Cis Tomcat101 2.4

Disable X-Powered-By HTTP Header and Rename the Server Value for all Connectors (Automated)

Description

The xpoweredBy setting determines if Apache Tomcat will advertise its presence via the X-Powered-By HTTP header. It is recommended that this value be set to false. The server attribute overrides the default value that is sent down in the HTTP header further masking Apache Tomcat.

Rationale

Preventing Tomcat from advertising its presence in this manner may increase the complexity for attackers to determine which vulnerabilities affect the server platform.

Audit Procedure

Perform the following to determine if the server platform, as advertised in the HTTP Server header, has been changed:

1. Locate all Connector elements in $CATALINA_HOME/conf/server.xml.
2. Ensure each Connector that has the xpoweredBy attribute does NOT have it set to true.

Remediation

Perform the following to prevent Tomcat from advertising its presence via the X-PoweredBy HTTP header.

1. Add the xpoweredBy attribute to each Connector specified in $CATALINA_HOME/conf/server.xml. Set the xpoweredBy attributes value to false.

<Connector
...
xpoweredBy="false" />

Alternatively, ensure the xpoweredBy attribute for each Connector specified in $CATALINA_HOME/conf/server.xml is absent.

2. Add the server attribute to each Connector specified in $CATALINA_HOME/conf/server.xml. Set the server attribute value to anything except a blank string.

Default Value

The default value is false.

References

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

CIS Controls

v8:

• 16.7 Use Standard Hardening Configuration Templates for Application Infrastructure
  • Use standard, industry-recommended hardening configuration templates for application infrastructure components. This includes underlying servers, databases, and web servers, and applies to cloud containers, Platform as a Service (PaaS) components, and SaaS components. Do not allow in-house developed software to weaken configuration hardening.

v7:

• 13.2 Remove Sensitive Data or Systems Not Regularly Accessed by Organization
  • Remove sensitive data or systems not regularly accessed by the organization from the network. These systems shall only be used as stand alone systems (disconnected from the network) by the business unit needing to occasionally use the system or completely virtualized and powered off until needed.

Profile Applicability

• Level 2