# Cis Tomcat101 5.2

> Use LockOut Realms

- Skill: `cyberstrikeus/cis-tomcat101-5-2` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-tomcat101-5-2`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-tomcat101-5-2/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: cyberstrikeus (https://skillmd.com/u/cyberstrikeus)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/cyberstrikeus/cis-tomcat101-5-2

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# 5.2 Use LockOut Realms (Automated)

## Profile Applicability

• Level 2

## Description

A `LockOut` realm wraps around standard realms adding the ability to lock a user out after multiple failed logins.

## Rationale

Locking out a user after multiple failed logins slows down attackers from brute forcing logins.

## Audit Procedure

Perform the following to check to see if a `LockOut` realm is being used:

```bash
# grep "LockOutRealm" $CATALINA_HOME/conf/server.xml
```

## Remediation

Create a lockout realm wrapping the main realm similar to the example below:

```xml
<Realm className="org.apache.catalina.realm.LockOutRealm"
failureCount="3" lockOutTime="600" cacheSize="1000"
cacheRemovalWarningTime="3600">
  <Realm
className="org.apache.catalina.realm.DataSourceRealm"
dataSourceName="... />
</Realm>
```

## References

1. http://tomcat.apache.org/tomcat-9.0-doc/realm-howto.html
2. http://tomcat.apache.org/tomcat-9.0-doc/config/realm.html

## CIS Controls

**Controls Version: v8**

**Control:** 4 Secure Configuration of Enterprise Assets and Software

Establish and maintain the secure configuration of enterprise assets (end-user devices, including portable and mobile; network devices; non-computing/IoT devices; and servers) and software (operating systems and applications).

## Profile

Level 2