Kaspersky detects HOSTS as: Trojan.Win32.Hosts2.gen
Update: Kaspersky has corrected the issue with a new revision update ... however it appears a reboot is required.
Here we go again ... the folks over at Kaspersky in their latest update (03-14-2013) have added something that detects all custom HOSTS files as "Trojan.Win32.Hosts2.gen" (gen = generic). Hopefully they will reissue another update to fix this false-positive.
If you read thru a post in their Forum you will see that not only the MVPS HOSTS is detected ... but quite a few other recourses as well.
I do not use Kaspersky ... however a possible work-around until Kaspersky solves the problem:
Settings --> Threats & Exclusions --> Exclusions --> Settings --> Add --> Select file or Folder --> C:\Windows\System32\drivers\etc\
Folks as I've said before ... anytime after running a scan of any security related product and the only detection is one or more entries in the HOSTS file, this is most likely a false-positive and should be ignored, or excluded from future scans.
There is no known infection that only affects the HOSTS file!