CVE-2024-39919

@jmondi/url-to-png is an open source URL to PNG utility featuring parallel rendering using Playwright for screenshots and with storage caching via Local, S3, or CouchDB. 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. If someone hosts this project on a server, users could then capture screenshots of other web services running locally. This issue has been addressed in version 2.1.1 with the addition of a blocklist. Users are advised to upgrade. There are no known workarounds for this vulnerability.

@jmondi/url-to-png is an open source URL to PNG utility featuring parallel rendering using Playwright for screenshots and with storage caching via Local, S3, or CouchDB. 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. If someone hosts this project on a server, users could then capture screenshots of other web services running locally. This issue has been addressed in version 2.1.1 with the addition of a blocklist. Users are advised to upgrade. There are no known workarounds for this vulnerability.

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

<img width="622" alt="image" src="https://github.com/jasonraimondi/url-to-png/assets/42532003/21f1c883-ba00-4a15-83b8-922484fa4c2b">

Impact

Disclose internal web services?

@jmondi/url-to-png is an open source URL to PNG utility featuring parallel rendering using Playwright for screenshots and with storage caching via Local, S3, or CouchDB. 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. If someone hosts this project on a server, users could then capture screenshots of other web services running locally. This issue has been addressed in version 2.1.1 with the addition of a blocklist. Users are advised to upgrade. There are no known workarounds for this vulnerability.

@jmondi/url-to-png is an open source URL to PNG utility featuring parallel rendering using Playwright for screenshots and with storage caching via Local, S3, or CouchDB. 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. If someone hosts this project on a server, users could then capture screenshots of other web services running locally. This issue has been addressed in version 2.1.1 with the addition of a blocklist. Users are advised to upgrade. There are no known workarounds for this vulnerability.

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

<img width="622" alt="image" src="https://github.com/jasonraimondi/url-to-png/assets/42532003/21f1c883-ba00-4a15-83b8-922484fa4c2b">

Impact

Disclose internal web services?