Ecosyste.ms: Advisories

Security Advisories: GSA_kwCzR0hTQS0zNDJxLTJtYzItNWdtcM4AA95a

@jmondi/url-to-png enables capture screenshot of localhost web services (unauthenticated pages)

Summary

The maintainer been contemplating whether FTP or other protocols could serve as useful functionalities, but there may not be a practical reason for it since we are utilizing headless Chrome to capture screenshots. The argument is based on the assumption that this package can function as a service.

The package includes an ALLOW_LIST where the host can specify which services the user is permitted to capture screenshots of. By default, capturing screenshots of web services running on localhost, 127.0.0.1, or the [::] is allowed.

The maintainer is of the opinion that the package should also have a blacklist due to a potential vulnerability (or rather design oversight). If someone hosts this on a server, users could then capture screenshots of other web services running locally.

Unless this is strictly for web pages. Something similar here: https://github.com/follow-redirects/follow-redirects/issues/235 (localhost is intended for end users or hosts to deny, and the package is for HTTP/HTTPS.)

This is marked as a LOW since the maintainer is not sure if this is a vulnerability, but it's still best to highlight it. :)

PoC

Have a service like so running locally:

const http = require("http")

const server = http.createServer((req, res) => {
  console.log("Received headers:", req.headers)
  res.writeHead(200, { "Content-Type": "text/plain" })
  res.end("Something private! But Hello from Server 2 :)")
})

server.listen(3001, () => {
  console.log("Server two running on http://localhost:3001")
})

Run the package in dev mode, pnpm dev. Feed these URLs:

http://localhost:3089/?url=http://[::]:3001&width=4000
http://localhost:3089/?url=http://localhost:3001&width=4000
http://localhost:3089/?url=http://127.0.01:3001&width=4000

Impact

Disclose internal web services?

Permalink: https://github.com/advisories/GHSA-342q-2mc2-5gmp
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS0zNDJxLTJtYzItNWdtcM4AA95a
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: 4 months ago
Updated: 5 days ago

CVSS Score: 3.7
CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Identifiers: GHSA-342q-2mc2-5gmp, CVE-2024-39919
References:

• https://github.com/jasonraimondi/url-to-png/security/advisories/GHSA-342q-2mc2-5gmp
• https://github.com/jasonraimondi/url-to-png/commit/f62ff40403ffa1781459d6be8d97b8035888c00c
• https://nvd.nist.gov/vuln/detail/CVE-2024-39919
• https://github.com/advisories/GHSA-342q-2mc2-5gmp

Repository: https://github.com/jasonraimondi/url-to-png
Blast Radius: 1.0

Affected Packages