CVE-2021-43176
📋 TL;DR
This vulnerability allows attackers to execute arbitrary PHP files on GOautodial servers by manipulating the 'action' parameter in API calls. When combined with CVE-2021-43175, exploitation can occur without authentication. All GOautodial installations prior to October 13, 2021 are affected.
💻 Affected Systems
- GOautodial
📦 What is this software?
Goautodial by Goautodial
Goautodial Api by Goautodial
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing remote code execution, data theft, and lateral movement within the network.
Likely Case
Unauthenticated attackers gain remote code execution, potentially installing backdoors, stealing sensitive data, or disrupting operations.
If Mitigated
With proper network segmentation and access controls, impact limited to the GOautodial application server.
🎯 Exploit Status
Exploitation is straightforward - attackers simply need to craft HTTP requests with malicious action parameters. Public technical details available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Commit 3c3a979 or later (October 13, 2021)
Vendor Advisory: https://github.com/goautodial/goautodial/commit/3c3a979
Restart Required: Yes
Instructions:
1. Update GOautodial to commit 3c3a979 or later. 2. Restart web server (Apache/Nginx). 3. Restart PHP-FPM if applicable. 4. Verify API endpoints are properly secured.
🔧 Temporary Workarounds
Restrict API Access
linuxBlock external access to GOautodial API endpoints using firewall rules
iptables -A INPUT -p tcp --dport 80 -m string --string "/goautodial/api/" --algo bm -j DROP
iptables -A INPUT -p tcp --dport 443 -m string --string "/goautodial/api/" --algo bm -j DROP
Input Validation Web Application Firewall
allImplement WAF rules to block malicious action parameters
ModSecurity rule: SecRule ARGS:action "@rx \.\.|\/|\\" "id:1001,phase:2,deny,status:403,msg:'GOautodial CVE-2021-43176 exploit attempt'
🧯 If You Can't Patch
- Implement strict network segmentation - isolate GOautodial server from internet and other critical systems
- Deploy application-level monitoring and alerting for suspicious API requests containing path traversal patterns
🔍 How to Verify
Check if Vulnerable:
Check if GOautodial version is older than commit 3c3a979. Test by sending API request with action parameter containing path traversal (e.g., action=../../../etc/passwd).Check Version:
cd /var/www/html/goautodial && git log --oneline -1Verify Fix Applied:
Verify commit hash includes 3c3a979. Test that path traversal in action parameter now returns error instead of executing arbitrary PHP files.📡 Detection & Monitoring
Log Indicators:
- Unusual API requests with action parameters containing '../' or similar path traversal sequences
- Multiple failed authentication attempts followed by API calls
- PHP error logs showing file inclusion errors from GOautodial API
Network Indicators:
- HTTP requests to /goautodial/api/ with unusual action parameters
- Traffic spikes to API endpoints from unexpected sources
SIEM Query:
source="web_access.log" AND uri_path="/goautodial/api/" AND (query="*action=*../*" OR query="*action=*..\\*" OR query="*action=*%2e%2e%2f*")