How to prevent pointer variable attacks in Nginx

Nginx is a powerful open source web server software that provides very comprehensive and flexible configuration options. However, pointer variables exist in WEB applications, and attackers can use them to obtain sensitive information or access unauthorized resources. In this article, we will learn how to protect against pointer variable attacks in Nginx.

1. Understanding pointer variable attacks

The pointer is a very basic concept in C language. It is actually a variable used to store a memory address. An attacker can change the value of a pointer variable by constructing a malicious URL in a WEB application, which may cause the server to return unauthorized resources or sensitive information.

For example, if a WEB application uses pointer variables to save user IDs, an attacker may obtain other users' data by constructing the following malicious URL:

http://example.com/ index.php?id=2001;/badcode.php

2. Methods to prevent pointer variable attacks

1. Filter the URL

Filter out Marking all pointers in URLs is the simplest way to protect against pointer variable attacks. This can be achieved using Nginx's built-in rewrite module. Add the following code in the Nginx configuration file:

if ($request_uri ~ "(.)/(.)test(/|?)(.*)") {

return 403;

}

When any URL containing "test" is matched, a 403 Forbidden error page is returned.

2. Standardize programming practices

The development team should standardize programming practices to ensure that no potential loopholes are left in the code. For the use of pointer variables, especially when dealing with sensitive data, more stringent logical judgments should be used and input data should be strictly filtered.

3. Using Nginx's security module

The Nginx security module provides some additional security features that can improve the security of WEB applications. For example, using Nginx's security module can intercept common attack vectors, such as SQL injection, cross-site scripting attacks, etc.

4. Restrict HTTP request methods

Attackers generally use the POST and GET methods in the HTTP request method to attack. To prevent attacks, the use of HTTP request methods can be restricted. Add the following code to the Nginx configuration file to limit only GET requests:

if ($request_method !~ ^(GET)$ ){

return 412;

}

The above code can limit the use of HTTP request methods other than GET, and the return status code is 412. This can improve server security, but may also affect certain WEB applications.

3. Summary

Pointer variable attack is one of the common attack vectors in WEB applications. Development teams should take basic security measures, add additional security features to WEB applications, and use the security modules provided by Nginx for security prevention. These measures can effectively prevent pointer variable attacks and improve the security of WEB applications.

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