CVE-2019-6139
📋 TL;DR
CVE-2019-6139 is a critical remote arbitrary file upload vulnerability in Forcepoint User ID (FUID) server versions up to 1.2. Attackers can exploit this via TCP port 5001 to upload malicious files, potentially leading to remote code execution. Organizations running FUID server versions 1.2 or earlier are affected.
💻 Affected Systems
- Forcepoint User ID (FUID) Server
📦 What is this software?
User Id by Forcepoint
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise through remote code execution, allowing attackers to execute arbitrary commands, steal data, or deploy ransomware.
Likely Case
Remote code execution leading to unauthorized access, data exfiltration, or installation of backdoors on vulnerable FUID servers.
If Mitigated
No impact if port 5001 is properly firewalled or the system is upgraded to version 1.3+.
🎯 Exploit Status
Exploitation requires network access to port 5001 but no authentication. Weaponization is likely given the high CVSS score and RCE potential.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.3 or higher
Vendor Advisory: https://help.forcepoint.com/security/CVE/CVE-2019-6139.html
Restart Required: Yes
Instructions:
1. Download FUID version 1.3 or higher from Forcepoint support portal. 2. Backup current configuration. 3. Install the new version following vendor documentation. 4. Restart the FUID service.
🔧 Temporary Workarounds
Firewall Port 5001
linuxBlock external access to TCP port 5001 using local firewall rules, allowing only loopback interface connections.
iptables -A INPUT -p tcp --dport 5001 -s 127.0.0.1 -j ACCEPT
iptables -A INPUT -p tcp --dport 5001 -j DROP
🧯 If You Can't Patch
- Implement strict network segmentation to isolate FUID servers and block all external access to port 5001.
- Deploy intrusion detection/prevention systems to monitor and block suspicious file upload attempts on port 5001.
🔍 How to Verify
Check if Vulnerable:
Check FUID server version via admin interface or configuration files. If version is 1.2 or lower and port 5001 is accessible, the system is vulnerable.Check Version:
Check FUID configuration files or admin console for version information (specific command depends on installation).Verify Fix Applied:
Verify FUID server version is 1.3 or higher and confirm port 5001 is not externally accessible via firewall rules.📡 Detection & Monitoring
Log Indicators:
- Unusual file upload activity on port 5001
- Unexpected process execution following file uploads
- Failed authentication attempts if logging is enabled
Network Indicators:
- External connections to TCP port 5001
- Large or suspicious file transfers on port 5001
SIEM Query:
source_port:5001 AND (event_type:file_upload OR event_type:process_execution)