Remote File Inclusion
Remote File Inclusion (RFI) is a web application vulnerability that allows an attacker to include remote files, typically from a malicious server, into a vulnerable web application's execution flow. This occurs when user-supplied input is used to dynamically include files without proper validation or sanitization, enabling the execution of arbitrary code on the target server. RFI can lead to severe security breaches, such as data theft, server compromise, or malware distribution.
Developers should learn about RFI to understand and mitigate security risks in web applications, especially when handling dynamic file inclusions in languages like PHP. It is crucial for building secure software by implementing input validation, using allowlists for file sources, and disabling dangerous functions like 'include' or 'require' with remote URLs. Use cases include auditing code for vulnerabilities, conducting penetration testing, and following secure coding practices in development workflows.