cis-apache24-10-3

name	cis-apache24-10.3
description	Ensure the LimitRequestFieldsize Directive is Set to 8190 or Less (Automated)
category	cis-apache
version	2.3.0
author	cyberstrike-official
tags	["cis","apache","linux","request-limits","buffer-overflow","limit-request-fieldsize"]
cis_id	10.3
cis_benchmark	CIS Apache HTTP Server 2.4 Benchmark v2.3.0
tech_stack	["linux","apache"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

Ensure the LimitRequestFieldsize Directive is Set to 8190 or Less (Automated)

Profile Applicability

• Level 2

Description

The LimitRequestFieldSize limits the number of bytes that will be allowed in an HTTP request header. It is recommended that the LimitRequestFieldSize directive be set to the default value of 8190 or less.

Rationale

By limiting of the size of request headers is helpful so that the web server can prevent an unexpectedly long or large value from being passed to a potentially vulnerable program. Of course, the underlying dependency is that we need to set the limits high enough to not interfere with any one application on the server, while setting them low enough to be of value in protecting the applications. Since the configuration directives are available only at the server configuration level, it is not possible to tune the value for different portions of the same web server. Please read the Apache documentation carefully, as these requests may interfere with the expected functionality of some web applications.

Audit

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

Verify that the LimitRequestFieldsize directive is in the Apache configuration and has a value of 8190 or less.

Remediation

Perform the following to implement the recommended state:

Add or modify the LimitRequestFieldsize directive in the Apache configuration to have a value of 8190 or less.

LimitRequestFieldsize 8190

Default Value

LimitRequestFieldsize=8190

References

1. https://httpd.apache.org/docs/2.4/mod/core.html#limitrequestfieldsize

CIS Controls

v8:

• 4.2 Establish and Maintain a Secure Configuration Process for Network Infrastructure
  • Establish and maintain a secure configuration process for network devices. Review and update documentation annually, or when significant enterprise changes occur that could impact this Safeguard.

v7:

• 5.1 Establish Secure Configurations
  • Maintain documented, standard security configuration standards for all authorized operating systems and software.

Profile