CVE-2022-25765 _ Command Injection in pdfkit

📅 [ Archival Date ]

Dec 7, 2022 7:52 PM

⚠️ [ ORIGIN SOURCE ]

https://security.snyk.io/vuln/SNYK-RUBY-PDFKIT-2869795

🏷️ [ Tags ]

pdfkitruby

✍️ [ Author ]

Benoit Côté-Jodoin

💣 [ PoC / Exploit ]

https://crash.link/cve-2022-25765

INTRODUCED: 14 JUN 2022

CVE-2022-25765

CWE-78

How to fix?
Upgrade pdfkit to version 0.8.7 or higher.

Overview

Affected versions of this package are vulnerable to Command Injection where the URL is not properly sanitized.

PoC:

An application could be vulnerable if it tries to render a URL that contains query string parameters with user input:

PDFKit.new("http://example.com/?name=#{params[:name]}").to_pdf

If the provided parameter happens to contain a URL encoded character and a shell command substitution string, it will be included in the command that PDFKit executes to render the PDF:

irb(main):060:0> puts PDFKit.new("http://example.com/?name=#{'%20`sleep 5`'}").command wkhtmltopdf --quiet [...] "http://example.com/?name=%20`sleep 5`" - => nil

Calling to_pdf on the instance shows that the sleep command is indeed executing:

PDFKit.new("http://example.com/?name=#{'%20`sleep 5`'}").to_pdf
# 5 seconds wait...

Of course, if the user can control completely the first argument of the PDFKit constructor, they can also exploit the command injection as long as it starts with "http":

PDFKit.new("http%20`sleep 5`").to_pdf

CVE-2022-25765 _ Command Injection in pdfkit

Overview

PoC:

References