cis-tomcat9-v120-2-2

name	cis-tomcat9-v120-2.2
description	Alter the Advertised server.number String (Manual)
category	cis-tomcat
version	1.2.0
author	cyberstrike-official
tags	["cis","tomcat","linux","java","information-leakage","server-info"]
cis_id	2.2
cis_benchmark	CIS Apache Tomcat 9 Benchmark v1.2.0
tech_stack	["linux","tomcat","java"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

Alter the Advertised server.number String (Manual)

Description

The server.number attribute represents the specific version of Tomcat that is executing. This value is presented to Tomcat clients when connect.

Rationale

Advertising a valid server version may provide attackers with information useful for locating vulnerabilities that affect the server platform. Altering the server version string may increase the complexity for attackers to determine which vulnerabilities affect the server platform.

Audit Procedure

Perform the following to determine if the server.number value has been changed: Extract the ServerInfo.properties file and examine the server.number attribute.

$ cd $CATALINA_HOME/lib
$ jar xf catalina.jar org/apache/catalina/util/ServerInfo.properties
$ grep server.number org/apache/catalina/util/ServerInfo.properties

Remediation

Perform the following to alter the server version string that gets displayed when clients connect to the server.

1. Extract the ServerInfo.properties file from the catalina.jar file:

$ cd $CATALINA_HOME/lib
$ jar xf catalina.jar org/apache/catalina/util/ServerInfo.properties

2. Navigate to the util directory that was created

$ cd org/apache/Catalina/util

3. Open ServerInfo.properties in an editor
4. Update the server.number attribute

server.number=<someversion>

5. Update the catalina.jar with the modified ServerInfo.properties file.

$ jar uf catalina.jar org/apache/catalina/util/ServerInfo.properties

Default Value

The default value for the server.number attribute is a four part version number, such as 9.0.0.0.

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.