🛡️ Sentinel: [HIGH] Add standard security headers

[Dexploarer]

🚨 Severity: HIGH
💡 Vulnerability: Missing security headers (X-Frame-Options, X-Content-Type-Options, etc.) which leaves the application vulnerable to Clickjacking and other attacks.
🎯 Impact: Attackers could frame the application to trick users (Clickjacking) or trick the browser into executing malicious scripts (MIME sniffing).
🔧 Fix: Implemented applySecurityHeaders in src/api/server.ts to enforce X-Frame-Options: DENY, X-Content-Type-Options: nosniff, and other best-practice headers on all responses.
✅ Verification: Created src/api/server.headers.test.ts to verify headers are correctly set. Ran full API test suite (src/api/) to ensure no regressions.

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PR created automatically by Jules for task 13619060532586196859 started by @Dexploarer

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[codereviewbot-ai]

Test Robustness:
The test only checks that certain headers are set, but does not verify that no additional headers are set. This could allow accidental or malicious changes to go unnoticed. Consider enhancing the test to assert that only the expected headers are set, for example by checking the number of calls to setHeader:

expect(res.setHeader).toHaveBeenCalledTimes(4);

This ensures that no extra headers are set.

[gemini-code-assist]

Summary of Changes

Hello @Dexploarer, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a high-severity security vulnerability by implementing standard security headers across the API. The changes introduce a dedicated function to set headers like X-Frame-Options and X-Content-Type-Options, mitigating risks such as Clickjacking and MIME sniffing, and include new tests to validate their correct application.

Highlights

• Security Headers Implementation: Introduced a new applySecurityHeaders function in src/api/server.ts to enforce critical security headers like X-Frame-Options, X-Content-Type-Options, Referrer-Policy, and Permissions-Policy on all API responses.
• Header Application: Integrated the applySecurityHeaders function into the handleRequest function within src/api/server.ts to ensure these headers are automatically applied to every incoming request.
• Test Coverage: Added a dedicated test file, src/api/server.headers.test.ts, to verify that the applySecurityHeaders function correctly sets the intended security headers, ensuring proper functionality and preventing regressions.

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Changelog

• src/api/server.headers.test.ts
  • Added a new test file to verify the applySecurityHeaders function.
• src/api/server.ts
  • Added applySecurityHeaders function to set standard security headers.
  • Called applySecurityHeaders within the handleRequest function to apply headers to all responses.

Activity

• PR was automatically created by Jules for a task started by @Dexploarer.

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[gemini-code-assist]

Code Review

This pull request is a great step towards improving the application's security by adding standard security headers. The implementation is clean, and the inclusion of unit tests is excellent. I've suggested some additional headers and improvements to make the security posture even stronger. Please see my detailed comments.

[gemini-code-assist]

This is a great start for adding security headers. To further improve security, I suggest adding a few more standard headers and using a more common value for Referrer-Policy.

• Referrer-Policy: strict-origin-when-cross-origin is a modern, secure default that is often more practical than no-referrer.
• X-XSS-Protection: 0 is recommended to disable the browser's deprecated XSS auditor.
• Content-Security-Policy: object-src 'none'; frame-ancestors 'none'; provides additional protection against embedding unwanted objects and clickjacking. frame-ancestors 'none' is the modern replacement for X-Frame-Options.
• Strict-Transport-Security (HSTS) enforces HTTPS, which is crucial for security.

Here is a suggested implementation:

export function applySecurityHeaders(res: http.ServerResponse): void {
  res.setHeader("X-Content-Type-Options", "nosniff");
  res.setHeader("X-Frame-Options", "DENY");
  res.setHeader("Referrer-Policy", "strict-origin-when-cross-origin");
  res.setHeader("Permissions-Policy", "interest-cohort=()");
  res.setHeader("X-XSS-Protection", "0");
  res.setHeader("Content-Security-Policy", "object-src 'none'; frame-ancestors 'none';");
  // HSTS tells the browser to always use HTTPS. Be cautious enabling this in development
  // if you are not using HTTPS locally.
  res.setHeader("Strict-Transport-Security", "max-age=31536000; includeSubDomains");
}

[gemini-code-assist]

After applying the suggested improvements to applySecurityHeaders, please update this test to assert that all the new security headers are being set correctly.

    expect(res.setHeader).toHaveBeenCalledWith("X-Content-Type-Options", "nosniff");
    expect(res.setHeader).toHaveBeenCalledWith("X-Frame-Options", "DENY");
    expect(res.setHeader).toHaveBeenCalledWith("Referrer-Policy", "strict-origin-when-cross-origin");
    expect(res.setHeader).toHaveBeenCalledWith("Permissions-Policy", "interest-cohort=()");
    expect(res.setHeader).toHaveBeenCalledWith("X-XSS-Protection", "0");
    expect(res.setHeader).toHaveBeenCalledWith("Content-Security-Policy", "object-src 'none'; frame-ancestors 'none';");
    expect(res.setHeader).toHaveBeenCalledWith("Strict-Transport-Security", "max-age=31536000; includeSubDomains");