How it was found

I would like to report Stored XSS in module "http_server". It allows to inject malicious scripts in the file name, store them on the server, then execute these scripts in the browser via the XSS vulnerability.

Module

• module name: http_server
• version: 1.0.12
• npm page: https://www.npmjs.com/package/http_server

Module Description

一个静态服务器 means "a static server"

Module Stats

• [14] downloads in the last week
• [116] downloads in the last month

Vulnerability

Vulnerability Description

This XSS vulnerability occurs due to the module represents filename(s) in HTML without any sanitization in listing directory page. In a result, any malicious scripts which are injected and stored on the server, would be executed in the client's browser.

Steps To Reproduce:

• Install the module

npm install -g http_server

• In the directory which will be served via http_server, create file with following names in directories ~/Desktop/:

" onmouseover=alert(1) "

or

<img src=x onmouseover=alert(1)>

{F489070}

• Run 'http_server in "~/Desktop" directory :

root@kali:~/Desktop# http_server
server running is :http://localhost:8888

• Open http://localhost:8888/ {F489069}
• When mouseover event is triggered on BOTH 2 payloads, a message will be popup via XSS vulnerability. {F489071}

Patch

User input should be properly sanitized and filtered both at the client and server side. Dangerous characters such as < > ' " % ; ) ( & + should either be disallowed or HTML encoded before displaying them on screen.

Supporting Material/References:

• Linux kali 4.15.0-kali2-amd64
• node 10.15.3
• npm 6.9
• Firefox ESR 52.7.3 (64-bit)

Wrap up

• I contacted the maintainer to let them know: N
• I opened an issue in the related repository: N

Impact

It allows to inject malicious scripts in the file name, store them on the server, then execute these scripts in the browser via the XSS vulnerability.