How can we Secure Jenkins

Authentication and Authorization

Authentication Approaches:

Jenkins presents a selection of inherent authentication methods, also referred to as 'Security Realms,' which encompass 'Delegate to servlet container' and 'Jenkins' user database.' However, to bolster security, it's advised to veer away from these built-in options and, instead, opt for third-party vendors like GitLab, Github, LDAP, SAML, or Google for centralised authentication. By adopting these alternatives, additional measures such as enforcing password complexity can be applied to mitigate the risk of unauthorised server access.

Should you opt for a temporary solution like 'Jenkins' user database,' it's recommended to deactivate the 'Allow users to sign up' feature and manage registered users manually.

Authorization Strategies:

Mirroring the previous section, Jenkins provides several default authorization methods, including 'Anyone can do anything,' 'Legacy mode,' and 'Logged-in users can do anything.' However, a more secure approach involves leveraging plugins to implement more sophisticated authorization techniques.

Prominent plugins like Matrix Authorization Strategy and Role-based Authorization Strategy are noteworthy for offering enhanced flexibility in enforcing the Principle of Least Privilege (PoLP). These plugins empower administrators to define privileges for anonymous users, authenticated users, or specific individuals, even allowing the configuration of privileges per project or the assignment of custom roles to users. This tutorial elucidates the process of role definition through these plugins.

While GitHub-based and GitLab-based authorization is feasible using the aforementioned plugins, caution is advised due to the potential lack of granular permission definition and the potential for misconfiguration."

Role-Based Access Control (RBAC)

Role-Based Access Control (RBAC) is a security mechanism that allows administrators to define and manage user access to resources based on their roles and responsibilities within an organisation. RBAC ensures that users have the appropriate level of access to perform their tasks while preventing unauthorised access to sensitive information and functions. Here's how RBAC works and its benefits:

Key Components of RBAC:

• Roles: Roles represent specific job functions or responsibilities within an organisation. Examples of roles could be "Administrator," "Developer," "Tester," etc.
• Permissions: Permissions are the actions or operations that users with a particular role are allowed to perform. These could include creating jobs, running builds, managing configurations, and more.
• Users: Users are individuals within the organisation who are assigned to specific roles based on their responsibilities.

How RBAC Works:

• Role Assignment: Administrators assign users to specific roles based on their job functions. Each role has associated permissions that dictate what actions users with that role can perform.
• Access Control: Users are only granted access to the resources and actions that align with their assigned roles. They cannot perform actions beyond their permissions.
• Flexible Access Control: RBAC allows for fine-grained control over access. Users can have multiple roles, and roles can be customised to fit the organisation's needs.

Benefits of RBAC:

• Security Enhancement: RBAC helps prevent unauthorised access by ensuring that users have the minimum necessary permissions to perform their tasks.
• Simplified Management: Instead of managing permissions for individual users, administrators manage roles, which makes access control more efficient.
• Scalability: As an organisation grows, RBAC scales well. New users can be assigned roles with predefined permissions, reducing the risk of errors.
• Compliance and Auditing: RBAC facilitates compliance with regulatory requirements by controlling access and allowing audit trails to be maintained.

Plugin Management and Security

Plugin management and security are critical aspects of maintaining a secure and stable Jenkins environment. Plugins can provide valuable functionality but can also introduce security risks if not managed properly. Here's how to handle plugin management and security effectively:

Plugin Management:

• Use Trusted Sources: Download and install plugins only from the official Jenkins Plugin Index or other trusted sources. Avoid third-party or unverified plugins.
• Regular Updates: Keep plugins up to date with the latest versions that include security patches and bug fixes.
• Remove Unused Plugins: Uninstall or disable plugins that are no longer needed to reduce potential attack surfaces.
• Test in Isolation: Test new plugins in an isolated environment before deploying them to production to identify any compatibility or security issues.

Plugin Security:

• Check Plugin Ratings: Before installing a plugin, check its ratings, reviews, and usage statistics on the Jenkins Plugin Index. Higher-rated plugins are generally more reliable and secure.
• Secure Credentials: If plugins require access to sensitive information (e.g., API tokens), use the Jenkins Credentials plugin to securely manage and provide credentials.
• Monitor Plugin Activity: Implement monitoring to detect any abnormal activity or behaviour from plugins that could indicate a security breach.
• Penetration Testing: Include plugin security assessment in your penetration testing efforts to identify vulnerabilities.

Secure Credentials Handling

Securely handling credentials is a critical aspect of maintaining the overall security of your Jenkins environment. Credentials can include sensitive information such as passwords, API keys, SSH keys, and other authentication tokens. Jenkins provides a built-in plugin called "Credentials Plugin" that helps manage and protect sensitive information. Here's how to securely handle credentials in Jenkins:

• Use the Credentials Plugin: Jenkins' Credentials Plugin allows you to securely store and manage various types of credentials, such as usernames, passwords, SSH keys, and secret text.
• Secret Text and Secret File: Use the "Secret Text" credential type for simple text-based secrets (e.g., API keys) and the "Secret File" credential type for files (e.g., SSH keys).
• Credentials Binding Plugin: Utilise the "Credentials Binding" plugin to inject credentials as environment variables into your build steps. This ensures that sensitive information is not exposed in plain text.
• Encrypted Storage: The Credentials Plugin encrypted stored credentials, adding an extra layer of security to sensitive information.
• Multi-Factor Authentication (MFA): Use multi-factor authentication for Jenkins administrators to further protect access to sensitive areas.

Securing Jenkins Jobs and Pipelines

Securing Jenkins jobs and pipelines is crucial to ensure the confidentiality, integrity, and availability of your software development processes and the sensitive information involved. Here are some best practices for securing Jenkins jobs and pipelines:

Pipeline Script Security:

• Avoid using the evaluate step in your pipelines, as it can execute arbitrary code.
• Enable the "Pipeline Syntax" feature to validate your pipeline scripts and prevent common security issues.
• Implement a code review process for pipeline changes to catch security vulnerabilities.

Agent Security:

• Ensure agents (nodes/agents) used for running builds are securely configured and regularly updated.
• Use agent-to-master and agent-to-agent communication security mechanisms like SSH or JNLP (Java Web Start) with appropriate authentication and encryption.

Job Isolation:

• Use the "Pipeline" or "Multibranch Pipeline" project type to define pipelines in code, ensuring version control and reproducibility.
• Isolate job workspaces and environments using Docker containers or virtualization technologies.

Secure Shell (SSH) Access:

• Restrict SSH access to the Jenkins server.
• Disable direct root login and enforce key-based authentication for SSH access.

Logging and Monitoring:

• Enable logging for Jenkins server and agents, and regularly review logs for suspicious activities.
• Set up monitoring and alerting for any unusual or unauthorised access patterns.

Firewall and Network Security:

• Use firewalls to restrict incoming and outgoing network traffic to and from the Jenkins server.
• Isolate the Jenkins server from public networks and apply network segmentation if needed.

Script Approval

Jenkins has a feature called "Script Approval" that is designed to enhance the security of your pipeline scripts by requiring manual approval for potentially unsafe or untrusted script code to run. This feature helps prevent unauthorised or malicious code from being executed without proper review.

Here's how the Script Approval process works:

• Approval Request: When a blocked script attempts to execute, Jenkins will halt the execution and present a notification or log message indicating that a script requires approval.
• Manual Approval: An administrator or user with appropriate permissions can then access the "Script Approval" section in the Jenkins web interface. This section lists all pending script approvals.
• Review and Approval: In the "Script Approval" section, the administrator or user can review the pending scripts, see the code that needs approval, and decide whether to approve or reject the script.
• Whitelist: If the script is deemed safe, the administrator can approve it, and Jenkins will add the script to a whitelist. This allows the approved script to run without further interruption.

Audit Logging

Audit logging is a critical aspect of securing Jenkins and maintaining accountability and transparency in your software development process. It involves recording and tracking events related to user actions, system activities, and configuration changes within the Jenkins environment. Audit logs are essential for identifying security breaches, troubleshooting issues, and ensuring compliance with regulatory requirements. Here's how to implement effective audit logging in Jenkins:

• Enable Jenkins Audit Logging: Depending on your Jenkins version and setup, audit logging may be available as a built-in feature or may require the installation of plugins. Look for plugins like "Audit Trail" or "Audit Log" in the Jenkins Plugin Index.
• Configure Audit Log Parameters: Once you've installed the appropriate plugin, configure audit log parameters. These parameters typically include options for choosing which events to log, specifying log formats, defining log retention policies, and setting up log rotation.
• Set Log Levels and Retention: Configure log levels to capture varying degrees of detail. You might want to capture detailed logs for critical events and higher-level summaries for less important activities. Define how long log entries should be retained before being automatically purged.
• Centralised Logging: Consider sending audit logs to a centralised log management system or SIEM (Security Information and Event Management) tool. This centralization can aid in analysis, correlation, and long-term storage of logs.
• Secure Access to Logs: Restrict access to audit logs to authorised personnel only. Apply proper authentication and authorization mechanisms to prevent unauthorised users from tampering with or viewing the logs.

Jenkins Master and Agent Security

Securing both the Jenkins master and its agent nodes (formerly known as slaves) is essential for maintaining the integrity, confidentiality, and availability of your Jenkins environment. Here are specific measures you can take to enhance the security of both components:

Jenkins Master Security:

Access Control:

• Restrict access to the Jenkins master server. Allow only authorised personnel to access the Jenkins web interface and administrative features.
• Use strong authentication mechanisms such as LDAP, Active Directory, or OAuth.
• Implement role-based access control (RBAC) to define user permissions.

Plugin Management:

• Keep Jenkins and its plugins up to date with the latest security patches.
• Disable or remove unused plugins to reduce potential attack vectors.
• Network Security: Isolate the Jenkins master from public networks using firewalls or network segmentation.
• Use HTTPS for secure communication between users and the Jenkins web interface.

Script Approval: Use the Script Approval feature to prevent unsafe scripts from executing without manual approval.

Jenkins Agent Node Security:

Agent-to-Master Communication:

• Use secure communication mechanisms between agent nodes and the Jenkins master. SSH and JNLP (Java Web Start) are common options.
• Ensure proper authentication and encryption for agent-to-master communication.

Agent Configuration:

• Securely configure agent nodes by disabling unnecessary services and limiting the software installed on them.
• Update agents with the latest security patches and updates.
• Access Control: Limit access to agent nodes. Agents should be accessible only to authorised users and the Jenkins master.
• Use unique authentication credentials for each agent.

Agent Workspace Isolation:

• Run builds in isolated workspaces using technologies like Docker or virtual machines.
• Restrict access to agent workspaces to prevent unauthorised access.

Secure Execution Environment: Implement user and process isolation on agent nodes to prevent privilege escalation.

Agent Authentication:

• Use SSH keys or other secure authentication methods for agent-to-master communication.
• Disable password-based authentication for agent nodes.

Using External Identity Providers

Using external identity providers (IdPs) for authentication in Jenkins is a secure and convenient way to manage user access and authentication. Instead of creating and managing Jenkins-specific user accounts, you can leverage existing user identities from external sources like LDAP, Active Directory, OAuth, SAML, or OpenID Connect. This approach centralises user management, enhances security, and simplifies the login experience for users. Here's how to set up external identity providers in Jenkins:

• Choose an External Identity Provider: Determine which external identity provider you want to use. Common options include LDAP, Active Directory, OAuth providers like Google or GitHub, SAML, and OpenID Connect.
• Install and Configure Plugins: Jenkins provides various plugins to integrate with different identity providers. Install the appropriate plugin that corresponds to your chosen IdP. For example, use the "LDAP" plugin for LDAP authentication or the "GitHub OAuth" plugin for GitHub OAuth authentication.
• Configure Identity Provider Settings: For each plugin, configure the settings required to connect Jenkins to your chosen identity provider. These settings may include the IdPs URL, credentials, group mappings, and attribute mappings.
• Test the Integration: After configuring the plugin, test the integration by attempting to log in to Jenkins using your external identity provider's credentials. Ensure that the login process works as expected.
• Multi-Factor Authentication (MFA): If your identity provider supports it, consider enabling multi-factor authentication for an extra layer of security.
• Error Handling and Logging: Configure appropriate error handling and logging settings in Jenkins to capture authentication-related events and issues.

Security Plugins and Tools

There are several security plugins and tools available for Jenkins that can help enhance the security of your Jenkins environment and ensure the safety of your software development pipeline. Here are some security plugins and tools you might consider integrating into your Jenkins setup:

• Credentials Binding Plugin: This plugin allows you to securely inject credentials (such as passwords, SSH keys, and certificates) into your builds and pipelines. It helps prevent exposing sensitive information in your code.
• OWASP Dependency-Check Plugin: This plugin integrates with the OWASP Dependency-Check tool, which scans your project's dependencies for known vulnerabilities in third-party libraries.
• Static Code Analysis Plugins: Plugins like "Checkstyle," "FindBugs," and "SpotBugs" can perform static code analysis to identify coding issues, potential vulnerabilities, and bad practices in your codebase.
• OWASP ZAP Plugin: This plugin integrates with the OWASP ZAP (Zed Attack Proxy) tool, allowing you to perform dynamic security testing by scanning your application for common vulnerabilities during the build process.
• Active Directory and LDAP Plugins: These plugins allow Jenkins to authenticate users against your organisation's Active Directory or LDAP server, ensuring centralised authentication and user management.
• GitHub OAuth Plugin: If you use GitHub, this plugin enables you to authenticate users via GitHub OAuth, leveraging GitHub accounts for Jenkins authentication.
• SonarQube Scanner Plugin: The SonarQube Scanner plugin integrates Jenkins with SonarQube, a platform for continuous code quality inspection. It can identify security vulnerabilities, code smells, and technical debt.
• Kubernetes Plugin (for Container Security): If you're using Kubernetes for container orchestration, this plugin can help ensure that your containers are scanned for vulnerabilities before being deployed.

Continuous Security Assessments

Continuous security assessments are a crucial component of maintaining a secure software development process and environment. These assessments involve continuously monitoring, identifying, and addressing security vulnerabilities and risks in your applications, infrastructure, and processes throughout the entire development lifecycle. Here's how to implement continuous security assessments effectively:

• Automated Security Scanning: Integrate automated security scanning tools into your CI/CD pipeline. These tools can perform static code analysis, dynamic application scanning, container security scanning, and more. Examples include SAST (Static Application Security Testing) and DAST (Dynamic Application Security Testing) tools.
• Infrastructure as Code (IaC) Security: Assess the security of your infrastructure by using tools that scan your IaC templates (e.g., Terraform, CloudFormation) for misconfigurations and security issues. This ensures that your cloud infrastructure is set up securely.
• Container Security: If you use containers, incorporate container security scanning tools that analyse container images for vulnerabilities, misconfigurations, and compliance issues.
• Regular Penetration Testing: Conduct periodic penetration testing to simulate real-world attacks and identify vulnerabilities that automated tools might miss. This can help validate the effectiveness of your security measures.
• Security Code Review: Include security code reviews as part of your development process. Reviewers should look for common security issues and coding best practices.
• Runtime Application Protection: Deploy tools that provide runtime protection, monitoring application behaviour for anomalous activities and blocking potentially malicious actions.
• Threat Modelling: Regularly update your threat models to reflect changes in your application and its environment. This helps identify potential attack vectors and informs security assessments.
• Integration with Bug Tracking: Integrate security findings with your bug tracking system, ensuring that identified vulnerabilities are appropriately tracked and addressed.

Best Practices for Jenkins Security

Securing Jenkins is essential to protect your software development pipeline, sensitive data, and the overall integrity of your environment. Here are some best practices for Jenkins security:

• Use Strong Authentication: Employ strong authentication mechanisms such as LDAP, Active Directory, or OAuth to ensure only authorised users can access Jenkins.
• Implement Role-Based Access Control (RBAC): Use RBAC to define and enforce user roles and permissions. Grant access only to the resources and actions necessary for each user's role.
• Use Secure Password Management: Avoid using default passwords and ensure that strong passwords are used for all accounts, including administrative ones.
• Secure Plugins: Keep Jenkins plugins up to date and only install plugins from trusted sources. Disable or remove unused plugins.
• Network Security: Isolate Jenkins from public networks, use firewalls to control incoming and outgoing traffic, and secure network communication.
• External Identity Providers: Integrate Jenkins with external identity providers for centralised user authentication and management.
• Secure Plugins and Tools: Choose and configure security plugins and tools to scan code, dependencies, and infrastructure for vulnerabilities.
• Automated Security Gates: Use automation to prevent code with security issues from progressing through the CI/CD pipeline.
• Incident Response Plan: Develop and maintain an incident response plan to handle security breaches and incidents effectively.