In the past, viruses and computer threats were created simply for the sake of it. Sometimes these threats would wipe your hard drive clean—just to let you know you’d been owned. This is not the case anymore; nowadays most of the threats we see are profit-oriented and try to keep a very low profile so that they aren't easily detectable by security software.
You can read the rest of this Blog here: Tidserv and M.S.10-015.