threat-modeling.md

Threat Model Analysis for yarnpkg/berry

Threat: 1. Compromised PnP Index File (.pnp.cjs)

• Threat: Compromised PnP Index File
• Description: An attacker modifies the .pnp.cjs file, a core component of Yarn Berry's Plug'n'Play. By injecting malicious code or altering module resolution paths within this file, they can execute arbitrary code within the application's context during module loading.
• Impact: Critical. Full application compromise, arbitrary code execution, data theft, denial of service due to malicious code execution during module resolution controlled by the compromised .pnp.cjs file.
• Affected Berry Component: Plug'n'Play Module Resolution, .pnp.cjs file.
• Risk Severity: Critical
• Mitigation Strategies:
  • Implement strict file system access controls to protect the .pnp.cjs file.
  • Use file integrity monitoring to detect unauthorized changes to .pnp.cjs.
  • Secure the Yarn installation process to prevent manipulation during installation that could lead to a compromised .pnp.cjs.

Threat: 2. Bugs in PnP Implementation

• Threat: PnP Implementation Vulnerabilities
• Description: Vulnerabilities exist within Yarn Berry's Plug'n'Play implementation itself. Attackers can exploit these bugs by crafting specific dependency structures or module requests that trigger unexpected behavior in PnP's core logic, potentially leading to arbitrary code execution or denial of service.
• Impact: High to Critical. Depending on the nature of the bug, impacts can range from denial of service and unexpected application behavior due to PnP malfunction, to arbitrary code execution if memory corruption or similar vulnerabilities are present in PnP's core logic.
• Affected Berry Component: Plug'n'Play Core Logic, Module Resolution Algorithm.
• Risk Severity: High (potentially Critical depending on bug)
• Mitigation Strategies:
  • Keep Yarn Berry updated to the latest stable version to benefit from bug fixes and security patches in the PnP implementation.
  • Monitor Yarn Berry security advisories and release notes for PnP related vulnerability disclosures.
  • Report any suspected PnP bugs to the Yarn Berry maintainers to contribute to the security of PnP.

Threat: 3. Tooling Incompatibility and PnP Bypass

• Threat: PnP Bypass via Incompatible Tooling
• Description: Attackers utilize tools that are not designed to work with Yarn Berry's Plug'n'Play and intentionally bypass PnP's module resolution mechanism. By using these tools to directly manipulate dependencies outside of PnP's control, they can introduce malicious packages or circumvent intended dependency isolation enforced by PnP.
• Impact: High. Bypassing PnP can lead to dependency confusion, installation of unexpected dependency versions, and introduction of vulnerabilities by circumventing PnP's intended security boundaries and dependency management.
• Affected Berry Component: Plug'n'Play Isolation, External Tooling Interaction.
• Risk Severity: High
• Mitigation Strategies:
  • Thoroughly audit and strictly control all tooling used within the development and deployment pipeline to ensure PnP compatibility and prevent bypass attempts.
  • Enforce the use of Yarn Berry for all dependency management tasks and restrict the use of tools that are known to be incompatible with or bypass PnP.
  • Consider using Yarn Berry's node-modules plugin only as a compatibility layer for specific tools if absolutely necessary, and carefully assess the security implications compared to pure PnP.

Threat: 4. Workspace Isolation Breakouts

• Threat: Workspace Isolation Breakout
• Description: An attacker exploits vulnerabilities in Yarn Berry's workspace feature, designed for monorepos, to break isolation between workspaces. By exploiting weaknesses in how Yarn Berry manages workspace boundaries, they can gain unauthorized access from one workspace to resources or dependencies of another, compromising multiple parts of the monorepo.
• Impact: High. Compromise of one workspace can lead to the compromise of other workspaces within the same monorepo, potentially escalating the impact of a security breach across the entire project due to broken workspace isolation.
• Affected Berry Component: Workspaces Isolation Logic, Inter-Workspace Communication.
• Risk Severity: High
• Mitigation Strategies:
  • Carefully review and rigorously test workspace configurations to ensure proper and effective isolation between workspaces.
  • Keep Yarn Berry updated to benefit from security patches specifically addressing workspace isolation vulnerabilities.
  • Implement workspace-specific security policies and access controls to further reinforce isolation at the application level, beyond Yarn Berry's features.

Threat: 5. Malicious Plugins

• Threat: Malicious Plugin Installation
• Description: A user is tricked into installing a malicious Yarn Berry plugin from an untrusted source. Once installed, the malicious plugin, which extends Yarn Berry's functionality, can execute arbitrary code within the Yarn Berry environment during various Yarn operations, potentially compromising the entire development environment and project.
• Impact: Critical. Full Yarn Berry environment and potentially system compromise, arbitrary code execution, data theft, manipulation of project dependencies and build processes due to malicious code execution within the Yarn plugin system.
• Affected Berry Component: Plugin Installation Mechanism, Plugin Execution Environment.
• Risk Severity: Critical
• Mitigation Strategies:
  • Strictly only install plugins from highly trusted and reputable sources.
  • Verify plugin integrity using checksums or signatures whenever available to ensure the plugin hasn't been tampered with.
  • Carefully review plugin code before installation, especially for plugins from less established or unknown sources, to identify any suspicious or malicious code.
  • Implement a mandatory plugin vetting process for your development team to ensure all installed plugins are reviewed and approved for security.
  • Consider using a plugin allowlist to explicitly restrict plugin installation to a predefined set of approved and vetted plugins.

Threat: 6. Vulnerabilities in Plugins

• Threat: Plugin Vulnerabilities
• Description: Installed Yarn Berry plugins, even from seemingly reputable sources, may contain unintentional security vulnerabilities due to coding errors or oversights. Attackers can exploit these vulnerabilities in plugins to compromise the Yarn Berry environment or projects that rely on these vulnerable plugins.
• Impact: High to Critical. Depending on the nature of the vulnerability within the plugin, impacts can range from denial of service and unexpected Yarn behavior to arbitrary code execution and system compromise due to exploitation of plugin vulnerabilities.
• Affected Berry Component: Plugin Code, Plugin Execution Environment.
• Risk Severity: High (potentially Critical depending on vulnerability)
• Mitigation Strategies:
  • Keep all installed plugins updated to the latest versions to benefit from security patches and bug fixes released by plugin authors.
  • Actively monitor plugin security advisories and release notes for any reported vulnerabilities and necessary updates.
  • Consider utilizing plugin security scanning tools, if available, to automatically detect known vulnerabilities in installed Yarn Berry plugins.
  • If feasible, contribute to the development or security auditing of plugins you rely on to improve their overall security posture.
  • Regularly review the list of installed plugins and remove any plugins that are no longer actively used or maintained, reducing the attack surface.

Threat: 7. Configuration Injection/Manipulation (.yarnrc.yml)

• Threat: .yarnrc.yml Configuration Manipulation
• Description: An attacker gains unauthorized write access to the .yarnrc.yml configuration file, which controls Yarn Berry's settings. By injecting malicious configuration settings into this file, they can alter Yarn Berry's behavior in harmful ways, potentially disabling security features, modifying dependency resolution, or even executing arbitrary commands during Yarn operations.
• Impact: High to Critical. Depending on the specific configuration settings manipulated, impacts can range from bypassing security features and altering dependency resolution to arbitrary command execution and exposure of sensitive information controlled by Yarn Berry configuration.
• Affected Berry Component: Configuration Loading, .yarnrc.yml file parsing.
• Risk Severity: High to Critical
• Mitigation Strategies:
  • Treat the .yarnrc.yml file as a highly sensitive configuration file and implement strict access controls to prevent unauthorized modifications.
  • If configuration is dynamically generated or influenced by external sources, rigorously validate and sanitize all configuration inputs to prevent injection attacks.
  • For sensitive settings, prefer using environment variables or secure configuration management systems instead of directly embedding them within the .yarnrc.yml file.
  • Implement file integrity monitoring for the .yarnrc.yml file to detect any unauthorized changes or tampering.

Threat: 8. Lockfile Poisoning/Manipulation (yarn.lock)

• Threat: yarn.lock Lockfile Poisoning
• Description: An attacker maliciously modifies the yarn.lock file, which is intended to ensure consistent dependency versions. By poisoning the lockfile, they can force the installation of malicious dependencies or specific vulnerable versions of legitimate dependencies into the project, bypassing the intended integrity and security of dependency locking.
• Impact: High. Introduction of malicious or vulnerable dependencies into the project, potentially leading to code execution, data theft, or exploitation of known vulnerabilities within the application due to compromised dependencies installed via the poisoned lockfile.
• Affected Berry Component: Lockfile Parsing, Dependency Installation from Lockfile.
• Risk Severity: High
• Mitigation Strategies:
  • Treat the yarn.lock file as a critical security asset and ensure it is committed to version control to track changes and facilitate rollback if needed.
  • Implement integrity checks and monitoring of the yarn.lock file for any unauthorized modifications or signs of tampering.
  • Secure the process of generating and updating yarn.lock files to prevent malicious actors from influencing the lockfile generation process.
  • Leverage Yarn Berry's built-in integrity checks and verification features for lockfiles to detect and prevent the use of manipulated lockfiles.
  • Regularly audit project dependencies and update them to patched versions to minimize the window of opportunity for exploiting vulnerabilities introduced through lockfile poisoning.