Suspicious.S.MrC

 Yesterday I sent a sample to SSR.  The answer was:

 

filename:  driver_detective_6.4.1.5_keygen.exe
machine: Machine
result: This file is detected as Suspicious.S.MrC.  Developer notes:
driver_detective_6.4.1.5_keygen.exe reserves one slot in Tier 1 for future malicious behavior category 

 

NIS 2009 with the latest virus definition  and heuristic set to aggressive tell me the  the file is clean.  Also, what does it mean "reserves one slot in Tier 1 for future malicious behavior category"