CVE-2020-37151: phpMyChat Plus SQL Injection Vulnerability

CVE-2020-37151 Overview

phpMyChat Plus 1.98 contains a SQL injection vulnerability in the deluser.php page through the pmc_username parameter that allows attackers to manipulate database queries. Attackers can exploit boolean-based, error-based, and time-based blind SQL injection techniques to extract sensitive database information by crafting malicious payloads in the username field.

Critical Impact

This SQL injection vulnerability allows unauthenticated remote attackers to extract sensitive database contents, potentially including user credentials, chat histories, and other confidential information stored in the phpMyChat Plus database.

Affected Products

• phpMyChat Plus version 1.98

Discovery Timeline

• 2026-02-05 - CVE-2020-37151 published to NVD
• 2026-02-05 - Last updated in NVD database

Technical Details for CVE-2020-37151

Vulnerability Analysis

This SQL injection vulnerability (CWE-89: Improper Neutralization of Special Elements used in an SQL Command) exists in the deluser.php endpoint of phpMyChat Plus. The application fails to properly sanitize user-supplied input in the pmc_username parameter before incorporating it into SQL queries. This lack of input validation allows attackers to inject arbitrary SQL commands that are executed by the underlying database engine.

The vulnerability supports multiple exploitation techniques, making it particularly dangerous. Boolean-based blind injection allows attackers to infer database contents through true/false responses, error-based injection leverages database error messages to extract data directly, and time-based blind injection uses deliberate delays to exfiltrate information when other methods are not viable.

Root Cause

The root cause of this vulnerability is insufficient input validation and sanitization in the deluser.php script. The pmc_username parameter is directly concatenated into SQL query strings without proper escaping or the use of parameterized queries (prepared statements). This classic SQL injection pattern allows attacker-controlled input to modify the structure and logic of database queries.

Attack Vector

The attack vector is network-based, requiring no authentication or user interaction. An attacker can craft malicious HTTP requests to the deluser.php endpoint, injecting SQL payloads through the pmc_username parameter. The vulnerability can be exploited remotely by any attacker who can reach the vulnerable phpMyChat Plus installation over the network.

The exploitation process involves sending specially crafted requests containing SQL metacharacters and commands within the username field. These payloads manipulate the underlying query to extract database schema information, enumerate tables, and ultimately dump sensitive data including user credentials and chat messages.

For detailed technical information on exploitation, refer to the Exploit-DB #48066 entry which contains a proof-of-concept demonstration.

Detection Methods for CVE-2020-37151

Indicators of Compromise

• HTTP requests to deluser.php containing SQL metacharacters such as single quotes, double dashes, UNION statements, or time-delay functions (e.g., SLEEP(), BENCHMARK())
• Database error messages in application logs indicating malformed SQL syntax
• Unusual database query patterns or execution times suggesting time-based blind SQL injection attempts
• Unexpected data access patterns in database audit logs targeting user tables

Detection Strategies

• Deploy Web Application Firewalls (WAF) with SQL injection rulesets to inspect and block malicious requests to the deluser.php endpoint
• Implement application-layer monitoring to detect anomalous parameter values containing SQL syntax in the pmc_username field
• Review web server access logs for requests to deluser.php with URL-encoded or plaintext SQL injection payloads
• Enable database query logging to identify injection attempts and unauthorized data extraction

Monitoring Recommendations

• Configure alerting for repeated requests to deluser.php from single IP addresses, which may indicate automated exploitation attempts
• Monitor for database errors related to SQL syntax in application and database logs
• Implement rate limiting on the deluser.php endpoint to slow automated attacks
• Deploy intrusion detection systems (IDS) with signatures for common SQL injection patterns

How to Mitigate CVE-2020-37151

Immediate Actions Required

• Remove or disable the deluser.php script if user deletion functionality is not required in your deployment
• Implement Web Application Firewall rules to block requests containing SQL injection patterns to the affected endpoint
• Restrict network access to the phpMyChat Plus installation to trusted IP addresses only
• Review database logs for signs of previous exploitation and assess potential data exposure

Patch Information

No official vendor patch has been identified in the available CVE data. System administrators should consult the CiprianMP Latest Updates page for any available updates or patches from the developer. For additional context, refer to the VulnCheck Advisory on SQL Injection.

Workarounds

• Modify the deluser.php source code to use parameterized queries (prepared statements) with PDO or MySQLi instead of direct string concatenation
• Implement strict input validation on the pmc_username parameter, allowing only alphanumeric characters and rejecting SQL metacharacters
• Consider migrating to an actively maintained chat application if phpMyChat Plus is no longer receiving security updates
• Deploy a reverse proxy with SQL injection filtering capabilities in front of the application

# Example .htaccess configuration to restrict access to deluser.php
<Files "deluser.php">
    Order Deny,Allow
    Deny from all
    # Allow only from trusted admin IP
    Allow from 192.168.1.100
</Files>