Cross Site Scripting and its Issues

Cross Site Scripting and its IssuesBy

Odion Oisamoje

What is XSS

Is a vulnerability that enables an attacker lure a computer user to download malicious JavaScript code from a trusted site.

Types of XSS

0Persistent Attack is stored on the website’s server. Do not have to go through a link

0Non-persistent Most common User has to go through a special link to be exposed Code does not get stored on the server

Types of XSS cont.

Figure 1: A typical reflected or non-persistent cross site scripting scenario

Type of XSS Cont.

0DOM-based An emerging area Attacker code does not have to pass though the server to

affect the visitor

How it Works

0http://www.youtube.com/watch?v=r79ozjCL7DA

Famous Attack

0 “In 2005, a MySpace user named Samy discovered a unique way to expand hi buddy list. Within 24 hours, the number of friends in his page grew from 73 to more than 1 million. He achieved this instant popularity by creating the first self-propagating cross-site scripting (XSS) worm and by exploiting the lax security in many Web browsers” (Monthie, 2008).

Prevention – Detection – Response

0Reduce Impact0Sanitize input0Work back to the source

Input sanitation and validation on JavaScript code0Be proactive

References

0 Monthie, B. (2008). What, who, when, where, why, how of XSS. Network World, 25(28), 26. Retrieved from EBSCOhost.

0 Cross-site Scripting (XSS). (2010, October 10). Retrieved April 15, 2011, from The Open Web Application Security Project (OWASP): https://www.owasp.org

Q & A