After discussing the recent Yahoo DOM XSS with Shahin from Abysssec.com, it was discovered that Yahoo’s fix is not effective as one would hope. According to Yahoo, this issue was fixed at 6:20 PM EST, Jan 7th, 2013. With little modification to the original proof of concept code written by Abysssec, it is still possible to exploit the original Yahoo vulnerability, allowing an attacker to completely take over a victim’s account. The victim has to be lured to click a link which contains malicious XSS code for the attack to succeed. This can demonstrated by the video we have created just this morning (Jan 8th, 2013) after Shahin kindly shared proof of concept code with us.