CVE-2020-8853
📋 TL;DR
This vulnerability in Foxit PhantomPDF allows remote attackers to execute arbitrary code by tricking users into opening malicious HTML files or visiting malicious web pages. The flaw exists in the HTML-to-PDF conversion feature where improper data validation leads to memory corruption. Users of affected Foxit PhantomPDF versions are at risk.
💻 Affected Systems
- Foxit PhantomPDF
📦 What is this software?
Phantompdf by Foxitsoftware
Reader by Foxitsoftware
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining full control of the victim's computer, potentially leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Attacker executes code with user privileges, potentially installing malware, stealing sensitive documents, or establishing persistence on the system.
If Mitigated
If proper controls like application sandboxing or memory protection are in place, exploitation may be limited to application crash or denial of service.
🎯 Exploit Status
Exploitation requires user interaction but the vulnerability is publicly documented and has been assigned ZDI-CAN-9591 identifier. The CVSS score of 7.8 indicates relatively straightforward exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 9.7.1.29511 or later
Vendor Advisory: https://www.foxitsoftware.com/support/security-bulletins.php
Restart Required: Yes
Instructions:
1. Download the latest version from Foxit's official website. 2. Run the installer. 3. Follow installation prompts. 4. Restart the computer after installation completes.
🔧 Temporary Workarounds
Disable HTML-to-PDF conversion
windowsPrevent the vulnerable feature from being used by disabling HTML file processing in Foxit PhantomPDF
Application sandboxing
windowsRun Foxit PhantomPDF in a sandboxed environment to limit potential damage from exploitation
🧯 If You Can't Patch
- Implement application whitelisting to prevent execution of unauthorized code
- Use network segmentation to isolate systems running vulnerable software from critical assets
🔍 How to Verify
Check if Vulnerable:
Check Foxit PhantomPDF version in Help > About. If version is 9.7.0.29478 or earlier, the system is vulnerable.Check Version:
Not applicable - check via GUI in Help > About menuVerify Fix Applied:
Verify version is 9.7.1.29511 or later in Help > About menu.📡 Detection & Monitoring
Log Indicators:
- Unexpected process crashes of Foxit PhantomPDF
- Unusual network connections originating from Foxit processes
- Creation of suspicious files or registry entries by Foxit
Network Indicators:
- Outbound connections to suspicious IPs from Foxit processes
- DNS requests for malicious domains
SIEM Query:
process_name:"FoxitPhantomPDF.exe" AND (event_type:crash OR network_connection:malicious_ip)