CVE-2020-27860
📋 TL;DR
CVE-2020-27860 is a remote code execution vulnerability in Foxit Reader that allows attackers to execute arbitrary code by tricking users into opening malicious PDF files or visiting malicious web pages. The vulnerability exists in the XFA template processing component due to improper validation of user-supplied data, leading to an out-of-bounds write. Users of Foxit Reader 10.0.1.35811 and potentially other versions are affected.
💻 Affected Systems
- Foxit Reader
📦 What is this software?
Foxit Reader by Foxitsoftware
Phantompdf by Foxitsoftware
Phantompdf by Foxitsoftware
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining the same privileges as the current user, potentially leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Malware installation on individual workstations, credential theft, or data exfiltration from the compromised system.
If Mitigated
Limited impact with proper application sandboxing, endpoint protection, and user awareness preventing successful exploitation.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file or visiting malicious page). The vulnerability was disclosed through ZDI-CAN-11727 and has public technical details.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 10.1.0.37527 or later
Vendor Advisory: https://www.foxitsoftware.com/support/security-bulletins.html
Restart Required: No
Instructions:
1. Open Foxit Reader. 2. Go to Help > Check for Updates. 3. Follow prompts to install latest version. 4. Alternatively, download and install latest version from Foxit website.
🔧 Temporary Workarounds
Disable JavaScript in Foxit Reader
allPrevents exploitation vectors that rely on JavaScript execution
Open Foxit Reader > File > Preferences > Trust Manager > uncheck 'Enable JavaScript'
Use Protected View
allOpens files in sandboxed mode to limit potential damage
Open Foxit Reader > File > Preferences > Trust Manager > check 'Enable Safe Reading Mode'
🧯 If You Can't Patch
- Replace Foxit Reader with alternative PDF viewers that are not vulnerable
- Implement application whitelisting to block execution of Foxit Reader
🔍 How to Verify
Check if Vulnerable:
Check Foxit Reader version in Help > About Foxit Reader. If version is 10.0.1.35811 or earlier, system is vulnerable.Check Version:
On Windows: wmic product where name="Foxit Reader" get versionVerify Fix Applied:
Verify version is 10.1.0.37527 or later in Help > About Foxit Reader.📡 Detection & Monitoring
Log Indicators:
- Process creation events from Foxit Reader with suspicious command-line arguments
- Crash reports from Foxit Reader with memory corruption indicators
Network Indicators:
- Downloads of PDF files from untrusted sources followed by Foxit Reader execution
SIEM Query:
source="*" (process_name="FoxitReader.exe" OR process_name="Foxit Reader") AND (event_id=1 OR event_id=4688) AND command_line="*.pdf"