security.adoc

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Table of Contents

• Access Control
• Protect users of Jenkins from other threats
• Disabling Security

In the default configuration of Jenkins 1.x, Jenkins does not perform any security checks. This means the ability of Jenkins to launch processes and access local files are available to anyone who can access Jenkins web UI and some more.

Securing Jenkins has two aspects to it.

• Access control, which ensures users are authenticated when accessing Jenkins and their activities are authorized.

• Protecting Jenkins against external threats

Access Control

You should lock down the access to Jenkins UI so that users are authenticated and appropriate set of permissions are given to them. This setting is controlled mainly by two axes:

• Security Realm, which determines users and their passwords, as well as what groups the users belong to.

• Authorization Strategy, which determines who has access to what.

These two axes are orthogonal, and need to be individually configured. For example, you might choose to use external LDAP or Active Directory as the security realm, and you might choose "everyone full access once logged in" mode for authorization strategy. Or you might choose to let Jenkins run its own user database, and perform access control based on the permission/user matrix.

• Quick and Simple Security --- if you are running Jenkins like java -jar jenkins.war and only need a very simple setup

• Standard Security Setup --- discusses the most common setup of letting Jenkins run its own user database and do finer-grained access control

• Apache frontend for security --- run Jenkins behind Apache and perform access control in Apache instead of Jenkins

• Authenticating scripted clients --- if you need to programmatically access security-enabled Jenkins web UI, use BASIC auth

• Matrix-based security|Matrix-based security --- Granting and denying finer-grained permissions

In addition to access control of users, access control for builds limits what builds can do, once started.

Protect users of Jenkins from other threats

There are additional security subsystems in Jenkins that protect Jenkins and users of Jenkins from indirect attacks.

The following topics discuss features that are off by default. We recommend you read them first and act on them immediately.

• CSRF Protection --- prevent a remote attack against Jenkins running inside your firewall. This feature is off by default in Jenkins 1.x and when upgrading to 2.x.

• Security implication of building on master --- protect Jenkins master from malicious builds

• Slave To Master Access Control --- protect Jenkins master from malicious build agents

• Securing JENKINS_HOME --- protect Jenkins from users with local access

The following topics discuss other security features that are on by default. You’ll only need to look at them when they are causing problems.

• Configuring Content Security Policy --- protect users of Jenkins from malicious builds

• Markup formatting --- protect users of Jenkins from malicious users of Jenkins

Disabling Security

One may accidentally set up a security realm / authorization in such a way that you may no longer be able to reconfigure Jenkins.

When this happens, you can fix this by the following steps:

1. Stop Jenkins (the easiest way to do this is to stop the servlet container.)

2. Go to $JENKINS_HOME in the file system and find config.xml file.

3. Open this file in the editor.

4. Look for the <useSecurity>true</useSecurity> element in this file.

5. Replace true with false

6. Remove the elements authorizationStrategy and securityRealm

7. Start Jenkins

8. When Jenkins comes back, it will be in an unsecured mode where everyone gets full access to the system.

If this is still not working, trying renaming or deleting config.xml.