Fix for CWE-352: Cross-Site Request Forgery (CSRF)

[asadeddin]

Corgea is an AI security engineer that fixes vulnerable code.

It issued this PR to fix a vulnerability for you to review.

See the issue and fix in Corgea.

Explanation of the issue

CWE-352: Cross-Site Request Forgery (CSRF)
The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.
When a web server is designed to receive a request from a client without any mechanism for verifying that it was intentionally sent, then it might be possible for an attacker to trick a client into making an unintentional request to the web server which will be treated as an authentic request. This can be done via a URL, image load, XMLHttpRequest, etc. and can result in exposure of data or unintended code execution.

Explanation of the fix

The fix involves implementing CSRF protection using the 'csurf' middleware and 'cookie-parser' in the Express.js server. This ensures that every client request is verified for authenticity.

• The 'cookie-parser' middleware is imported and used in the Express.js application. This middleware parses Cookie header and populates req.cookies with an object keyed by the cookie names.
• The 'csurf' middleware is also imported and used. This provides CSRF protection by generating a unique token for every session and validating it with every state-changing request.
• The CSRF token is attached to the response locals (res.locals._csrf) in a middleware function. This token is then available to the views, and can be included in forms or AJAX requests to ensure they are only accepted when the token matches the one generated by the server.
• The middleware function also calls the 'next()' function to ensure that the request-processing continues to the next middleware or route handler.

[corgea]

🐕 Corgea is suggesting a fix

Corgea would like fix:

• CWE-548: Exposure of Information Through Directory Listing with a severity of Medium.
• On file server.ts
• Severity: Medium

💬 Fix Explanation

The fix involves replacing the 'serveIndex' middleware with 'express.static' middleware in the '/ftp' route to prevent directory listing, thereby mitigating the information exposure risk.

• The 'serveIndex' middleware was previously used, which allowed directory listing and potentially exposed sensitive information.
• The fix replaces 'serveIndex' with 'express.static' middleware, which serves static files instead of directory listings.
• The 'index' option is set to 'false' in 'express.static' to prevent the automatic serving of the 'index.html' file, further securing the directory.

🪄 Fix suggestion

diff --git a/server.ts b/server.ts
index df537df..e7ab949 100644
--- a/server.ts
+++ b/server.ts
@@ -252,7 +252,7 @@ restoreOverwrittenFilesWithOriginals().then(() => {
 
   // vuln-code-snippet start directoryListingChallenge accessLogDisclosureChallenge
   /* /ftp directory browsing and file download */ // vuln-code-snippet neutral-line directoryListingChallenge
-  app.use('/ftp', serveIndexMiddleware, serveIndex('ftp', { icons: true })) // vuln-code-snippet vuln-line directoryListingChallenge
+  app.use('/ftp', serveIndexMiddleware, express.static('ftp', { index: false, icons: true })) // vuln-code-snippet vuln-line directoryListingChallenge
   app.use('/ftp(?!/quarantine)/:file', fileServer()) // vuln-code-snippet vuln-line directoryListingChallenge
   app.use('/ftp/quarantine/:file', quarantineServer()) // vuln-code-snippet neutral-line directoryListingChallenge