Infection Detections of Malware that Spread via AutoRun
Microsoft has admitted that malicious software are using AutoRun as a vector for infection, and thus newer versions of Windows (starting with 7) will not feature it for all removable media. Detachable hard drives, USB/thumb drives, rewritable CDs and DVDs and other “generic” mass storage devices will no longer use AutoRun by default. The idea is to reduce the chance of a machine getting infected by plugging in media you aren't sure of.
The commonly known AutoRun feature will be retained for read-only optical media, such as CDs and DVDs, claiming that those are seldom used as a transmission medium for malware or viruses. This may seem like a minor change, but it does represent a fundamental change in the way Microsoft developers are seeing security threats.