CVE-2023-6567: Thimpress LearnPress SQL Injection Flaw

CVE-2023-6567 Overview

The LearnPress plugin for WordPress is vulnerable to time-based SQL Injection via the order_by parameter in all versions up to, and including, 4.2.5.7. This vulnerability exists due to insufficient escaping on the user-supplied parameter and lack of sufficient preparation on the existing SQL query. The flaw makes it possible for unauthenticated attackers to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database.

Critical Impact

Unauthenticated attackers can exploit this SQL Injection vulnerability to extract sensitive data from the WordPress database, potentially compromising user credentials, personal information, and site configuration data.

Affected Products

• ThimPress LearnPress plugin for WordPress versions up to and including 4.2.5.7
• WordPress sites using vulnerable LearnPress plugin installations
• E-learning platforms built on WordPress with LearnPress integration

Discovery Timeline

• 2024-01-11 - CVE CVE-2023-6567 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2023-6567

Vulnerability Analysis

This SQL Injection vulnerability in the LearnPress WordPress plugin represents a significant security risk due to its unauthenticated nature. The vulnerability exists within the plugin's query handling mechanism where the order_by parameter is directly incorporated into SQL statements without proper sanitization or parameterized query implementation.

The time-based nature of this SQL injection means attackers can extract database contents by measuring response time differences when injecting conditional SQL statements. This technique allows data exfiltration even when direct query output is not returned to the attacker, making it a particularly stealthy attack vector.

LearnPress is a widely-used Learning Management System (LMS) plugin for WordPress, which means successful exploitation could expose sensitive student data, course information, payment details, and administrator credentials stored in the WordPress database.

Root Cause

The root cause of this vulnerability is the insufficient escaping of user-supplied input in the order_by parameter combined with inadequate use of prepared statements in the SQL query construction. WordPress provides built-in functions like $wpdb->prepare() for parameterized queries, but this mechanism was not properly implemented for the vulnerable parameter, allowing SQL metacharacters to break out of the intended query context.

Attack Vector

The attack vector is network-based and requires no authentication or user interaction. An attacker can craft malicious HTTP requests targeting endpoints that process the order_by parameter. By injecting time-based SQL payloads, attackers can systematically extract database contents character by character through observed response time delays.

The vulnerability is exploited by sending specially crafted requests containing SQL injection payloads within the order_by parameter. Since the attack is time-based, attackers use conditional statements with delay functions (such as SLEEP() in MySQL) to infer whether conditions are true or false based on response timing.

For technical details on the vulnerability and its remediation, see the WordPress Plugin Changeset and the Wordfence Vulnerability Report.

Detection Methods for CVE-2023-6567

Indicators of Compromise

• Unusual HTTP requests containing SQL syntax in URL parameters, particularly targeting LearnPress endpoints with suspicious order_by values
• Abnormally long response times for requests to LearnPress-related pages, indicating potential time-based SQL injection attempts
• Database query logs showing unexpected SLEEP(), BENCHMARK(), or WAITFOR DELAY functions
• Web server logs containing encoded SQL injection payloads in GET or POST parameters

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block SQL injection patterns in the order_by parameter
• Implement database activity monitoring to alert on queries containing time-delay functions from web application contexts
• Review web server access logs for patterns of repeated requests with incremental timing variations
• Monitor for anomalous database query execution times that may indicate blind SQL injection enumeration

Monitoring Recommendations

• Enable detailed logging for WordPress and the LearnPress plugin to capture all parameter values in requests
• Configure intrusion detection systems (IDS) to alert on SQL injection signature patterns
• Set up response time anomaly detection for LearnPress-related endpoints
• Implement SentinelOne's WordPress protection capabilities for real-time threat detection

How to Mitigate CVE-2023-6567

Immediate Actions Required

• Update the LearnPress plugin immediately to a version newer than 4.2.5.7 that contains the security fix
• Review database access logs for signs of exploitation attempts or successful data extraction
• Consider temporarily disabling the LearnPress plugin if immediate patching is not possible
• Implement Web Application Firewall rules to block SQL injection attempts targeting the order_by parameter

Patch Information

ThimPress has released a patched version of LearnPress that addresses this SQL Injection vulnerability. The fix can be reviewed in the WordPress Plugin Changeset. Site administrators should update to the latest version of LearnPress through the WordPress admin dashboard or by downloading the updated plugin directly from the WordPress plugin repository.

Workarounds

• Deploy a Web Application Firewall (WAF) with SQL injection protection rules to filter malicious requests before they reach the application
• Restrict database user permissions for the WordPress installation to limit the potential impact of SQL injection attacks
• Implement IP-based access controls to limit access to sensitive LearnPress functionality if full remediation cannot be immediately applied
• Consider using a security plugin that provides virtual patching capabilities for known WordPress vulnerabilities

# Configuration example - WAF rule for ModSecurity
# Add to your ModSecurity configuration to help mitigate SQL injection attempts
SecRule ARGS:order_by "@detectSQLi" \
    "id:1001,\
    phase:2,\
    deny,\
    status:403,\
    log,\
    msg:'SQL Injection attempt detected in order_by parameter',\
    tag:'application-multi',\
    tag:'language-sql',\
    tag:'attack-sqli'"