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.
Niklas Femerstrand is the hacker who in October 2011 discovered that a debugging tool on the American Express website was vulnerable to an XSS flaw. He developed an “XSS on steroids” script while researching a similar flaw on the website of an unnamed Swedish bank.
“There are common myths about XSSes saying they can only be be used for phishing and cookie harvesting,” he said. “My code bursts those myths and is so the first way of transforming a ‘non persistent’ XSS into a persistent state.”