Cis Apache24 5.17
DevOps & Securitycis-apache24-5.17Cis Apache24 5.17 is an Agent Skill for devops & security published in the CyberStrikeus/CyberStrike repository on GitHub: a SKILL.md instruction file an AI agent can load to do this task.
Ensure HTTP Header Referrer-Policy is set appropriately
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Ensure HTTP Header Referrer-Policy is set appropriately (Manual)
Profile Applicability
Level 2
Description
The server now allows for controlling the amount of "referrer" information being sent with requests. Limiting information to only what is needed is security best practice.
Rationale
HTTP/S traffic is vulnerabe to attack - limiting what is sent in a request to only what is needed will limit the threat vector.
Impact
You must only limit the header information to what is needed to support the request. Limiting it to much may disrupt the ability to get a proper/expected response.
Audit Procedure
Perform the following steps to determine if the recommended state is implemented:
- Ensure a Header directive for Referrer-Policy is present in the Apache configuration and has the condition Header Set 'Referrer-Policy' shown below:
# grep -I Referrer-Policy $APACHE_PREFIX/conf/httpd.confHeader set Referrer-Policy "<Directive>"
If header Referrer-Policy configuration is present and has as a compliant value, then the server is compliant.
Remediation
Perform the following to implement the recommended state:
Add or modify the Header directive for the Referrer-Policy header in the Apache configuration to have the appropriate condition as shown below.
Header set Referrer-Policy "<Directive>"
Default Value
Referrer-Policy Policy is not set by Default
References
- https://httpd.apache.org/docs/2.4/mod/mod_headers.html#header
- https://owasp.org/www-project-cheat-sheets/cheatsheets/Content_Security_Policy_Cheat_Sheet
- https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy
- https://en.wikipedia.org/wiki/Clickjacking
CIS Controls
v8:
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9.4 Restrict Unnecessary or Unauthorized Browser and Email Client Extensions
- Restrict, either through uninstalling or disabling, any unauthorized or unnecessary browser or email client plugins, extensions, and add-on applications.
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13.10 Perform Application Layer Filtering
- Perform application layer filtering. Example implementations include a filtering proxy, application layer firewall, or gateway.
v7:
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9.4 Apply Host-based Firewalls or Port Filtering
- Apply host-based firewalls or port filtering tools on end systems, with a default-deny rule that drops all traffic except those services and ports that are explicitly allowed.
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18.2 Ensure Explicit Error Checking is Performed for All In-house Developed Software
- For in-house developed software, ensure that explicit error checking is performed and documented for all input, including for size, data type, and acceptable ranges or formats.