CVE-2020-21486
📋 TL;DR
CVE-2020-21486 is an SQL injection vulnerability in PHPOK v.5.4 that allows remote attackers to extract sensitive information from the database. The vulnerability exists in the _userlist function within the framerwork/phpok_call.php file. Any PHPOK v.5.4 installation with this vulnerable code is affected.
💻 Affected Systems
- PHPOK CMS
📦 What is this software?
Phpok by Phpok
⚠️ Risk & Real-World Impact
Worst Case
Complete database compromise including user credentials, sensitive application data, and potential privilege escalation leading to full system takeover.
Likely Case
Extraction of user data, configuration details, and potentially authentication information from the database.
If Mitigated
Limited information disclosure if database permissions are properly restricted and input validation is enforced.
🎯 Exploit Status
The GitHub issue shows proof-of-concept exploitation details. SQL injection vulnerabilities are commonly weaponized in automated attacks.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version after v.5.4 (check latest release)
Vendor Advisory: https://github.com/qinggan/phpok/issues/8
Restart Required: No
Instructions:
1. Upgrade to the latest PHPOK version. 2. If upgrading is not possible, manually patch the framerwork/phpok_call.php file by implementing proper input validation and parameterized queries in the _userlist function.
🔧 Temporary Workarounds
Input Validation Filter
allAdd input validation to filter malicious SQL characters before processing
# Add input sanitization in framerwork/phpok_call.php
# Example: $input = preg_replace('/[^a-zA-Z0-9_]/', '', $_GET['param']);
WAF Rule
allImplement web application firewall rules to block SQL injection patterns
# ModSecurity rule example:
# SecRule ARGS "(?i:(union.*select|select.*from))" "phase:2,deny,id:1001"
🧯 If You Can't Patch
- Implement strict input validation and parameterized queries in all database interactions
- Restrict database user permissions to read-only where possible and implement network segmentation
🔍 How to Verify
Check if Vulnerable:
Check if framerwork/phpok_call.php contains the vulnerable _userlist function without proper input validation. Test with SQL injection payloads against userlist endpoints.Check Version:
# Check PHPOK version in admin panel or look for version.php file
# grep -r "5.4" /path/to/phpok/installation/Verify Fix Applied:
Verify that parameterized queries are used in the _userlist function and test with SQL injection payloads to confirm they're blocked.📡 Detection & Monitoring
Log Indicators:
- Unusual SQL queries in application logs
- Multiple failed login attempts or database errors
- Requests to phpok_call.php with SQL keywords in parameters
Network Indicators:
- HTTP requests containing SQL injection patterns (UNION SELECT, etc.)
- Unusual database connection patterns from web servers
SIEM Query:
source="web_logs" AND ("phpok_call.php" OR "_userlist") AND ("union" OR "select" OR "from" OR "where" OR "--")