CVE-2021-40680
📋 TL;DR
This vulnerability allows attackers to perform directory traversal attacks on Artica Proxy by manipulating the filename parameter in the /cgi-bin/main.cgi endpoint. This could enable unauthorized file access, including reading sensitive system files. Affected systems include Artica Proxy versions 4.30.000000 SP206 through SP255 and VMware appliance versions 4.30.000000 through SP273.
💻 Affected Systems
- Artica Proxy
- Artica Proxy VMware Appliance
📦 What is this software?
Web Proxy by Articatech
Web Proxy by Articatech
Web Proxy by Articatech
Web Proxy by Articatech
Web Proxy by Articatech
Web Proxy by Articatech
Web Proxy by Articatech
Web Proxy by Articatech
Web Proxy by Articatech
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through reading sensitive configuration files, credentials, or executing arbitrary code by accessing critical system files.
Likely Case
Unauthorized access to sensitive files containing configuration data, logs, or credentials stored on the proxy server.
If Mitigated
Limited impact with proper network segmentation, file system permissions, and input validation controls in place.
🎯 Exploit Status
Exploitation requires simple HTTP requests with directory traversal sequences in the filename parameter.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after SP255 for standard installation, after SP273 for VMware appliance
Vendor Advisory: http://seclists.org/fulldisclosure/2022/Apr/39
Restart Required: Yes
Instructions:
1. Upgrade to the latest patched version from the Artica Proxy vendor. 2. Apply the update package. 3. Restart the Artica Proxy service. 4. Verify the fix is applied.
🔧 Temporary Workarounds
Web Application Firewall (WAF) Rules
allImplement WAF rules to block directory traversal patterns in HTTP requests.
Depends on specific WAF platform - configure rules to detect and block '../', '..\', and similar traversal sequences in filename parameter
Network Access Control
linuxRestrict access to the vulnerable endpoint to trusted IP addresses only.
iptables -A INPUT -p tcp --dport 80 -s trusted_ip -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s trusted_ip -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Artica Proxy from sensitive systems.
- Deploy additional monitoring and alerting for suspicious file access patterns.
🔍 How to Verify
Check if Vulnerable:
Test by sending a request to /cgi-bin/main.cgi with a filename parameter containing directory traversal sequences (e.g., filename=../../../etc/passwd) and checking if sensitive files are returned.Check Version:
Check Artica Proxy web interface or configuration files for version information, typically in /usr/share/artica-webui or similar installation directories.Verify Fix Applied:
Attempt the same directory traversal test after patching - requests should be rejected or return error messages instead of file contents.📡 Detection & Monitoring
Log Indicators:
- HTTP requests to /cgi-bin/main.cgi with filename parameter containing '../', '..\', or similar traversal patterns
- Unusual file access patterns from web server process
Network Indicators:
- HTTP GET/POST requests to vulnerable endpoint with traversal sequences in parameters
SIEM Query:
source="artica-proxy" AND (url="/cgi-bin/main.cgi" AND (filename="*../*" OR filename="*..\\*"))