Brian Krebs 23 November 2012 (krebsonsecurity)
A zero-day vulnerability in yahoo.com that lets attackers hijack Yahoo! email accounts and redirect users to malicious Web sites offers a fascinating glimpse into the underground market for large-scale exploits.
The exploit, being sold for $700 by an Egyptian hacker on an exclusive cybercrime forum, targets a “cross-site scripting” (XSS) weakness in yahoo.com that lets attackers steal cookies from Yahoo! Webmail users. Such a flaw would let attackers send or read email from the victim’s account. In a typical XSS attack, an attacker sends a malicious link to an unsuspecting user; if the user clicks the link, the script is executed, and can access cookies, session tokens or other sensitive information retained by the browser and used with that site. These scripts can even rewrite the content of the HTML page.
The hacker posted the following video to demonstrate the exploit for potential buyers. I’ve reproduced it and published it to youtube.
“I’m selling Yahoo stored xss that steal Yahoo emails cookies and works on ALL browsers,” wrote the vendor of this exploit, using the hacker handle ‘TheHell.’ “And you don’t need to bypass IE or Chrome xss filter as it do that itself because it’s stored xss. Prices around for such exploit is $1,100 – $1,500, while I offer it here for $700. Will sell only to trusted people cuz I don’t want it to be patched soon!"KrebsOnSecurity.com alerted Yahoo! to the vulnerability
, and the company says it is responding to the issue. Ramses Martinez, director of security at Yahoo!, said the challenge now is working out the exact yahoo.com URL that triggers the exploit, which is difficult to discern from watching the video.https://www.youtube.com/watch?feature=player_embedded&v=iBXvebXo-F4#