Bug Bounty Hunting — Complete Guide (Part-108)

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The HTTP Proxy-Authorization request header is used by a client (e.g., a browser) to provide authentication credentials to a proxy server. It’s sent in response to a 407 Proxy Authentication Required status code from the proxy, which includes a Proxy-Authenticate header specifying the required authentication scheme.

How it Works:

When a proxy server requires authentication, it sends a 407 response with a Proxy-Authenticate header. The client then constructs a Proxy-Authorization header containing the necessary credentials and resubmits the request.

Syntax:

HTTP

Proxy-Authorization: <auth-scheme> <credentials>

Directives:

<auth-scheme>: A case-insensitive token indicating the authentication scheme (e.g., Basic, Digest, Negotiate, NTLM, Bearer). This must match one of the schemes offered by the proxy in the Proxy-Authenticate header.<credentials>: The credentials themselves, formatted according to the chosen <auth-scheme>.

Common Authentication Schemes and Credential Formats:

Basic: Credentials are encoded as <username>:<password>…