TITLE: Show In Browser 0.0.3 Ruby Gem /tmp file injection vulnerability.

  

  

  

  

DESCRIPTION: Opens arbitrary text in your browser

  

  

  

  

DETAILS: 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

10 

11 `open #{FILE_LOCATION}`

  

  

By a malicious user creating /tmp/browser.html first and repeatedly writing to it they can inject malicious html into 

  

  

  

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.