Original URL: http://www.theregister.co.uk/2011/03/11/xbox_promo_code_sploit/

XBox promo code exploit set Microsoft back $1.2m

Points make prizes

By John Leyden

Posted in Security, 11th March 2011 11:33 GMT

Hackers managed to figure out the algorithm used by Microsoft to generate promotional codes tied to XBox Live, costing Redmond an estimated $1.2m before it put a stop to the scam.

The algorithm created 160 counterfeit MS points, the currency used on XBox Live, at each iteration. "Hackers found an algorithm to add to existing, used codes to get new ones," reports gaming site Save and Quit.

There were two means towards exploiting the ruse. The first method involved repeatedly refreshing a website linked to code accumulation. However that route quickly became congested. The second method involved a trifle more skill and the use of counterfeit programs released on "gaming piracy" websites.

Save and Quit estimates that $1.2m was lost to the ruse before Redmond put a stop to it. Microsoft said losses were much lower without actually naming a figure.

Microsoft is reportedly in the process of identifying and cancelling points accrued through the ruse, which was only possible thanks to weak cryptographic security.

Meanwhile malware writers will doubtless jump onto publicity about the ruse to develop fake point-generator websites that lead only towards survey scams and supposed points-accumulation programs that are actually Trojans. Be careful out there. ®