Remote File Inclusion

Description

Remote File Inclusion (RFI) is a vulnerability that allows attackers to include remote files, exploiting dynamic file inclusion mechanisms in the target application. This occurs due to the use of user-supplied input without proper validation. Attackers can execute arbitrary code on the server, leading to Server-Side Request Forgery (SSRF) issues.

Recommendation

To mitigate RFI vulnerabilities, avoid passing user-submitted input to filesystem/framework APIs. If unavoidable, maintain an allow list of files that may be included, using an identifier to access selected files. Reject any request with an invalid identifier to eliminate attack surface.

References

• OWASP: Testing for Remote File Inclusion
• Wikipedia: File inclusion vulnerability
• CWE-20
• CWE-918
• CWE-98
• CAPEC-193
• OWASP 2021-A10
• OWASP 2021-A3