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attack-surface.md

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Attack Surface Analysis for jenkinsci/job-dsl-plugin

Attack Surface: DSL Script Injection and Unsafe Script Execution

  • Description: The execution of untrusted or maliciously crafted Groovy DSL scripts can lead to arbitrary code execution on the Jenkins master.
  • Job-DSL Plugin Contribution: The plugin's core functionality is to execute Groovy DSL scripts to define Jenkins jobs. This inherently introduces the risk of script injection if these scripts are not handled securely. The plugin provides mechanisms to load and execute scripts, making it the direct enabler of this attack surface.
  • Example: A developer configures a Job DSL seed job to fetch a DSL script from a public, uncontrolled Git repository. An attacker compromises this repository and injects malicious Groovy code into the DSL script. When Jenkins executes this script, the malicious code runs on the Jenkins master, potentially installing backdoors or exfiltrating secrets.
  • Impact:
    • Remote Code Execution (RCE) on Jenkins Master
    • Data Exfiltration (credentials, secrets, job configurations)
    • Denial of Service (DoS)
    • Privilege Escalation
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Source DSL scripts from trusted and controlled repositories only. Use private repositories with access controls.
    • Implement strict input validation and sanitization if DSL scripts are generated dynamically. Avoid constructing scripts from untrusted user input.
    • Utilize code review processes for all DSL scripts before they are used in production. Have a security-focused review to identify potential malicious code.
    • Employ static analysis tools and linters on DSL scripts to detect potential vulnerabilities or suspicious code patterns.
    • Apply principle of least privilege to Jenkins users and roles. Limit who can manage DSL seed jobs and trigger DSL script execution.

Attack Surface: Access Control and Authorization Bypass related to DSL Script Execution

  • Description: Weak or misconfigured access controls around DSL script execution and management can allow unauthorized users to create, modify, or delete Jenkins jobs, bypassing intended security policies.
  • Job-DSL Plugin Contribution: The plugin introduces new functionalities for programmatic job management. If the authorization checks for these functionalities are insufficient or bypassed, it creates a new attack vector. The plugin's permission model needs to be correctly integrated with Jenkins' security realm.
  • Example: A user with "Job/Build" permissions is able to trigger a DSL seed job that is configured to create or modify jobs. Due to insufficient permission checks within the Job DSL plugin, this user can effectively gain "Job/Configure" or even "Job/Administer" level access to jobs they shouldn't normally be able to manage, by manipulating the DSL script.
  • Impact:
    • Unauthorized Job Creation, Modification, or Deletion
    • Configuration Tampering of existing jobs
    • Abuse of Jenkins resources through creation of malicious jobs
    • Disruption of CI/CD pipelines
  • Risk Severity: High
  • Mitigation Strategies:
    • Enforce strict access control policies for triggering DSL seed jobs and managing DSL script seeds. Use Jenkins' role-based access control (RBAC) effectively.
    • Regularly review and audit permissions related to the Job DSL plugin and DSL seed jobs. Ensure permissions are aligned with the principle of least privilege.
    • Carefully configure Jenkins security realm and project-based security. Ensure DSL script execution respects these configurations.
    • Avoid granting overly permissive permissions to users or roles related to DSL script management.

Attack Surface: Plugin Specific Vulnerabilities (Bugs in the Job DSL Plugin Code)

  • Description: Vulnerabilities within the Job DSL plugin's code itself, such as code injection, XSS, CSRF, insecure deserialization, or path traversal, can be exploited to compromise Jenkins.
  • Job-DSL Plugin Contribution: As a software plugin, the Job DSL plugin is susceptible to common software vulnerabilities. Bugs in its Groovy code, UI components, or data handling logic can introduce new attack vectors.
  • Example: A vulnerability exists in the Job DSL plugin's handling of user-provided input when processing DSL scripts. An attacker crafts a specially formatted DSL script that exploits this vulnerability, leading to remote code execution when the plugin parses and executes the script, even if the script itself is seemingly benign.
  • Impact:
    • Remote Code Execution (RCE) on Jenkins Master
    • Information Disclosure
    • Account Takeover (via XSS or CSRF)
    • Denial of Service (DoS)
  • Risk Severity: High to Critical
  • Mitigation Strategies:
    • Keep the Job DSL plugin updated to the latest version. Plugin updates often include security patches for known vulnerabilities.
    • Monitor security advisories and vulnerability databases (e.g., NVD, Jenkins Security Advisories) for reported issues in the Job DSL plugin. Subscribe to security mailing lists.
    • Follow secure coding practices when contributing to or extending the Job DSL plugin.
    • Consider using a Web Application Firewall (WAF) in front of Jenkins to detect and block common web attacks, including some plugin-related exploits.

Attack Surface: Configuration and Misuse of DSL Script Seeds

  • Description: Insecure configuration or management of DSL Script Seeds, which define the source of DSL scripts, can lead to the execution of malicious scripts and unauthorized job modifications.
  • Job-DSL Plugin Contribution: The plugin relies on DSL Script Seeds to locate and load DSL scripts. Misconfiguration of these seeds directly impacts the security of the job definition process. The plugin's seed configuration mechanisms are the point of entry for this attack surface.
  • Example: A DSL Script Seed is configured to point to a public Git repository without authentication. An attacker gains write access to this public repository and modifies the DSL script. When Jenkins processes this seed, it fetches and executes the attacker's modified script, leading to malicious job definitions being created or existing jobs being altered.
  • Impact:
    • Loading and execution of malicious DSL scripts
    • Unauthorized modification of job definitions
    • Compromise of job configuration integrity
    • Potential for wider Jenkins compromise depending on the malicious script's actions
  • Risk Severity: Medium to High
  • Mitigation Strategies:
    • Secure DSL Script Seed locations using appropriate authentication and authorization mechanisms. Use private repositories with access controls and authentication.
    • Implement mechanisms to verify the integrity and authenticity of DSL scripts loaded from seeds. Use signed commits in Git, checksum verification, or other integrity checks.
    • Restrict access to managing and modifying DSL Script Seeds to authorized personnel only. Apply principle of least privilege to seed management.
    • Regularly audit DSL Seed configurations to ensure they are secure and point to trusted sources.
    • Consider using immutable infrastructure for DSL script storage where possible. This can prevent unauthorized modifications.