CVE-2022-26265
📋 TL;DR
CVE-2022-26265 is a critical remote command execution vulnerability in Contao Managed Edition v1.5.0 that allows attackers to execute arbitrary commands on the server via the php_cli parameter. This affects all organizations running the vulnerable version of Contao Managed Edition. Successful exploitation gives attackers complete control over the affected system.
💻 Affected Systems
- Contao Managed Edition
📦 What is this software?
Contao by Contao
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise allowing attackers to execute arbitrary commands, install malware, exfiltrate data, pivot to other systems, and establish persistent access.
Likely Case
Attackers gain shell access to the web server, allowing them to read sensitive files, modify website content, and potentially access backend databases.
If Mitigated
With proper network segmentation and least privilege, impact could be limited to the web application server only.
🎯 Exploit Status
Public proof-of-concept code exists and demonstrates trivial exploitation. No authentication required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 1.5.1 or later
Vendor Advisory: https://contao.org/en/security-advisories/
Restart Required: No
Instructions:
1. Backup your Contao installation and database. 2. Update Contao Managed Edition to version 1.5.1 or later. 3. Verify the update completed successfully. 4. Test application functionality.
🔧 Temporary Workarounds
Input Validation Filter
allAdd input validation to filter or block php_cli parameter containing command injection patterns
# Add to application code to sanitize php_cli parameter
# Example: filter_var($php_cli, FILTER_SANITIZE_STRING)
Web Application Firewall Rule
allBlock requests containing suspicious php_cli parameter values
# WAF rule to block php_cli parameter with command injection patterns
# Example ModSecurity rule: SecRule ARGS:php_cli "[;|&`$()]" "deny,status:403"
🧯 If You Can't Patch
- Immediately isolate the affected system from the internet and restrict network access
- Implement strict input validation for all user-controlled parameters, especially php_cli
🔍 How to Verify
Check if Vulnerable:
Check Contao version in admin panel or via composer show contao/managed-edition. If version is exactly 1.5.0, system is vulnerable.Check Version:
composer show contao/managed-edition | grep versionsVerify Fix Applied:
Verify version is 1.5.1 or later using composer show contao/managed-edition or check admin panel version.📡 Detection & Monitoring
Log Indicators:
- Unusual php_cli parameter values in web logs
- Commands like whoami, id, ls, cat in URL parameters
- Multiple failed exploitation attempts
Network Indicators:
- HTTP requests with php_cli parameter containing shell metacharacters
- Outbound connections from web server to unexpected destinations
SIEM Query:
source="web_logs" AND (php_cli="*;*" OR php_cli="*|*" OR php_cli="*`*" OR php_cli="*$(*)")