mitigations.md

Mitigation Strategies Analysis for markedjs/marked

Mitigation Strategy: Strict marked Configuration and Sanitization within marked

1. Mitigation Strategy: Strict marked Configuration and Sanitization within marked

• Description:

  1. Disable Deprecated sanitize: If you are using an older version of marked (prior to v5), explicitly set sanitize: false in the marked options. This prevents reliance on the outdated and less secure built-in sanitization. Do not use sanitize: true.
  2. Enable mangle: Set mangle: true in the marked options. This obfuscates email addresses rendered from Markdown, making them harder for bots to harvest. Example: marked.parse(markdownString, { mangle: true });
  3. Custom sanitizer Function (Pre-v5): If using a marked version before v5, and only if you cannot upgrade, define a custom sanitizer function. This function receives the already rendered HTML and should return the sanitized HTML. Strongly consider using a library like DOMPurify within this function. Example:

     marked.parse(markdownString, {
       sanitizer: function(html) {
         return DOMPurify.sanitize(html); // Use DOMPurify here!
       }
     });

     • Critical Note: If you are using marked v5 or later, this approach is not recommended. Rely on external sanitization with DOMPurify after marked has rendered the HTML.
  4. Review and Restrict Extensions: If you use marked extensions (using marked.use()), thoroughly review the source code of each extension. Ensure that any HTML generated by the extension is properly sanitized. If the extension generates HTML, you must sanitize it, ideally using DOMPurify, within the extension's code.
  5. Review and Sanitize Custom Renderers: If you override marked's default renderers (e.g., to customize how links or images are rendered), you are completely responsible for sanitizing the HTML output of your custom renderers. Use DOMPurify within the renderer function to sanitize any user-provided data (like URLs or image alt text). Example:

     const renderer = {
       link(href, title, text) {
         const sanitizedHref = DOMPurify.sanitize(href, { ALLOWED_TAGS: ['a'], ALLOWED_ATTR: ['href'] });
         return `<a href="${sanitizedHref}">${text}</a>`;
       }
     };
     marked.use({ renderer });

• List of Threats Mitigated:

  • XSS (Severity: Medium): By disabling the deprecated sanitize and carefully reviewing/sanitizing extensions and renderers, you reduce the attack surface within marked itself. However, this is not a replacement for a dedicated HTML sanitizer like DOMPurify.
  • Email Harvesting (Severity: Low): mangle: true helps prevent automated email address scraping.
  • Vulnerabilities in Extensions/Renderers (Severity: Variable - depends on the extension/renderer): Careful review and mandatory sanitization within custom extensions and renderers are crucial to prevent them from introducing vulnerabilities.

• Impact:

  • XSS: Risk reduced from Medium to Low only when combined with external sanitization. Without external sanitization, the risk remains significant.
  • Email Harvesting: Risk reduced from Low to Very Low.
  • Vulnerabilities in Extensions/Renderers: Risk depends entirely on the quality of the review and the thoroughness of the sanitization within the extension/renderer code.

• Currently Implemented:

  • mangle: true is set globally in frontend/config/markedConfig.js.
  • The deprecated sanitize option is not used (explicitly set to false).
  • A custom link renderer (in frontend/components/MarkdownRenderer.js) attempts to sanitize the href attribute (but should be using DOMPurify).

• Missing Implementation:

  • A comprehensive review of all marked extensions has not been performed. This is a critical gap.
  • The image renderer does not sanitize the src or alt attributes. This is a potential XSS vulnerability.
  • The custom link renderer should be updated to use DOMPurify for sanitization, rather than any custom sanitization logic.
  • No custom sanitizer function is defined (which is correct for newer marked versions, but highlights the reliance on external sanitization).

Mitigation Strategy: Regular Updates of marked

2. Mitigation Strategy: Regular Updates of marked

• Description:

  1. Automated Dependency Checks: Use tools like npm audit or yarn audit to automatically check for known vulnerabilities in marked during builds and deployments. Configure these tools to fail the build if vulnerabilities are found.
  2. Scheduled Manual Checks: Even with automated checks, perform periodic manual checks for updates to marked on its GitHub repository or official website.
  3. Security Advisories: Subscribe to security advisories and mailing lists related to marked to receive timely notifications of vulnerabilities.
  4. Rapid Update Process: Establish a clear and documented process for quickly updating marked to a patched version when a vulnerability is disclosed.

• List of Threats Mitigated:

  • Known Vulnerabilities in marked (Severity: Variable - depends on the specific vulnerability): Staying up-to-date ensures you have the latest security patches, addressing known vulnerabilities.
  • Zero-Day Vulnerabilities (Severity: High): While you cannot prevent zero-day vulnerabilities, a rapid update process minimizes the window of exposure after a vulnerability is publicly disclosed.

• Impact:

  • Known Vulnerabilities: Risk reduced from Variable to Low (assuming prompt updates are applied).
  • Zero-Day Vulnerabilities: Impact is mitigated by reducing the time your application is vulnerable.

• Currently Implemented:

  • npm audit is run as part of the CI/CD pipeline.

• Missing Implementation:

  • No formal process or schedule for manual checks for marked updates.
  • No subscriptions to security advisories specifically for marked.
  • The update process for marked is not clearly documented and may not be rapid enough.