1. Cross-Site Scripting
Travis Deyarmin

2. What is XSS Web app vulnerability Allows remote script execution
A form of code injection
Can vary in impact

3. Different XSS Persistent Reflected Stored by the server
Runs whenever the page is loaded
Can be coupled with viruses/worms
Usually more severe
Reflected
Much more common
Harder to leverage into deeper exploit
Usually visible in the URL

4. What this means to Network Security
XSS can be used to gain admin or user passwords or cookies which then could be used to upload viruses and whatnot
Compromise servers

6. Capabilities
The sky is the limit, or rather your imagination is the limit
XSS can be used in conjuncture with phishing, SQL and HTML injection, and/or viruses and worms.
Session jacking

8. Stored XSS Session Jacking

9. Time for a Demo!
<SCRIPT>alert(String.fromCharCode(88,83,83))</SCRIPT>
';alert(String.fromCharCode(88,83,83))//\';alert(String.fromCharCode(88,83,83))//";alert(String.fromCharCode(88,83,83))//\";alert(String.fromCharCode(88,83,83))//--></SCRIPT>">'><SCRIPT>alert(String.fromCharCode(88,83,83))</SCRIPT>

10. Time for a Demo! Example Example2
"><img+onerror="alert(String.fromCharCode(84,104,105,115,32,105,115,32,97,32,112,114,111,111,102,32,111,102,32,99,111,110,99,101,112,116,32,88,83,83,32,97,116,116,97,99,107,32,58,41))"+src="blah.png">

11. Prevention If this is so easy to do, how can I protect my site?
Stored functions – eliminate certain tags
Filters
Magic Quotes

12. Filtering Black Listing White Listing
Saying only alphanumeric and certain punctuations are allowed.
May annoy legitimate users who are trying, lets say, to use a contraction but the single quote is being blocked.
Blocking tags like <SCRIPT> or the alert function in javascript
This leaves open attacks that are disguised as images. (or whatever else the hacker may think of)

13. Circumventing filters
If say, the word “script” is filtered out, there are a few ways around this.
If it’s case sensitive then alternating camel case could get around it. Ex. sCrIpT
If they only filter the input once then placing the word inside itself. Ex. scrSCRIPTipt

14. Circumventing cont’
Convert to Unicode, hex, or salt the vector with vectors
Buffer Overflow (usually with A’s) with payload and vector attached to the end of your string
HTML entities. Ex. < , &

15. Sources OWASP Top 10 Vulnerabilities
The Web Application Hacker’s Handbook
Wikipedia
Zack Garcia