mitigations.md

Mitigation Strategies Analysis for yarnpkg/berry

Mitigation Strategy: Implement Integrity Checks for .pnp.cjs

• Description:

  1. Generate .pnp.cjs Checksum: During the Yarn Berry build process (e.g., yarn install), after Yarn generates the .pnp.cjs file, calculate a cryptographic checksum (e.g., SHA-256) of this file.
  2. Store .pnp.cjs Checksum Securely: Store this checksum in a secure location, ideally separate from the .pnp.cjs file itself, such as in environment variables, a dedicated configuration file, or a secure vault accessible during deployment.
  3. Verification Script for .pnp.cjs: Create a script (e.g., a shell script or Node.js script) that runs specifically before the application starts using the Yarn Berry PnP mechanism in the target environment.
  4. Recalculate .pnp.cjs Checksum in Script: This script recalculates the checksum of the .pnp.cjs file in the target environment.
  5. Compare .pnp.cjs Checksums: The script compares the recalculated checksum with the securely stored checksum of the original .pnp.cjs file.
  6. Halt on .pnp.cjs Mismatch: If the checksums do not match, the script should halt the application startup process, preventing the application from running with a potentially tampered .pnp.cjs file, and log an alert.

• List of Threats Mitigated:

  • Supply Chain Attacks on Yarn Berry .pnp.cjs (High Severity): An attacker compromises the .pnp.cjs file, which is central to Yarn Berry's Plug'n'Play functionality, after it's generated but before deployment, injecting malicious code that will be executed by Node.js when using PnP.
  • Accidental Corruption of Yarn Berry .pnp.cjs (Medium Severity): Unintentional changes or corruption of the .pnp.cjs file during deployment or system administration, leading to application failures or unpredictable behavior due to a broken PnP setup.

• Impact:

  • Supply Chain Attacks on Yarn Berry .pnp.cjs (High Reduction): Directly prevents the application from using a modified .pnp.cjs file, effectively mitigating supply chain attacks that target this specific Yarn Berry component.
  • Accidental Corruption of Yarn Berry .pnp.cjs (Medium Reduction): Detects accidental corruption of the .pnp.cjs file, ensuring the application relies on a valid PnP configuration, improving stability and reducing unexpected errors related to Yarn Berry.

• Currently Implemented:

  • Partially Implemented: Checksum generation for .pnp.cjs is included in the CI/CD pipeline (Jenkinsfile, stage: "build"). The checksum is stored as an artifact in the CI/CD system.

• Missing Implementation:

  • .pnp.cjs Verification Script: A verification script specifically designed to check the .pnp.cjs checksum needs to be developed and integrated into the application startup process, ensuring it runs before any code relying on Yarn Berry PnP is executed.
  • Secure Storage Integration for .pnp.cjs Checksum: The verification script needs to be configured to securely retrieve the stored .pnp.cjs checksum from the CI/CD artifact storage or a more robust vault (e.g., HashiCorp Vault) to prevent tampering with the checksum itself.
  • Alerting System for .pnp.cjs Verification Failures: Integration with an alerting system (e.g., Slack, email, monitoring platform) is needed to immediately notify security and operations teams if the .pnp.cjs checksum verification fails, indicating a potential security incident or deployment issue related to Yarn Berry.

Mitigation Strategy: Restrict Access to .pnp.cjs

• Description:

  1. Identify Yarn Berry Runtime User/Process: Determine the specific user or process that Node.js will run under when executing the application using Yarn Berry PnP in the production environment. This user needs read access to .pnp.cjs.
  2. Set File Permissions for .pnp.cjs: Use file system commands (e.g., chmod, chown on Linux/Unix) to explicitly set permissions on the .pnp.cjs file, tailored for Yarn Berry's PnP usage.
     • Read-Only for Yarn Berry Runtime User: Grant only read access to the identified application runtime user/process.
     • No Write Access in Production: Crucially, remove write access for all users and processes in the production environment for .pnp.cjs. Write access should only be necessary during the controlled Yarn Berry build process.
  3. Verify .pnp.cjs Permissions: After setting permissions, rigorously verify them using ls -l (Linux/Unix) or equivalent commands to confirm that only the intended read-only permissions are applied to .pnp.cjs in production.
  4. Automate .pnp.cjs Permission Setting in Deployment: Integrate the permission setting steps into the deployment automation scripts (e.g., Ansible playbooks, Kubernetes manifests, Dockerfile) to ensure consistent and correct permissions are applied to .pnp.cjs across all deployments.

• List of Threats Mitigated:

  • Unauthorized Modification of Yarn Berry .pnp.cjs (Medium Severity): An attacker who gains unauthorized access to the production system might attempt to modify the .pnp.cjs file to inject malicious code or disrupt the application's dependency resolution managed by Yarn Berry PnP.
  • Privilege Escalation via Yarn Berry .pnp.cjs Modification (Medium Severity): If a vulnerability allows an attacker to execute code with the permissions of the application runtime user, restricting write access to .pnp.cjs prevents them from leveraging Yarn Berry's PnP to persistently alter the application's dependency structure for privilege escalation.

• Impact:

  • Unauthorized Modification of Yarn Berry .pnp.cjs (Medium Reduction): Significantly reduces the risk of unauthorized modification of the critical .pnp.cjs file by enforcing read-only access in production, making it much harder for attackers to tamper with Yarn Berry's PnP setup.
  • Privilege Escalation via Yarn Berry .pnp.cjs Modification (Medium Reduction): Limits the potential for privilege escalation by preventing attackers from persistently modifying the .pnp.cjs file to manipulate Yarn Berry's dependency resolution after gaining initial access.

• Currently Implemented:

  • Partially Implemented: Dockerfile sets a dedicated user and group for the application runtime, which is a good practice. However, explicit file permissions for .pnp.cjs are not currently set; default permissions are relied upon, which might not be sufficiently restrictive.

• Missing Implementation:

  • Explicit .pnp.cjs Permission Setting in Deployment Scripts: Deployment scripts (e.g., Ansible playbooks, Kubernetes manifests, Dockerfile) need to be updated to explicitly set read-only permissions for the designated application runtime user on the .pnp.cjs file during the deployment process.
  • Documentation and Procedures for .pnp.cjs Permissions: Clearly document the required file permissions for .pnp.cjs in production environments and incorporate these instructions into deployment procedures, security guidelines, and hardening checklists specific to Yarn Berry deployments.

Mitigation Strategy: Strictly Control and Vet Yarn Plugins (Berry Specific)

• Description:

  1. Yarn Plugin Inventory (Berry Focus): Create a detailed inventory of all Yarn Berry plugins currently used in the project's .yarnrc.yml configuration. Focus specifically on plugins that extend Yarn Berry's core functionality.
  2. Justification and Security Review for Yarn Berry Plugins: For each Yarn Berry plugin, document its precise purpose and rigorously justify its necessity within the Yarn Berry workflow. Conduct a focused security review of each plugin:
     • Source and Reputation (Berry Plugin Context): Verify the plugin's source (e.g., npm registry, GitHub repository, Yarn Plugin Registry if applicable) and critically assess the reputation and trustworthiness of the plugin's author/maintainer within the Yarn Berry ecosystem.
     • Security History (Berry Plugin Specific): Specifically check for any known vulnerabilities or security issues reported for that particular Yarn Berry plugin or related plugins from the same author.
     • Code Review (Berry Plugin Code): If feasible and especially for plugins that have significant impact on the Yarn Berry build process, perform a code review to understand the plugin's internal workings and identify potential security risks within the context of Yarn Berry's plugin architecture.
  3. Formal Approval Process for Yarn Berry Plugins: Establish a formal approval process specifically for adding new Yarn Berry plugins. This process must include a mandatory security review and clear justification demonstrating why the plugin is essential for the Yarn Berry workflow before it can be approved for use in the project.
  4. Yarn Berry Plugin Whitelist: Maintain a whitelist of approved Yarn Berry plugins. Only plugins on this whitelist should be permitted in the project's .yarnrc.yml configuration.
  5. Automated Checks for Yarn Berry Plugins (if possible): Explore or develop tools or scripts that can automatically check the .yarnrc.yml configuration to ensure that only whitelisted Yarn Berry plugins are being used and flag or prevent the use of any unapproved plugins in the project's Yarn Berry setup.

• List of Threats Mitigated:

  • Malicious Yarn Berry Plugins (High Severity): Using a compromised or intentionally malicious Yarn Berry plugin that could introduce vulnerabilities, backdoors, or exfiltrate sensitive build information during the Yarn Berry-managed build process.
  • Vulnerable Yarn Berry Plugins (Medium Severity): Using a legitimate but vulnerable Yarn Berry plugin that contains known security flaws that could be exploited to compromise the Yarn Berry build environment or the resulting application.
  • Supply Chain Attacks via Yarn Berry Plugins (High Severity): An attacker compromises the repository or update mechanism of a legitimate Yarn Berry plugin to distribute malicious versions to users, potentially affecting many projects relying on that plugin within the Yarn Berry ecosystem.

• Impact:

  • Malicious Yarn Berry Plugins (High Reduction): Significantly reduces the risk of using malicious Yarn Berry plugins by implementing rigorous vetting and approval processes specifically focused on these plugins.
  • Vulnerable Yarn Berry Plugins (Medium Reduction): Reduces the risk of using vulnerable Yarn Berry plugins by emphasizing security reviews and awareness of the security history of plugins within the Yarn Berry context.
  • Supply Chain Attacks via Yarn Berry Plugins (Medium Reduction): Reduces the risk of supply chain attacks targeting Yarn Berry plugins by promoting careful scrutiny of plugin sources and updates, although complete prevention of sophisticated attacks remains challenging.

• Currently Implemented:

  • Not Implemented: There is currently no formal vetting or approval process specifically for Yarn Berry plugins. Developers can add plugins to the .yarnrc.yml configuration without a mandatory security review.

• Missing Implementation:

  • Yarn Berry Plugin Inventory and Security Review: Conduct a dedicated review of all currently used Yarn Berry plugins in .yarnrc.yml and create a plugin inventory with justifications and security assessments specifically tailored to Yarn Berry plugin security.
  • Formal Yarn Berry Plugin Approval Process Definition: Define a clear and documented process for requesting, security-reviewing, and formally approving new Yarn Berry plugins before they can be added to the project's .yarnrc.yml configuration.
  • Yarn Berry Plugin Whitelist Creation: Establish a whitelist of approved Yarn Berry plugins based on the security review process, specifically for use within the .yarnrc.yml configuration.
  • Process Documentation and Training for Yarn Berry Plugins: Document the Yarn Berry plugin vetting and approval process and provide specific training to developers on these procedures, emphasizing the unique security considerations of Yarn Berry plugins.
  • Automation for Yarn Berry Plugin Whitelist Checks (Optional): Explore options for automating checks within the CI/CD pipeline or development environment to verify that only whitelisted Yarn Berry plugins are configured in .yarnrc.yml.

Mitigation Strategy: Implement Lockfile Integrity Checks (Yarn Berry yarn.lock)

• Description:

  1. Generate Yarn Berry Lockfile Checksum: During the Yarn Berry build process (e.g., yarn install), after Yarn generates or updates the yarn.lock file, calculate a cryptographic checksum (e.g., SHA-256) of this specific yarn.lock file.
  2. Store Yarn Berry Lockfile Checksum Securely: Store this checksum in version control alongside the yarn.lock file itself, or in a separate secure location if version control integrity is a primary concern. The key is to associate the checksum directly with the specific yarn.lock it represents.
  3. Verification in CI/CD Pipeline (Yarn Berry Context): In the CI/CD pipeline, specifically in stages that rely on Yarn Berry dependencies (e.g., build, test, deploy), recalculate the checksum of the yarn.lock file retrieved from version control.
  4. Compare Yarn Berry Lockfile Checksums: Compare the recalculated checksum with the stored checksum (either the one committed to version control or a separately stored checksum). Ensure the comparison is against the checksum generated for the correct yarn.lock file.
  5. Fail CI/CD on Yarn Berry Lockfile Mismatch: If the checksums do not match, immediately fail the CI/CD pipeline. This failure should clearly indicate potential tampering with the Yarn Berry yarn.lock file, requiring investigation before proceeding.
  6. Local Development Verification (Optional, Yarn Berry Focused): Consider implementing a pre-commit hook or a script that developers can run locally within their Yarn Berry development environment to verify the integrity of their yarn.lock file before committing changes, promoting consistent lockfile usage.

• List of Threats Mitigated:

  • Supply Chain Attacks on Yarn Berry yarn.lock (High Severity): An attacker compromises the yarn.lock file in version control or during the Yarn Berry development/build process, enabling them to introduce malicious dependencies or specific vulnerable versions that Yarn Berry will then install based on the modified lockfile.
  • Accidental Modification of Yarn Berry yarn.lock (Medium Severity): Unintentional changes to the yarn.lock file by developers or automated processes, leading to inconsistent Yarn Berry dependency resolutions across environments and potentially introducing unexpected dependency issues or vulnerabilities due to dependency drift in the Yarn Berry context.

• Impact:

  • Supply Chain Attacks on Yarn Berry yarn.lock (High Reduction): Effectively detects tampering with the Yarn Berry yarn.lock file in version control or during CI/CD, significantly reducing the risk of supply chain attacks that specifically target Yarn Berry's dependency resolution mechanism.
  • Accidental Modification of Yarn Berry yarn.lock (Medium Reduction): Detects accidental modifications to the Yarn Berry yarn.lock file, preventing inconsistent builds and dependency drift within the Yarn Berry environment, improving build reliability and security posture specifically related to Yarn Berry's dependency management.

• Currently Implemented:

  • Partially Implemented: The yarn.lock file is version controlled, which provides a basic level of historical integrity for Yarn Berry's dependency resolutions.

• Missing Implementation:

  • Checksum Generation and Storage for Yarn Berry yarn.lock: Checksum generation for the yarn.lock file needs to be implemented as part of the Yarn Berry build process. A straightforward approach is to commit the checksum to a separate file in version control (e.g., yarn.lock.sha256) alongside the yarn.lock file.
  • Verification in CI/CD Pipeline (Yarn Berry Focused Stages): Integrate the checksum verification step into the CI/CD pipeline stages that specifically utilize Yarn Berry dependencies (e.g., build, test, deploy stages that run yarn install or use Yarn Berry managed dependencies).
  • Pre-commit Hook (Optional, Yarn Berry Context): Implement a pre-commit hook that developers can use in their local Yarn Berry development environments to encourage local yarn.lock integrity checks before committing changes, reinforcing consistent lockfile practices within the Yarn Berry workflow.
  • Documentation and Procedures for Yarn Berry Lockfile Integrity: Document the yarn.lock integrity check process and explicitly include it in development and CI/CD procedures, emphasizing its importance for maintaining secure and consistent Yarn Berry dependency management.