CVE-2016-9023
📋 TL;DR
CVE-2016-9023 is an improper input validation vulnerability in Exponent CMS's cron/find_help.php script that allows remote attackers to execute arbitrary code. This affects all Exponent CMS installations before version 2.6.0. The vulnerability can be exploited without authentication.
💻 Affected Systems
- Exponent CMS
📦 What is this software?
Exponent Cms by Exponentcms
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, and potential lateral movement within the network.
Likely Case
Remote code execution allowing attackers to deface websites, install malware, or steal sensitive data from the CMS database.
If Mitigated
Attackers can probe the system but cannot execute code due to proper input validation and sanitization.
🎯 Exploit Status
The vulnerability is in a publicly accessible script with no authentication required, making exploitation straightforward.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.6.0
Vendor Advisory: https://exponentcms.lighthouseapp.com/projects/61783/changesets/a8efd9ca71fc9b8b843ad0910d435d237482ee31
Restart Required: No
Instructions:
1. Backup your current Exponent CMS installation and database. 2. Download Exponent CMS version 2.6.0 or later from the official repository. 3. Replace the vulnerable cron/find_help.php file with the patched version. 4. Verify the fix by checking that input validation is properly implemented.
🔧 Temporary Workarounds
Remove vulnerable script
linuxDelete or rename the cron/find_help.php file to prevent exploitation.
rm /path/to/exponent/cron/find_help.php
Restrict access via web server
allConfigure web server to block access to the cron/find_help.php file.
<Location "/cron/find_help.php">
Order deny,allow
Deny from all
</Location>
🧯 If You Can't Patch
- Implement a web application firewall (WAF) with rules to block malicious input to cron/find_help.php.
- Isolate the Exponent CMS instance from critical network segments and monitor for suspicious activity.
🔍 How to Verify
Check if Vulnerable:
Check if cron/find_help.php exists and examine its code for proper input validation. If the file exists and your Exponent CMS version is below 2.6.0, you are vulnerable.Check Version:
Check the version.php file in your Exponent CMS installation or look at the admin panel version information.Verify Fix Applied:
Verify that the cron/find_help.php file has been updated with proper input validation checks or removed. Test by attempting to send malicious input to the script.📡 Detection & Monitoring
Log Indicators:
- Unusual POST or GET requests to cron/find_help.php with suspicious parameters
- System commands being executed from the web server process
Network Indicators:
- HTTP requests to cron/find_help.php containing shell commands or encoded payloads
SIEM Query:
source="web_server_logs" AND uri="/cron/find_help.php" AND (param="*" OR param="|*" OR param="`*" OR param="$(*")🔗 References
- https://exponentcms.lighthouseapp.com/projects/61783/changesets/a8efd9ca71fc9b8b843ad0910d435d237482ee31
- https://github.com/exponentcms/exponent-cms/commit/a8efd9ca71fc9b8b843ad0910d435d237482ee31
- https://exponentcms.lighthouseapp.com/projects/61783/changesets/a8efd9ca71fc9b8b843ad0910d435d237482ee31
- https://github.com/exponentcms/exponent-cms/commit/a8efd9ca71fc9b8b843ad0910d435d237482ee31
