Local File Inclusion

Local File Inclusion (LFI) is a web application Vulnerability that allows an attacker to include files on the server through input provided to the application. LFI typically occurs when user input is not properly validated, enabling attackers to access and execute files from the local file system, potentially exposing sensitive information or compromising the server.

LFI vulnerabilities arise when an application dynamically loads files based on user input without adequate input sanitisation. This can lead to attackers including unintended files, such as configuration files or sensitive data stored on the server. LFI is often Exploited to gain information about the server environment, read sensitive files, or execute local scripts.

The purpose of Exploiting LFI is to gain unauthorised access to files and potentially execute code on the server. Attackers may leverage LFI to gather sensitive data, such as credentials, configuration settings, or to escalate their privileges within the target environment. It poses a significant risk, especially when combined with other vulnerabilities.

LFI attacks are conducted by manipulating file path parameters passed to the application, allowing attackers to include files from the local file system. For example, providing '../' sequences (Directory Traversal) as input may enable access to files outside the intended directory. Preventing LFI requires input validation, sanitising user inputs, and using secure coding practices that limit file inclusion to expected paths.

Examples of LFI include accessing '/etc/passwd' on a Unix-based system by manipulating input parameters in a web application, or including sensitive log files that may contain useful data for further Exploitation. Attackers may also use LFI in combination with log file poisoning to execute injected code.

LFI vulnerabilities can lead to information disclosure, remote code execution, and full system compromise. To mitigate the risk, developers should validate and sanitise user inputs, restrict file inclusion paths, and adhere to the principle of Least Privilege. Regular security testing and code reviews are essential to detect and fix LFI vulnerabilities.