2.6 KiB
| obj | wiki | rev |
|---|---|---|
| concept | https://en.wikipedia.org/wiki/File_inclusion_vulnerability | 2024-05-02 |
File Inclusion Vulnerabilities
File Inclusion Vulnerabilities are a type of security exploit that occurs when an application allows an attacker to include a file, usually a malicious one, on a server through a script. This vulnerability is commonly found in web applications and can have serious consequences if exploited.
Types of File Inclusion Vulnerabilities
There are two main types of file inclusion vulnerabilities:
- Remote File Inclusion (RFI): In RFI, an attacker can include remote files hosted on a different server. This allows the attacker to execute malicious code or retrieve sensitive information from the server.
- Local File Inclusion (LFI): In LFI, an attacker can include files that are already present on the server. These files could be system files, configuration files, or any other file accessible to the web server process.
Exploitation
File inclusion vulnerabilities are typically exploited by manipulating input parameters in a web application that are used to specify the file to be included. Attackers can modify these parameters to include arbitrary files, leading to unauthorized access or execution of malicious code.
Example of Exploitation
Consider a PHP web application that includes files based on a page parameter in the URL:
<?php
$page = $_GET['page'];
include($page . '.php');
?>
An attacker can exploit this vulnerability by providing a malicious page parameter:
http://example.com/index.php?page=malicious_script
If the application does not properly sanitize input, the attacker's script (malicious_script.php) will be included and executed by the server.
Mitigation
To prevent file inclusion vulnerabilities, developers should follow best practices for secure coding:
- Input Validation: Validate and sanitize all user-supplied input to ensure that it conforms to expected formats and does not contain malicious content.
- Whitelisting: Maintain a whitelist of allowed files or directories that can be included. Only include files that are explicitly allowed, and reject all others.
- Use Absolute Paths: Instead of including files based on user-supplied input, use absolute paths or predefined constants to specify file locations.
- Limit File Permissions: Restrict the permissions of files and directories to minimize the impact of a successful exploitation.
- Security Headers: Implement security headers, such as Content Security Policy (CSP), to prevent inclusion of external resources.