ASPNuke 0.80 'register.asp' SQL Injection Explained

What this paper is

This paper details a SQL injection vulnerability found in ASPNuke version 0.80. Specifically, it targets the register.asp file, allowing an attacker to inject malicious SQL code through the StateCode parameter. This injection can lead to unauthorized data modification, such as altering content in the tblPoll table.

Simple technical breakdown

The vulnerability lies in how the register.asp script handles user input for the StateCode parameter. Instead of properly sanitizing or validating this input, the script directly incorporates it into a SQL query. An attacker can craft a StateCode value that includes SQL commands. When the script executes the query, these injected commands are run by the database, potentially leading to unintended actions like updating database records.

The exploit uses a common SQL injection technique:

1. Breaking out of the intended query: The attacker injects characters like a single quote (') to terminate the original SQL string and a semicolon (;) to signal the end of the original SQL statement.
2. Injecting new commands: After the original statement is terminated, the attacker adds their own SQL commands. In this case, it's an UPDATE statement to modify the Question column in the tblPoll table.
3. Commenting out the rest: Finally, -- is used to comment out any remaining parts of the original SQL query, preventing syntax errors and ensuring only the injected commands are executed.

Complete code and payload walkthrough

The provided paper does not contain executable code in the traditional sense (like a C program or Python script). Instead, it provides a URL pattern and an example of a malicious URL that exploits the vulnerability. The "code" here refers to the crafted URL and the SQL commands embedded within it.

Let's break down the example URL:

http://[target]/[path]//module/account/register/register.asp?StateCode=0',0,0,0,0,0);update%20tblPoll%20set%20Question%20=%20'hacked'--&FirstName=namename1&LastName=namename2&Username=abcdefghijk&Password=1234567890&Confirm=1234567890&Address1=kro.mahallesi&Address2=kro.apt&City=aaaaaaaaa&ZipCode=101010101&CountryID=0&Email=mailmail@mailbidaamail.com&Action=ADD&_dummy=Register

URL Components and their purpose:

• http://[target]/[path]//module/account/register/register.asp: This is the base URL pointing to the vulnerable script.
  • [target]: Placeholder for the IP address or domain name of the victim server.
  • [path]: Placeholder for the directory where ASPNuke is installed.
  • register.asp: The specific ASP script that contains the vulnerability.
• ?StateCode=0',0,0,0,0,0);update%20tblPoll%20set%20Question%20=%20'hacked'--: This is the core of the exploit.
  • StateCode=: The parameter name that is vulnerable to SQL injection.
  • 0: This is likely the original, expected value for StateCode.
  • ': This single quote terminates the string literal that StateCode was supposed to be part of in the original SQL query.
  • ,0,0,0,0,0): These are likely other parameters or values that were part of the original SQL query, now being "closed off" by the injected quote and parentheses. The exact number and values depend on the original query structure.
  • ;: This semicolon separates the original SQL statement from the new, injected SQL statement.
  • update%20tblPoll%20set%20Question%20=%20'hacked': This is the injected SQL command.
    • update: SQL command to modify existing records.
    • tblPoll: The target table to be updated.
    • set Question = 'hacked': Sets the Question column in the tblPoll table to the value 'hacked'.
    • %20: URL-encoded space character.
  • --: This is a SQL comment. It tells the database to ignore any characters that follow it in the current SQL statement. This is crucial to prevent syntax errors from the remaining parts of the original query.
• &FirstName=namename1&LastName=namename2&Username=abcdefghijk&Password=1234567890&Confirm=1234567890&Address1=kro.mahallesi&Address2=kro.apt&City=aaaaaaaaa&ZipCode=101010101&CountryID=0&Email=mailmail@mailbidaamail.com&Action=ADD&_dummy=Register: These are the legitimate form parameters required by register.asp to complete the registration process. They are included to make the request look like a normal registration attempt, even though the StateCode parameter is being abused.

Mapping list:

• StateCode=[SQL] -> Practical Purpose: The entry point for injecting malicious SQL commands.
• 0',0,0,0,0,0) -> Practical Purpose: To correctly terminate the original SQL query string and any associated parameters, preventing syntax errors before the injected command.
• ; -> Practical Purpose: To separate the original SQL statement from the injected SQL statement.
• update%20tblPoll%20set%20Question%20=%20'hacked' -> Practical Purpose: The actual malicious SQL command to alter data in the tblPoll table.
• -- -> Practical Purpose: To comment out the remainder of the original SQL query, ensuring only the injected command is executed and avoiding syntax errors.
• &FirstName=...&Email=...&Action=ADD&_dummy=Register -> Practical Purpose: To provide valid data for the rest of the registration form, making the exploit request appear legitimate and allowing the malicious SQL to be executed as part of a seemingly normal operation.

Shellcode/Payload Segment Explanation:

There is no traditional shellcode or multi-stage payload in this exploit. The "payload" is the SQL injection itself, which directly manipulates the database. The effect is to change data within the tblPoll table.

Practical details for offensive operations teams

• Required Access Level: Network access to the target web server is sufficient. No elevated privileges on the server itself are initially required, beyond the ability to send HTTP requests.
• Lab Preconditions:
  • A vulnerable ASPNuke 0.80 installation.
  • A web server configured to run ASP (e.g., IIS on Windows).
  • A database backend (likely MS SQL Server, common for ASP applications of that era) accessible by the web server.
  • The tblPoll table must exist and be accessible for modification.
  • The register.asp script must be configured to accept and process the StateCode parameter in a way that leads to SQL injection.
• Tooling Assumptions:
  • A web browser for manual testing or reconnaissance.
  • An HTTP proxy (like Burp Suite or OWASP ZAP) to intercept and modify requests.
  • A command-line tool like curl or wget for scripting/automation.
  • SQL injection tools (e.g., SQLMap, though it might require specific configuration for older ASP/SQL Server combinations) could be used for more advanced discovery and exploitation, but manual crafting is demonstrated here.
• Execution Pitfalls:
  • Incorrect Path/Target: The exploit will fail if the [target] or [path] are incorrect, or if the register.asp file is not located at the specified relative path (/module/account/register/).
  • WAF/IDS Evasion: Modern Web Application Firewalls (WAFs) or Intrusion Detection Systems (IDS) would likely flag the injected SQL syntax (', ;, --, UPDATE) and URL-encoded characters (%20). Evasion techniques might be necessary.
  • Database Schema Differences: If the tblPoll table or its Question column does not exist, or if the original SQL query structure is different from what the exploit assumes, the injection will fail. The exploit relies on specific table and column names.
  • Username Conflict: The note "Change UserName because ; failed:already username dont write" indicates that the Username field must be unique. If the chosen Username already exists, the registration process might fail before the SQL injection can be fully leveraged, or the database might reject the update due to constraints.
  • Parameter Order/Count: The injected 0',0,0,0,0,0) assumes a specific number of parameters or values expected by the original SQL query. If the original query structure changes, this part of the injection might need adjustment.
  • Database Permissions: While the injection can modify data, the web application's database user must have UPDATE permissions on the tblPoll table.
• Tradecraft Considerations:
  • Reconnaissance: Thoroughly map the target application, identify the register.asp endpoint, and understand its parameters. Look for other input fields that might be vulnerable.
  • Payload Customization: The update statement is a demonstration. For actual operations, an attacker might aim to extract data (using techniques like UNION-based SQL injection, if applicable and not blocked by the initial injection), or to drop tables, create new users, or execute more complex commands depending on the database and its configuration.
  • Stealth: The exploit's effectiveness is reduced if it's part of a noisy, brute-force attempt. Careful, targeted requests are more likely to go unnoticed.
  • Post-Exploitation: If successful, the attacker has demonstrated the ability to modify data. This could be a precursor to more advanced attacks, such as gaining further access or establishing persistence.

Where this was used and when

• Context: This vulnerability was discovered and published in 2006. ASPNuke was a popular open-source Content Management System (CMS) for ASP-based websites at the time.
• Usage: Vulnerabilities like this were commonly exploited against websites running older, unpatched versions of web applications. Attackers would scan for vulnerable sites and use automated tools or manual techniques to inject SQL code, often to deface websites, steal user credentials, or gain unauthorized access.
• Approximate Years/Dates: The exploit was published on November 19, 2006. Exploitation would have occurred around this time and in subsequent years as long as vulnerable versions of ASPNuke remained in use.

Defensive lessons for modern teams

• Input Validation and Sanitization: This is the cornerstone of preventing SQL injection. All user-supplied input, especially data that will be used in database queries, must be rigorously validated and sanitized.
  • Parameterized Queries/Prepared Statements: This is the most effective defense. Instead of building SQL strings with user input, use placeholders that the database driver fills with the actual data, treating it as literal values, not executable code.
  • Whitelisting: Only allow known-good characters or patterns for input fields.
  • Blacklisting (less effective): Avoid relying solely on blocking known-bad characters, as attackers can often find ways around them.
• Principle of Least Privilege: The database user account used by the web application should have only the minimum necessary permissions. If the web application's user cannot UPDATE tables it doesn't need to, an injection targeting UPDATE statements will fail.
• Web Application Firewalls (WAFs): While not a complete solution, WAFs can provide a layer of defense by detecting and blocking common attack patterns, including SQL injection attempts. However, they must be kept up-to-date and configured correctly.
• Regular Patching and Updates: Keep all web applications, CMS platforms, and their underlying frameworks updated to the latest secure versions. Vulnerabilities like this are often fixed in later releases.
• Secure Coding Practices: Educate developers on secure coding principles, including the dangers of SQL injection and how to prevent it. Code reviews should explicitly check for these vulnerabilities.
• Database Auditing and Monitoring: Monitor database logs for suspicious activity, such as unusual query patterns, unexpected data modifications, or access attempts from unexpected sources.

ASCII visual (if applicable)

This exploit is a direct manipulation of data flow within a web application and its database. An ASCII diagram can illustrate the general concept:

+-----------------+      +-----------------+      +-----------------+
| Attacker's      |----->| Web Server      |----->| Database Server |
| Machine         |      | (ASPNuke App)   |      | (SQL Server)    |
+-----------------+      +-------+---------+      +-----------------+
                         ^       |
                         |       | (Malicious SQL Query)
                         |       v
                         | +-----------------+
                         | | register.asp    |
                         | | (Vulnerable)    |
                         | +-----------------+
                         |
                         | (Legitimate Form Data)
                         +-----------------+

Explanation:

1. The attacker sends an HTTP request to the web server.
2. The register.asp script on the web server receives the request.
3. Due to the vulnerability, the StateCode parameter's content, which includes injected SQL, is directly passed to the database.
4. The database server executes the malformed SQL query, leading to unauthorized data modification (e.g., updating tblPoll).

Source references

• Paper ID: 2813
• Paper Title: ASPNuke 0.80 - 'register.asp' SQL Injection
• Author: ajann
• Published: 2006-11-19
• Keywords: ASP, webapps
• Paper URL: https://www.exploit-db.com/papers/2813
• Raw URL: https://www.exploit-db.com/raw/2813

Original Exploit-DB Content (Verbatim)

*******************************************************************************
# Title  :  ASPNuke <= 0.80 (register.asp) Remote SQL Injection Vulnerability
# Author :  ajann
# S.Page :  http://www.aspnuke.com
# D.Page :  http://sourceforge.net/project/showfiles.php?group_id=92470

*******************************************************************************

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
ASP Nuke
Kenneth W. Richards
Orvado Technologies
-Introduction-

ASP Nuke is an open-source software application for running a
community-based web site on a web server.
By open-source, we mean the code is freely available for others to read,
modify and use in accordance
with the software license.
ASP Nuke is an extensible framework that allows you to upgrade and add
applications to the website quickly
and easily. It uses a modular architecture allowing others to rapidly
develop new modules and site operators
to re-organize the layout and navigation for their site.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Vulnerability::
_________________

###http://[target]/[path]//module/account/register/register.asp?StateCode=[SQL]&..&..&..&..&..&..&..&..&....

Example = Poll Update

///module/account/register/register.asp?StateCode=0',0,0,0,0,0);update%20tblPoll%20set%20Question%20=%20'hacked'--&FirstName=namename1&LastName=namename2&Username=abcdefghijk&Password=1234567890&Confirm=1234567890&Address1=kro.mahallesi&Address2=kro.apt&City=aaaaaaaaa&ZipCode=101010101&CountryID=0&Email=mailmail@mailbidaamail.com&Action=ADD&_dummy=Register

Note: Change UserName because ; failed:already username dont write.

Some tables,columns
___________________

[tblMember]    |  [FaqQuestion]
MemberID       |  QuestionID
Username       |  DocumentID
Password       |  Question
Firstname      |  Answer
Middlename     |  Active
EmailAddress   |  OrderNo
..             |  ..


"""""""""""""""""""""
# ajann,Turkey
# ...

# Im not Hacker!

# milw0rm.com [2006-11-19]