Deprecated Feature-Policy Header Detection Scanner

The Deprecated Feature-Policy Header is utilized in web applications to control features that a website can use. Developers and organizations often employ these headers to enhance site security and improve user privacy. Although still recognized by some browsers, it is recommended to migrate to the newer Permissions-Policy header to ensure web applications remain secure and future-proof. This scanner is used to identify digital assets still utilizing the deprecated Feature-Policy header, aiding in the transition to the updated policy structure. The implementation of feature-control headers like this is essential in managing web application capabilities responsibly.

The detection involves identifying the presence of the Deprecated Feature-Policy HTTP response header. This header has been phased out in favor of the Permissions-Policy header, which offers expanded capabilities and improved syntax. While backward compatibility allows its current usage, migrating to the updated header is advisable. Scanners capable of detecting such legacy configurations are crucial for developers seeking to update and secure their applications according to modern standards.

The scanner searches for HTTP headers returning the 'Feature-Policy' keyword in responses. This header's identification suggests a need for updating to the Permissions-Policy protocol. Typically, an inspection of server responses is performed, followed by extracting relevant header values. This detailed examination helps pinpoint specific assets requiring attention, aiding in the mitigation of potential security risks associated with legacy headers.

Exploitation of the deprecated Feature-Policy header may lead to unintended security vulnerabilities in web applications. Persistent use of outdated headers might provide attackers with opportunities to exploit modern web clients that follow stricter security protocols. Attacks can include unauthorized feature access or data leaks if legacy headers enable them inadvertently. Ensuring the transition to updated headers like Permissions-Policy is vital to maintaining robust web application security.

REFERENCES

• https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Feature-Policy
• https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Permissions-Policy
• https://www.w3.org/TR/permissions-policy-1/
• https://github.com/w3c/webappsec-permissions-policy/blob/main/permissions-policy-explainer.md