of-bounds memory reads. All users running vulnerable versions of Foxit PDF Reader are affected.
💻 Affected Systems
- Foxit PDF Reader
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers combine this information disclosure vulnerability with other exploits to achieve arbitrary code execution, potentially compromising the entire system.
Likely Case
Attackers use this vulnerability to leak sensitive information from memory, which could include credentials, encryption keys, or other confidential data.
If Mitigated
With proper controls, the impact is limited to information disclosure without code execution, though sensitive data may still be exposed.
🎯 Exploit Status
Requires user interaction to open malicious file; often chained with other vulnerabilities for full exploitation
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 11.0.1 and later
Vendor Advisory: https://www.foxit.com/support/security-bulletins.html
Restart Required: Yes
Instructions:
1. Download latest version from Foxit website
2. Run installer
3. Restart system
4. Verify version is 11.0.1 or higher
🔧 Temporary Workarounds
Disable PDF Reader in Browser
allPrevent automatic PDF opening in web browsers
Browser-specific settings vary - disable PDF reader plugins
Use Alternative PDF Viewer
allTemporarily use different PDF software until patched
🧯 If You Can't Patch
- Restrict PDF file opening to trusted sources only
- Implement application whitelisting to block Foxit Reader execution
🔍 How to Verify
Check if Vulnerable:
Check Foxit Reader version in Help > AboutCheck Version:
Not applicable - check via GUI in Help > AboutVerify Fix Applied:
Verify version is 11.0.1 or higher in Help > About📡 Detection & Monitoring
Log Indicators:
- Multiple crash reports from Foxit Reader
- Unusual PDF file access patterns
Network Indicators:
- Downloads of PDF files from suspicious sources
SIEM Query:
Process:foxitreader.exe AND (EventID:1000 OR EventID:1001) OR FileExtension:pdf AND SourceIP:(suspicious_ips)