Around three million Steam codes for Codemasters' DiRT 3 have been taken from a webserver operated by AMD, MCV reports.

The publisher and hardware manufacturer teamed up in a promotion giving buyers of an AMD graphics card a free copy of DiRT 3. However, it seems the codes for the promo weren't stored in a secure location.

Over the past few days the exposed codes have been passed around the internet giving a free copy of the hit racer to anyone who wanted one.

However, there may be some way for Codemasters and AMD to recover the situation, with any used codes likely to be relatively easy to track down via Steam.