# Cis Tomcat101 10.6

> Enable strict servlet Compliance (Manual)

- Skill: `cyberstrikeus/cis-tomcat101-10-6` (Agent Skill)
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- Category: Coding & Dev Tools
- Author: cyberstrikeus (https://skillmd.com/u/cyberstrikeus)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/cyberstrikeus/cis-tomcat101-10-6

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# 10.6 Enable strict servlet Compliance (Manual)

## Description

The `STRICT_SERVLET_COMPLIANCE` influences Tomcat's behavior in several subtle ways. See the References below for the complete list. It is recommended that `STRICT_SERVLET_COMPLIANCE` be set to `true`.

## Rationale

When `STRICT_SERVLET_COMPLIANCE` is set to `true`, Tomcat will always send an HTTP Content-type header when responding to requests. This is significant as the behavior of web browsers is inconsistent in the absence of the Content-type header. Some browsers will attempt to determine the appropriate content-type by sniffing

## Impact

Changing this to `true` will change a number of other default values which is likely to break the majority of systems as some browsers are unable to correctly handle the cookie headers that result from a strict adherence to the specifications. Please refer to the referenced documentation for a complete list of changed values. Defaults, regardless of whether or not they have been changed by setting `org.apache.catalina.STRICT_SERVLET_COMPLIANCE` can always be overridden by explicitly setting the appropriate system property or element attribute.

## Audit Procedure

Ensure the `-Dorg.apache.catalina.STRICT_SERVLET_COMPLIANCE=true` parameter is added to the startup script which by default is located at `$CATALINA_HOME/bin/catalina.sh`.

## Remediation

Start Tomcat with strict compliance enabled, add `-Dorg.apache.catalina.STRICT_SERVLET_COMPLIANCE=true` to your startup script.

## Default Value

The default value is `false`.

## References

1. http://tomcat.apache.org/tomcat-9.0-doc/config/systemprops.html

## CIS Controls

| Controls Version | Control                                                                                                                                                                      | IG 1 | IG 2 | IG 3 |
| ---------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---- | ---- | ---- |
| v8               | 13.10 Perform Application Layer Filtering<br>Perform application layer filtering. Example implementations include a filtering proxy, application layer firewall, or gateway. |      |      | ●    |
| v7               | 5.1 Establish Secure Configurations<br>Maintain documented, standard security configuration standards for all authorized operating systems and software.                     | ●    | ●    | ●    |

## Profile

Level 2