Exploiting Scripts Feed Business Directory Login via SQL Injection

What this paper is

This paper details a SQL injection vulnerability found in the login functionality of the "Scripts Feed Business Directory" web application. The vulnerability allows an attacker to manipulate the SQL queries executed by the application by injecting malicious SQL code into the username or password fields during the login process.

Simple technical breakdown

The core of the vulnerability lies in how the web application handles user input for the username and password when a user attempts to log in. Instead of properly sanitizing or validating this input, the application directly incorporates it into a SQL query. By crafting specific input strings that include SQL commands, an attacker can alter the query's logic, bypass authentication, or extract sensitive data.

Complete code and payload walkthrough

The provided exploit description is very brief and focuses on the attack vector rather than providing full exploit code or shellcode.

Exploit Description:

• Vulnerability Location: login.php
• Vulnerable POST Variables: us (username) and ps (password)
• Attack Parameters:
  • us=user (a placeholder username, could be anything)
  • ps=${SQLINJECTIONHERE} (this is where the malicious SQL is injected)
  • s1=LOGIN (a likely submit button value to trigger the login process)

Explanation of the Attack Vector:

The paper implies that the login.php script constructs a SQL query using the provided us and ps POST variables. A typical login query might look something like this (hypothetical, as the paper doesn't show the backend code):

SELECT * FROM users WHERE username = '$_POST[us]' AND password = '$_POST[ps]'

When an attacker injects SQL into the ps variable, they can alter this query. For example, if the attacker sets ps to:

' OR '1'='1

The resulting query would become:

SELECT * FROM users WHERE username = 'user' AND password = '' OR '1'='1'

The ' OR '1'='1' part is a common SQL injection technique. The '1'='1' condition is always true. When combined with an OR operator, it makes the entire WHERE clause evaluate to true, regardless of the actual username and password. This would likely allow the attacker to log in as the first user in the database, or bypass authentication entirely.

No explicit code or shellcode is provided in the paper for direct walkthrough. The paper only describes the vulnerability and the parameters used for the attack.

Code Fragment/Block -> Practical Purpose Mapping:

• login.php -> The target script handling login requests.
• us=user -> The username parameter, likely used in the WHERE clause of a SQL query.
• ps=${SQLINJECTIONHERE} -> The password parameter, the injection point for malicious SQL.
• s1=LOGIN -> A parameter likely used to identify the login submission action.
• ' OR '1'='1 (example injection) -> A payload fragment that manipulates the SQL WHERE clause to always be true, bypassing authentication.

Practical details for offensive operations teams

• Required Access Level: Network access to the target web application. No prior authenticated access is strictly required for this specific vulnerability, as it targets the login page itself.
• Lab Preconditions:
  • A vulnerable instance of "Scripts Feed Business Directory" installed and accessible.
  • A web server environment (e.g., Apache, Nginx) running PHP and a database (e.g., MySQL) configured for the application.
  • Tools to send HTTP POST requests (e.g., Burp Suite, curl, custom scripts).
• Tooling Assumptions:
  • Web Proxy/Interception Tool: Essential for capturing and modifying HTTP requests. Burp Suite is a common choice.
  • SQL Injection Tools (Optional but Recommended): Tools like sqlmap can automate the discovery and exploitation of SQL injection vulnerabilities, including identifying the exact injection payload and database schema.
  • Custom Scripting: Python with libraries like requests can be used to craft and send specific POST requests.
• Execution Pitfalls:
  • WAF/IDS Evasion: Modern Web Application Firewalls (WAFs) and Intrusion Detection Systems (IDS) may detect common SQL injection patterns. Payloads might need obfuscation or alternative injection techniques.
  • Incorrect Parameter Identification: If the login.php script has changed or uses different parameter names, the exploit might fail. Thorough reconnaissance is key.
  • Database Specific Syntax: The exact SQL injection payload might need to be tailored to the specific database system (e.g., MySQL, PostgreSQL, SQL Server) used by the application. The paper doesn't specify the database.
  • Error Handling: The application's error handling can reveal information. Verbose error messages might expose the injected SQL query or database structure, aiding further exploitation. Conversely, silent failures might obscure the attack.
  • Rate Limiting/Account Lockout: Repeated failed login attempts might trigger account lockouts or rate limiting, hindering brute-force or systematic testing.
• Telemetry:
  • Web Server Logs: Look for unusual POST requests to login.php with crafted us and ps parameters.
  • Database Logs: Monitor for unexpected or malformed SQL queries originating from the web server.
  • Application Logs: If the application logs authentication attempts or errors, these might show signs of the injection attempt.
  • Network Traffic: Unusual patterns in HTTP POST requests, especially those containing SQL keywords or special characters (', ;, --, OR, AND).

Where this was used and when

• Context: This vulnerability was relevant to any organization using the "Scripts Feed Business Directory" web application.
• Approximate Year: The paper was published in February 2010. Therefore, this vulnerability was actively exploitable around 2010 and potentially for some time afterward until the application was patched or updated. The paper states "Version: [ ALL ]", suggesting it affected all versions available at that time.

Defensive lessons for modern teams

• Input Validation and Sanitization: This is the most critical defense. All user-supplied input, especially data that will be used in database queries, must be rigorously validated and sanitized.
  • Parameterized Queries/Prepared Statements: Use these exclusively for database interactions. They separate SQL code from data, preventing injection.
  • Whitelisting: Only allow known-good characters and formats for input.
  • Blacklisting (less effective but still useful): Block known-malicious characters and keywords, but be aware that attackers can often bypass these.
• Least Privilege Principle: The database user account used by the web application should have only the minimum necessary permissions. It should not be able to drop tables, create users, or access sensitive system tables.
• Web Application Firewalls (WAFs): While not a sole solution, WAFs can provide an additional layer of defense by detecting and blocking common attack patterns, including SQL injection attempts. Keep WAF rules updated.
• Regular Security Audits and Patching: Regularly scan web applications for vulnerabilities and apply security patches promptly.
• Secure Coding Practices: Train developers on secure coding principles, including the dangers of SQL injection and how to prevent it.
• Error Handling: Configure web applications to display generic error messages to users. Detailed error messages can leak sensitive information to attackers. Log detailed errors server-side for debugging.

ASCII visual (if applicable)

+-----------------+      +------------------------+      +-----------------+
| Attacker's Input| ---> | login.php (Vulnerable) | ---> | Database Server |
| (e.g., ' OR '1'='1')|      |                        |      |                 |
+-----------------+      |                        |      |                 |
                         |  Constructs SQL Query  |      |                 |
                         |  (without sanitization)|      |                 |
                         +----------+-------------+      +-----------------+
                                    |
                                    | Malicious SQL Query
                                    v
                         +-----------------+
                         |  Database Query |
                         | (e.g., SELECT *) |
                         | FROM users WHERE|
                         | username = '...'|
                         | AND password =  |
                         | '' OR '1'='1'   |
                         +-----------------+

Source references

• Paper ID: 11592
• Paper Title: Scripts Feed Business Directory - SQL Injection
• Author: Crux
• Published: 2010-02-27
• Paper URL: https://www.exploit-db.com/papers/11592
• Raw URL: https://www.exploit-db.com/raw/11592

Original Exploit-DB Content (Verbatim)

==============================================================================
    [~] Scripts Feed Business Directory SQL Injection Vulnerability
==============================================================================
    [+] My home          [ http://hack-tech.com ]
    [+] Date Submitted:  [ February 27 2010 ]
    [+] Founder:         [ Crux ]
    [+] Vendor:          [ Scriptsfeed ]
    [+] Version:         [ ALL ]
    [+] Download:        [ http://www.scriptsfeed.com/business-directory.html ]


[ EXPLOIT ]
- This vulnerability affects login.php
-The POST variables 'us' and 'ps' are vulnerable.

[ ATTACK DETAILS ]
us=user&ps=${SQLINJECTIONHERE}&s1=LOGIN

==============================================================================