Sludge3000
A hacker has published code for potent cross-site scripting attacks that he claims go beyond the usual cookie stealing and phishing for users' private details.
Cross-site scripting (XSS) flaws allow attackers to present content under their control in the context of a vulnerable yet trusted site, thus tricking marks into handing sensitive information to miscreants. As well as creating a means to present pop-ups that link to a hacker-controlled site, XSSes can also lead to cookie theft.
Full story @ The Register
Proof of concept code and explanation