CVE-2025-13673 — Tutor LMS SQL Injection Lab

Unauthenticated SQL Injection in Tutor LMS WordPress plugin (<= 3.9.6) via the coupon_code parameter.

Quick Start

# 1. Clone and start the lab
git clone https://github.com/dinosn/CVE-2025-13673.git
cd CVE-2025-13673
./setup.sh            # Deploys WordPress + Tutor LMS 3.9.3

# 2. Run the exploit
pip install requests   # only dependency

# Unauthenticated (time-based blind — no credentials needed)
python3 exploit.py http://localhost:8080

# Authenticated (UNION-based — instant extraction)
python3 exploit.py http://localhost:8080 -u testuser -p test123 --all

Vulnerability Details

Field	Value
CVE	CVE-2025-13673
Affected	Tutor LMS <= 3.9.6
Fixed	3.9.7
Type	SQL Injection (CWE-89)
CVSS	7.5 / 9.3
Auth	None (blind) / Subscriber (UNION)

Root Cause

QueryHelper::prepare_where_clause() builds SQL WHERE clauses with raw string concatenation:

// helpers/QueryHelper.php — VULNERABLE
$value = is_numeric( $value ) ? $value : "'" . $value . "'";

No escaping. A single quote breaks out of the literal and allows arbitrary SQL.

Attack Vectors

Unauthenticated: POST / with tutor_action=tutor_pay_now. The WordPress init hook dispatches this for all visitors. The _tutor_nonce is embedded in every frontend page and valid for anonymous sessions. Data extraction via SLEEP().

Subscriber+: POST /wp-admin/admin-ajax.php with action=tutor_apply_coupon. Returns JSON with injected UNION SELECT data — two columns reflected in the response for instant extraction.

Patch (3.9.7)

- $val = is_numeric( $val ) ? $val : "'" . $val . "'";
+ // Value now passed through $wpdb->prepare('%s', $value)

Exploit Usage

usage: exploit.py [-h] [-u USERNAME] [-p PASSWORD] [--course-id COURSE_ID]
                  [--dump-users] [--db-info] [--options] [--all]
                  [--delay DELAY]
                  url

Modes:
  Default (no -u/-p):  Unauthenticated time-based blind SQLi
  With -u/-p:          Authenticated UNION-based (fast)

Examples:
  exploit.py http://target                            # unauth blind
  exploit.py http://target -u student -p pass --all   # auth UNION

Testing Different Versions

# Test version 3.9.5 (has esc_sql partial mitigation)
./setup.sh 3.9.5

# Test version 3.9.7 (should be fixed)
./setup.sh 3.9.7

Files

File	Description
exploit.py	Dual-mode PoC: unauth blind + auth UNION
setup.sh	One-command lab deployment
docker-compose.yml	WordPress 6.7 + MySQL 8.0

References

• Wordfence Advisory
• Patchstack Advisory

Disclaimer

For authorized security testing and educational purposes only.