How to Improve Jenkins Security

Jenkins is a key part of many software teams’ toolchains. It helps automate builds, tests, and deployments. Yet, like any system, it’s not without its risks. If you don’t secure it the right way, you could make your whole process weak. That’s why it’s vital to know how to improve Jenkins security. Let’s explore how you can make your Jenkins setup strong and safe.

Table of Contents

Why Jenkins Security Matters

Jenkins is a popular open-source automation server. It helps with continuous integration and continuous delivery (CI/CD). But its popularity also makes it a target. If a bad actor gets into your Jenkins setup, they can cause real harm. They could tamper with your builds, steal data, or even stop your workflows.

Here are a few reasons why security is so important in Jenkins:

Access to sensitive data: Jenkins often handles credentials, API keys, and other secret information. These need extra protection.
Code tampering: If someone changes a build, they can inject bad code into your software. This could lead to security issues for your users.
System compromise: A breach in Jenkins can give attackers control over other systems in your network.
Business disruption: Downtime due to a security issue can cost your company a lot of money.
Reputational damage: A security breach can make your customers lose faith in your brand.

The truth is, securing Jenkins is not an option. It’s a must for any team that uses it.

Common Jenkins Security Risks

Before you improve Jenkins security, you need to know what threats you face. Here are some common risks to watch out for:

Default settings

Jenkins comes with some defaults that are not safe for use. Things like open access ports and weak passwords can make you an easy target.

Plugin vulnerabilities

Jenkins plugins add new functions, but they may also have security flaws. If you don’t keep them up to date, you may be open to known exploits.

Weak access control

Not limiting who can access Jenkins can cause trouble. People who don’t need access may make changes they should not, or might be a source of leaks if they are hacked.

Lack of encryption

If your data is not encrypted while it is being moved or stored, it could get into the wrong hands. This includes login data, and other vital info.

Unsecured scripts

Custom scripts in Jenkins can also be a risk if not handled with care. They can have flaws or may not be kept secure from outside access.

Missing audit logs

Without good logs, it’s hard to find out who did what. It’s also hard to detect and fix problems quickly.

Human error

Even with good systems, human error still plays a part. Bad passwords, or not following good practices can cause big risks.

How to Improve Jenkins Security: Best Practices

Now, let’s talk about how to improve Jenkins security in detail. Here are some best practices to protect your Jenkins setup:

Enable Authentication and Authorization

One of the first steps is to make sure only those who should have access, do. Jenkins has several ways to do this.

Use Built-In Security

Jenkins has its own security setup that helps with user and group access control. The built-in function is good for smaller teams. Here’s how to use it:

Go to Manage Jenkins and then Configure Global Security.
Find the Security Realm section.
Select Jenkins’ own user database. This lets you create and manage users directly in Jenkins.
Then find the Authorization section.
Select Matrix-based security. This lets you set access rights for each user and group.
Click Save.

With these settings, you can assign user rights. Some can have full access while others have view-only.

Connect to an external system

For bigger teams, external systems may work better. You can use LDAP, Active Directory, or OAuth 2.0. Here’s how to set up LDAP for example:

Go to Manage Jenkins then Configure Global Security.
Find the Security Realm area.
Choose LDAP.
Enter your LDAP server’s info. This includes the server address, port, and login credentials.
Test your setup to make sure it works.
Set up Authorization settings.
Click Save.

Doing this means Jenkins will use your LDAP info for access. This makes it easy to handle users in one place.

Implement Role-Based Access Control (RBAC)

RBAC limits what users can do based on their role. This way, you give the least access needed to do the job. For example, you can use the Role-Based Authorization Strategy plugin. To use it:

Go to Manage Jenkins then Manage Plugins.
Look for and install the Role-Based Authorization Strategy plugin.
Go to Manage Jenkins then Configure Global Security.
Pick Role-Based Strategy in the Authorization area.
Create roles for users, like admins, devs, or testers.
Assign rights to each role. For instance, the admin role can have full access while developers can only run builds and tests.
Assign users to the roles.
Click Save.

RBAC gives you more control over user access.

Keep Jenkins and Plugins Up to Date

Software updates often include security fixes. It is important to keep your Jenkins server and plugins updated.
Here’s how to do this:

Go to Manage Jenkins then Manage Plugins.
Go to the Updates tab.
Check the list for any updates.
Click the box next to the updates you want.
Click Download now and install after restart.
Restart Jenkins to make the updates go live.

Make it a habit to check for updates. New security fixes are important to keep you safe.

Use Strong Credentials

Passwords are like a lock on your front door. If they are easy to guess, you are not secure. Here are ways to use strong credentials:

Avoid Default Passwords

Default passwords are easy to find out. When setting up new accounts, always make up a strong, unique password.

Use a Password Manager

Password managers help with safe passwords. They create hard-to-guess passwords and store them in a secure way.

Set Password Policies

Set up password policies that force users to use strong passwords. This means needing things like a mix of uppercase and lowercase letters, numbers, and special symbols.

Enable HTTPS

HTTPS encrypts data when it is being sent between your browser and the Jenkins server. This protects things like passwords from being seen if someone is watching. To set it up:

Get an SSL certificate. You can get one for free from Let’s Encrypt.
Set up your web server with the SSL certificate.
Go to Manage Jenkins then Configure System.
Change the Jenkins URL to start with https:// instead of http://.
Click Save.

When using HTTPS, you add a layer of security to your setup.

Secure Sensitive Data

Jenkins deals with sensitive data, like API keys and passwords. It is important to keep this data safe.

Use the Credentials Plugin

The Credentials Plugin lets you store and handle secrets safely. Here is how to use it:

Go to Manage Jenkins then Manage Credentials.
Pick the scope where you want to keep your credentials, like the system or a folder.
Click Add Credentials.
Select the credential type. This can include username/password, SSH key, or secret text.
Add the needed info.
Click OK.

Now, in your builds, you can get these credentials without showing them in your scripts or configs.

Use Environment Variables

You can also use environment variables to manage your secrets. These variables can be set in the Jenkins settings. That makes it easy to use them in your builds without putting the actual values in your code:

Go to Manage Jenkins then Configure System.
Find the Global properties section.
Check the box for Environment variables.
Add your key-value pairs for the variables. For instance, you can add an API_KEY for the key and the real API key for the value.
Click Save.

You can now use these variables in your builds like $API_KEY.

Implement Secret Masking

Secret masking prevents secrets from showing in build logs. It can make a big difference in keeping data safe. To set it up:

Go to Manage Jenkins then Configure System.
Find the Global properties section.
Click Environment variables.
Check the box for Mask passwords.
Add a regex (regular expression) pattern to find and hide sensitive data.
Click Save.

Now, secrets that match the pattern will show in the logs as ******.

Limit Access to the Jenkins CLI and API

Jenkins has a command-line interface (CLI) and an API. They help automate tasks. But if they are not protected, they can be used by bad actors to get into your system. Here’s how to limit access to them:

Disable Unused CLI Commands

Jenkins CLI comes with a set of commands. But not all are needed. Here’s how to disable commands you do not use:

Go to Manage Jenkins then Script Console.
Run a Groovy script that disables the unused commands. Here’s one example to disable the shutdown command:

“`groovy
import jenkins.model.*

Jenkins.instance.getDescriptor(“hudson.cli.CLICommand”)
.removeCommandClass(“hudson.cli.ShutdownCommand”)
“`
3. Click Run to make the changes go live.

When you limit commands, you lower your risk.

Use API Tokens

API tokens allow for safer access to the Jenkins API. Instead of using a username and password for API requests, you can use these tokens, which can be revoked if they are leaked. Here’s how to generate them:

Log in to Jenkins with your account.
Go to your user profile.
Click Configure.
Find the API Token area.
Click Add new Token.
Add a name for the token.
Click Generate.
Copy the token and keep it in a secure spot.

Now, when you need to access the API, you can use the token rather than a password.

Regularly Audit Jenkins

Auditing helps you find problems and make sure things are secure. It helps with:

Enable Audit Logging

Jenkins provides audit logs that track changes. You can use the Audit Trail plugin to keep track of what is happening in your setup. Here is how to install and use it:

Go to Manage Jenkins then Manage Plugins.
Look for and install the Audit Trail plugin.
Go to Manage Jenkins then Configure System.
Find the Audit Trail section.
Pick what logs you want to see, like user access or setting changes.
Set where to save the logs.
Click Save.

With logs set up, you can keep a watch on what is happening and spot security issues.

Review User Access

Check who has access to Jenkins. Look for any users who should not be there or who have extra access.

Check Build Jobs

Look at your build jobs for any strange things. This may include odd changes or scripts you don’t know.

Monitor Plugin Updates

Keep a close watch on plugin updates. Make sure they are from a good source. Also, make sure they are up to date to prevent known security issues.

Restrict Network Access

Limiting network access helps keep out unauthorized users. You can set up firewalls to allow only trusted sources to reach your Jenkins setup. To do it:

Set up a firewall to block all incoming connections to the Jenkins server.
Set up a whitelist of IP addresses that can have access. This should include your own team’s IP address, and any systems that need to connect with Jenkins.
Also, set up network segmentation to keep the Jenkins server away from other systems.

With these settings in place, you add a layer of security and stop outside access.

Secure Jenkins Agents

Jenkins agents run your jobs. You need to secure them just as much as the main server.

Use Secure Protocols

When agents connect to the Jenkins server, make sure they use secure protocols like SSH, or JNLP over HTTPS.

Limit Agent Access

Give agents only the access they need to do their jobs. Do not let them access other systems on your network.

Keep Agents Up to Date

As with the Jenkins server, always update the agents to prevent security issues.

Secure Custom Scripts

Custom scripts can be a source of security issues. Here are some ways to secure them:

Code Reviews

Always have someone else look at your scripts before you use them. They can find code issues and bad code.

Input Validation

Make sure the script checks any data coming in. This way, you prevent bad data from causing problems.

Least Privilege

Only give your scripts the rights they need to work. If they do not need to change the file system, then don’t let them.

Backup Jenkins Data

Backups help you recover in case something goes wrong. Make sure you back up the Jenkins data on a regular schedule. This includes the config files, job setup, and other settings. To set up backups:

Go to Manage Jenkins then Backup Manager.
Set up where to store your backup files. This should be on a secure location.
Set up how often to run backups.
Click Save.

Make sure to test your backups to see if you can restore data.

Educate your team

Security is also about knowledge. Make sure your team knows the risks, and how to prevent them. Provide them with a training.

Security Practices

Teach your team how to use strong credentials, and spot phishing emails, and other risks.

How to Secure Builds

Teach them how to write secure build scripts. Also teach them how to handle secrets in a safe way.

How to Report Issues

Make it easy to report security issues. Let them know they will not be punished if they report a problem.

Tools and Plugins to Enhance Jenkins Security

Jenkins has many plugins that can help to improve Jenkins security. Here are some of them:

Role-Based Authorization Strategy: Helps you set up role-based access to your Jenkins set up.
Credentials Plugin: Used to manage and store your secrets, like API keys and passwords.
Audit Trail Plugin: Helps with keeping track of system changes. It helps to monitor events and detect security issues.
OWASP Dependency-Check Plugin: Checks your project for any known security issues that might exist in your software dependencies.
Static Analysis Plugins (like FindBugs, PMD, Checkstyle): These scan your code for possible security risks, bad practices, and style problems.
Kubernetes Plugin: Helps you make builds and run deployments on Kubernetes in a safe way.
Active Directory Plugin: Helps manage access by connecting Jenkins to your company’s Active Directory.
LDAP Plugin: Helps connect to an LDAP server to make it easy to manage users in one place.
Email Extension Plugin: Set up extra options for sending notifications by email, to always be aware of what’s happening.
Build Pipeline Plugin: Helps you organize complex build flows, by making sure each part runs in the right way.
Multibranch Plugin: Helps with managing builds for different branches of your code.
GitHub Branch Source Plugin: Makes the use of builds and webhooks easier for GitHub repos.
Bitbucket Branch Source Plugin: Does the same for Bitbucket repos.
Git Plugin: Allows for using Git for builds.

Using the correct tools and plugins can help with securing Jenkins and automating the process.

Jenkins Hardening Checklist

Here is a quick checklist to ensure Jenkins security:

[ ] Enable authentication and authorization using an external system or RBAC.
[ ] Update Jenkins and all the plugins.
[ ] Use strong credentials and manage them with a password manager.
[ ] Enable HTTPS to encrypt data in transit.
[ ] Manage sensitive data with the Credentials plugin and environment variables.
[ ] Mask sensitive data in logs.
[ ] Limit access to the Jenkins CLI and API using API tokens.
[ ] Enable audit logging.
[ ] Review user access, builds and updates regularly.
[ ] Restrict network access to trusted sources.
[ ] Use secure protocols and limit access for your agents.
[ ] Secure custom scripts with reviews and input validation.
[ ] Set up regular backups of your Jenkins data.
[ ] Educate your team on security risks and practices.

Securing Your CI/CD Pipeline With Jenkins

Improving Jenkins security is not a one-time thing. It is an ongoing job that needs time and effort. By using these best practices, you can make your Jenkins setup much stronger and more reliable. This will help make your CI/CD pipeline safer and protect your software development process. It is important to keep in mind that security is a team effort, and every member of your team must do their part. By putting security first, you can have a great CI/CD workflow with Jenkins, which can lead to a much safer product.