Threat Model Analysis for prettier/prettier

Threat: Malicious Package Substitution (Dependency Confusion/Typosquatting)

Description: An attacker publishes a malicious package to a public registry (e.g., npm) with a name similar to prettier (e.g., pretiier, prettier-pro). A developer mistakenly installs this malicious package instead of the legitimate one. The malicious package mimics Prettier's functionality but also includes malicious code designed to execute during the formatting process.
- Impact:
  - Code modification: The malicious package could subtly alter the codebase during formatting, introducing vulnerabilities or backdoors.
  - Data exfiltration: The malicious package could steal sensitive information accessible during the build process (though ideally, secrets should not be present).
  - System compromise: The malicious package could execute arbitrary code on the developer's machine or the build server, potentially leading to a full system compromise.
- Affected Prettier Component: The entire prettier package (the imposter package) is affected, impacting all modules and functions.
- Risk Severity: Critical
- Mitigation Strategies:
  - Package-lock Files: Always use and commit package-lock.json (npm), yarn.lock (Yarn), or pnpm-lock.yaml (pnpm).
  - Manual Verification: Carefully review the package name and version before installing.
  - Private Registry: Use a private package registry to control the source of dependencies.
  - SCA Tools: Employ Software Composition Analysis (SCA) tools.

Threat: Compromised Prettier Plugin

Description: An attacker publishes a malicious Prettier plugin or compromises a legitimate, existing plugin. This plugin, when used as part of the Prettier formatting process, executes malicious code.
- Impact:
  - Code modification: The plugin could inject malicious code or subtly alter existing code during formatting.
  - Data exfiltration: The plugin could steal sensitive information accessible during the build.
  - System compromise: The plugin could execute arbitrary code with the privileges of the user running Prettier.
- Affected Prettier Component: The specific malicious plugin and any Prettier core functions that interact with the plugin API (prettier.format, plugin loading mechanisms).
- Risk Severity: High
- Mitigation Strategies:
  - Plugin Vetting: Carefully review the source code, author, and community reputation of any Prettier plugin.
  - Limit Plugin Usage: Minimize the number of plugins used.
  - Code Review: Treat plugin code as part of your codebase.
  - Sandboxing (Advanced): Consider running Prettier and its plugins in a sandboxed environment.

Threat: Post-Installation Tampering of Prettier Executable

Description: After a legitimate installation of Prettier, an attacker gains access to the developer's machine or the build server and directly modifies the installed Prettier files within the node_modules directory, injecting malicious code.
- Impact:
  - Code modification: The tampered Prettier executable could inject malicious code or alter existing code.
  - Data exfiltration: The tampered executable could steal sensitive information.
  - System compromise: The tampered executable could execute arbitrary code.
- Affected Prettier Component: Any of the core Prettier modules (e.g., index.js, parser files) within the node_modules/prettier directory.
- Risk Severity: High
- Mitigation Strategies:
  - File Integrity Monitoring (FIM): Use FIM to detect unauthorized modifications to the node_modules directory.
  - Regular Re-installation: Regularly delete and re-install dependencies from a clean state (rm -rf node_modules && npm install).
  - Read-Only node_modules (Advanced): Make the node_modules directory read-only after installation.
  - Strong Access Controls: Implement strong access controls for developer machines and CI/CD pipelines.