Patrick Dyroff. .

March Intensive:XSS Exploits

Patrick Dyroff

Sudikoff

http://www.ists.dartmouth.edu/images/Sudikoff_Lab.JPG

Sergey Bratus• ISTS' Chief Security Advisor and

a Postdoctoral Research Assistant Professor in the Computer Science Department at Dartmouth College

• Taught the “Computer Security and Privacy” course

• Undergraduate education at the Moscow Institute of Physics and Technology (AKA, Moscow Phystech), and his Ph.D. at Northeastern University (1999).

http://www.ists.dartmouth.edu/people/fellows/bratus.html

What is XSS?

• Cross-Site Scripting

• Webpage vulnerability

• Simple, Used often

• Code Injection

• Three types: Type 1, 2 … 0?

http://cdn.memegenerator.net/instances/400x/15481816.jpg

Type 1• Known as non-persistent or

reflected.

• The most common type.

• Arises when server-side scripts generate a page of results using the data from the web client for the user.

• An attacker could embed this URL in an email, posing a situation and enticing the victim to click on it

Type 2• Known as stored, persistent, or second

order

• Most powerful type of XSS attack

• Can be made when data provided to a web app by a user is stored in a database or file system and can be accessed later by different users

• Forums are a Type 2 targeted victim examples

Type 0• Known as DOM-based or Local XSS

• Very similar to the type 1 vulnerability

• The problem is also within a page’s client side script

• There is one key difference between the two

• This attack goes around the client-side sandbox, not only the cross domain, like other XSS attacks do

How can it be used?

• Cookies!!

• Allows access to previous sessions

• Certain logon information

• Worms, Phishing, Spamming, Oh My!

http://meowcheese.com/files/lolpics/2010/06/ok-ok-i-stole-a-cookie.jpg

Patches• All these examples can be

patched relatively easily

• Many possibilities that keep being found

• HTML or JavaScript escape function

Thanks for listening!

http://images.sodahead.com/profiles/0/0/2/8/9/6/8/4/1/Jazz_Hands_Cat-79814272162.jpeg