Skip to content

Latest commit

 

History

History
73 lines (62 loc) · 6.89 KB

threat-modeling.md

File metadata and controls

73 lines (62 loc) · 6.89 KB

Threat Model Analysis for denoland/deno

Threat: Malicious Third-Party Module (Spoofing/Tampering)

  • Description: An attacker publishes a malicious module to a public registry (e.g., deno.land/x) or compromises a legitimate module's repository. The attacker might mimic a popular module's name (typosquatting) or inject malicious code into an existing module's update. The malicious code, leveraging Deno's URL-based import system, could steal data, install backdoors, or perform other harmful actions. This is critical because Deno's core design relies on remote module fetching.
  • Impact:
    • Data breaches (credentials, sensitive information).
    • System compromise (remote code execution).
    • Denial of service.
    • Cryptocurrency mining.
    • Reputational damage.
  • Affected Component: Deno's module import system (URLs, import statements), Deno's cache. This is a core Deno component.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Use Lock Files: Always use deno.lock to pin module versions and ensure integrity. Regularly update and audit the lock file. This is crucial for mitigating Deno's URL-based imports.
    • Import Maps: Use import maps to alias module URLs to specific, trusted locations, preventing typosquatting. This directly addresses the URL-based nature of Deno imports.
    • Vendoring: For critical dependencies, consider vendoring (copying the source code into your project) to eliminate reliance on external servers, mitigating the risk of remote code changes.
    • --check flag: Use deno run --check ... to type-check all code, including remote modules, before execution. This leverages Deno's built-in type checking.

Threat: Module Tampering in Cache (Tampering)

  • Description: An attacker gains access to the system where Deno is running and modifies the cached module files in the DENO_DIR. This exploits Deno's caching mechanism, which is a core part of how it manages modules. The attacker could inject malicious code that would be executed the next time the module is loaded.
  • Impact:
    • Execution of arbitrary malicious code.
    • Data breaches.
    • System compromise.
  • Affected Component: Deno's module cache (DENO_DIR) - a fundamental part of Deno's operation.
  • Risk Severity: High
  • Mitigation Strategies:
    • Secure DENO_DIR: Ensure the Deno cache directory has restrictive permissions (read-only for most users, write access only for the Deno user). This directly protects Deno's caching mechanism.
    • Read-Only Filesystem (Production): If feasible, mount the cache directory as read-only in production environments. This prevents any modification of Deno's cached modules.
    • Immutable Deployments: Use containerization (Docker) or other immutable deployment methods to prevent post-deployment modification of dependencies, including those in Deno's cache.

Threat: Unsafe --allow-run Usage (Elevation of Privilege)

  • Description: The --allow-run permission, a Deno-specific feature, is used without sufficient restrictions, allowing a malicious module to execute arbitrary commands on the host system. This is a direct exploitation of a Deno permission.
  • Impact:
    • Complete system compromise (remote code execution with the privileges of the Deno process).
    • Data breaches.
    • Installation of malware.
  • Affected Component: Deno's --allow-run permission - a core part of Deno's security model.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Avoid --allow-run if Possible: Explore alternative solutions that don't require executing arbitrary subprocesses.
    • Strict Whitelisting: If --allow-run is necessary, use a whitelist of allowed commands and arguments, rather than a blacklist. Be extremely specific. This directly controls the Deno permission.
    • Sandboxing: Use containers (Docker) or other sandboxing technologies to isolate the subprocesses executed by --allow-run, mitigating the impact of a compromised --allow-run permission.
    • Least Privilege: Run the Deno process with the lowest possible privileges.

Threat: Deno Runtime Vulnerability (Elevation of Privilege/Information Disclosure/Denial of Service)

  • Description: A security vulnerability is discovered in the Deno runtime itself (the deno executable). This is a direct threat to the core of Deno. This could allow an attacker to bypass the permission system, execute arbitrary code, or cause a denial of service.
  • Impact: Varies depending on the vulnerability, but could range from information disclosure to complete system compromise.
  • Affected Component: The Deno runtime itself (the deno executable) - the very foundation of the system.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Keep Deno Updated: Regularly update to the latest stable version of Deno to receive security patches. This is the primary defense against runtime vulnerabilities.
    • Monitor Security Advisories: Subscribe to Deno's security announcements and mailing lists.
    • Security Audits: Consider professional security audits that specifically target the Deno runtime.

Threat: Overly Permissive Permissions (Information Disclosure/Elevation of Privilege)

  • Description: The application is run with unnecessarily broad permissions (e.g., --allow-all, --allow-read, --allow-env without restrictions). A malicious module (or even a bug in your own code) can then access sensitive files, environment variables, or network resources.
  • Impact:
    • Data leakage (sensitive files, environment variables).
    • Potential for privilege escalation if a module can access resources that allow it to execute arbitrary code.
  • Affected Component: Deno's permission system (flags like --allow-read, --allow-write, --allow-net, --allow-env, --allow-run).
  • Risk Severity: High
  • Mitigation Strategies:
    • Principle of Least Privilege: Grant only the specific permissions required. Use granular permissions (e.g., --allow-read=/path/to/specific/file instead of --allow-read).
    • Permission Auditing: Regularly review and audit the permissions granted to your application.
    • Automated Permission Analysis: (Future) Tools that can analyze code and suggest minimal required permissions.
    • Secrets Management: Avoid storing sensitive information directly in environment variables; use a dedicated secrets management solution.