CVE-2019-7412
📋 TL;DR
This vulnerability in the PS PHPCaptcha WordPress plugin allows attackers to bypass input sanitization, potentially leading to denial of service attacks. It affects WordPress sites using PS PHPCaptcha plugin versions before 1.2.0. The high CVSS score indicates critical severity requiring immediate attention.
💻 Affected Systems
- PS PHPCaptcha WordPress Plugin
📦 What is this software?
Ps Phpcaptcha Wp by Ps Phpcaptcha Wp Project
⚠️ Risk & Real-World Impact
Worst Case
Complete website unavailability through resource exhaustion or service disruption
Likely Case
Temporary service degradation or website downtime
If Mitigated
Minimal impact with proper input validation and rate limiting
🎯 Exploit Status
Exploitation requires no authentication and is straightforward due to improper input handling
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.2.0
Vendor Advisory: https://wordpress.org/plugins/ps-phpcaptcha/#developers
Restart Required: No
Instructions:
1. Log into WordPress admin panel
2. Navigate to Plugins → Installed Plugins
3. Find PS PHPCaptcha
4. Click 'Update Now' if available
5. If no update available, deactivate and delete plugin
6. Install version 1.2.0 or later from WordPress repository
🔧 Temporary Workarounds
Disable PS PHPCaptcha Plugin
allTemporarily disable the vulnerable plugin until patched
wp plugin deactivate ps-phpcaptcha
Implement Web Application Firewall Rules
allAdd WAF rules to block suspicious input patterns
🧯 If You Can't Patch
- Remove PS PHPCaptcha plugin completely and use alternative captcha solution
- Implement rate limiting and input validation at web server level
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin → Plugins → PS PHPCaptcha → Version numberCheck Version:
wp plugin get ps-phpcaptcha --field=versionVerify Fix Applied:
Confirm plugin version is 1.2.0 or higher in WordPress admin📡 Detection & Monitoring
Log Indicators:
- Unusual high volume of requests to captcha endpoints
- Multiple failed captcha validations
- Resource exhaustion alerts
Network Indicators:
- Spike in traffic to /wp-content/plugins/ps-phpcaptcha/ paths
- Abnormal request patterns bypassing captcha
SIEM Query:
source="wordpress.log" AND "ps-phpcaptcha" AND (status=500 OR response_time>5000)🔗 References
- https://metamorfosec.com/Files/Advisories/METS-2019-003-Denial_of_Service_in_PS_PHPCaptcha_WP_before_v1.2.0.txt
- https://wordpress.org/plugins/ps-phpcaptcha/#developers
- https://metamorfosec.com/Files/Advisories/METS-2019-003-Denial_of_Service_in_PS_PHPCaptcha_WP_before_v1.2.0.txt
- https://wordpress.org/plugins/ps-phpcaptcha/#developers
