# HTTP Headers ## HTTP Header Issues ### Headi Headi is an automated HTTP header injection tool that will connect to a web server using various headers and monitor the responses for any potential weaknesses. * The following command will check for several header related issues on a URL. `headi -u URL` ## CRLF Vulnerabilities CRLF injection occurs when it is possible to insert CR and LF characters into a web application using user-supplied input. This may force the server, application, or user into interpreting the CRLF as the end of a response and the beginning of another which may lead to HTTP response splitting. ### CRLFuzz CRLFuzz is a tool to scan for CRLF vulnerabilities. * The following command will check for CRLF issues on a URL. `./crlfuzz -u `