CVE-2021-4466
📋 TL;DR
CVE-2021-4466 is an authenticated remote code execution vulnerability in IPCop firewall software. Authenticated attackers can inject shell commands through the email password field to execute arbitrary operating system commands with web interface privileges. This affects all IPCop users running versions up to 2.1.9.
💻 Affected Systems
- IPCop
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise allowing attacker to install persistent backdoors, exfiltrate all network data, pivot to internal networks, and disable firewall protections.
Likely Case
Attacker gains root-level access to the firewall, enabling network traffic interception, credential theft, and deployment of additional malware.
If Mitigated
With proper network segmentation and access controls, impact limited to the firewall device itself without lateral movement.
🎯 Exploit Status
Exploit requires authenticated access but is trivial to execute once credentials are obtained. Public exploit code available on Exploit-DB.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: IPCop 2.1.10 or later
Vendor Advisory: https://www.ipcop.org/
Restart Required: Yes
Instructions:
1. Backup current configuration. 2. Download IPCop 2.1.10 or later from official site. 3. Perform upgrade following vendor documentation. 4. Restart system. 5. Verify email configuration functionality.
🔧 Temporary Workarounds
Disable email configuration access
linuxRemove or restrict access to email configuration interface for non-admin users
# Modify web interface access controls
# Restrict /cgi-bin/email.cgi access in web server configuration
Network segmentation
linuxRestrict access to IPCop admin interface to trusted management networks only
# Add firewall rules to restrict admin interface access
iptables -A INPUT -p tcp --dport 445 -s TRUSTED_NETWORK -j ACCEPT
iptables -A INPUT -p tcp --dport 445 -j DROP
🧯 If You Can't Patch
- Implement strict access controls to limit who can authenticate to the web interface
- Monitor for unusual command execution patterns and shell metacharacters in email configuration logs
🔍 How to Verify
Check if Vulnerable:
Check IPCop version via web interface or command line. Versions 2.1.9 and earlier are vulnerable.Check Version:
cat /etc/ipcop/version or check via web interface System → StatusVerify Fix Applied:
Verify version is 2.1.10 or later. Test email configuration with shell metacharacters to ensure they are properly sanitized.📡 Detection & Monitoring
Log Indicators:
- Unusual commands in web server logs related to email.cgi
- Shell metacharacters in POST requests to email configuration
- Unexpected process execution from web server user
Network Indicators:
- Unusual outbound connections from firewall device
- Unexpected SSH or reverse shell connections originating from firewall
SIEM Query:
source="ipcop_web_logs" AND (uri="/cgi-bin/email.cgi" AND (POST_data CONTAINS "|" OR POST_data CONTAINS ";" OR POST_data CONTAINS "`" OR POST_data CONTAINS "$"))