 Since this was in violation of the driver signing requirement, Microsoft closed this workaround with hotfix KB932596, by revoking the certificate with which the surrogate driver was signed.Security researchers Alexander Sotirov and Mark Dowd have developed a technique that bypasses many of the new memory-protection safeguards in Windows Vista, such as address space layout randomization (ASLR).The result of this is that any already existing buffer overflow bugs that, in Vista, were previously not exploitable due to such features, may now be exploitable.