Local File Inclusion

Description

The File Inclusion vulnerability allows an attacker to include a file, usually exploiting a “dynamic file inclusion” mechanisms implemented in the target application. The vulnerability occurs due to the use of user-supplied input without proper validation. ^OWASP

In a Local File Inclusion the content of the local file is reflected in the response. The application might execute the content of the file if it contains code.

Recommendation

The most effective solution to eliminate file inclusion vulnerabilities is to avoid passing user-submitted input to any filesystem/framework API. If this is not possible the application can maintain an allow list of files, that may be included by the page, and then use an identifier (for example the index number) to access to the selected file. Any request containing an invalid identifier has to be rejected, in this way there is no attack surface for malicious users to manipulate the path. ^OWASP

References

• OWASP: Testing for Local File Inclusion
• Wikipedia: File inclusion vulnerability
• CWE-20
• OWASP 2021-A3
• CWE-22
• OWASP 2017-A5
• OWASP 2021-A1