cis-apache-5-7

name	cis-apache-5.7
description	Ensure HTTP Request Methods Are Restricted
category	cis-apache
version	3.6.0
author	cyberstrike-official
tags	["cis","apache","linux","features","content","options","http-methods"]
cis_id	5.7
cis_benchmark	CIS Apache HTTP Server 2.2 Benchmark v3.6.0
tech_stack	["linux","apache"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

Ensure HTTP Request Methods Are Restricted

Description

Use the Apache <LimitExcept> directive to restrict unnecessary HTTP request methods of the web server so it only accepts and processes the GET, HEAD, POST and OPTIONS HTTP request methods.

Rationale

The HTTP 1.1 protocol supports several request methods which are rarely used and potentially high risk. For example, methods such as PUT and DELETE are rarely used and should be disabled in keeping with the security principle of minimizing features and options. Also, since these methods are rarely used, they typically have to modify resources on the web server, they should be explicitly disallowed. For normal web server operation, you will typically need to allow only the GET, HEAD and POST request methods. This will allow for downloading web pages and submitting information to web forms. The OPTIONS request method will also be allowed as it is used to request which HTTP request methods are allowed. Unfortunately, the Apache <LimitExcept> directive does not deny the TRACE request method. The TRACE request method is disallowed in another benchmark recommendation with the TraceEnable directive.

Impact

None documented

Audit Procedure

Perform the following to determine if the recommended state is implemented:

1. Locate the Apache configuration files and included configuration files.
2. Search for all <Directory> directives other than the OS root directory.
3. Ensure that group contains a single Order directive within the <Directory> directive with a value of deny,allow.
4. Verify the <LimitExcept> directive does not include any HTTP methods other than GET, POST, and OPTIONS. (It may contain fewer methods.)

Remediation

Perform the following to implement the recommended state:

1. Locate the Apache configuration files and included configuration files.
2. Search for the directive on the document root directory, such as:

<Directory "/usr/local/apache2/htdocs">
   . . .
</Directory>