only way a properly configured Windows machine can ever be infected by
viruses or malware, namely, a zero-day attack?
Unfortunately, zero-day attacks can be more like zero week/month
attacks.
Most of the systems I've had to clean in the last few months have
had variations of the 2010-antivirus trojan, installed using
drive by downloads due to problems with Internet Explorer.
That's why the German government advised people to stop using it.
http://mashable.com/2010/01/15/german-government-stop-using-internet-explorer/
While that particular problem has since been patched, given the
history of IE, I'm sure it won't be the last.
At least it enabled me to convince those people to only use admin
accounts, when they want to install programs, and/or updates, and
to stop using IE.
The only problem now is getting them to remember to login to the
admin account, at least once a week, to check for, and install
third party updates.
These were on systems using up-to-date av/m$ software. So the
problem does still exist, but is mostly rootkits and trojans,
rather then true viruses.
Part of the problem with m$ software, in general, is brain dead
decisions, that compromise security, to supposedly make the
system easier to use. Thinks like having known software
extensions, like .exe hidden by default. I don't see how that
makes it easier to use, but sure do see how it makes it less
secure. Making the admin account, the default for new systems
is just asking for newbie users, to get into trouble.
Another case I saw last fall, the user had purchased a system
with norton antivirus installed, set to auto-update. When the
user obtained a cable connection, they instructed her to install
there freely download mcafee av. Somehow she managed to get it
partially installed, with the result that neither was working.
That one had been turned into a spambot, with multiple back door
trojans, and root kits, which required full format and reinstall,
to clear up. She only had two online accounts, both used for
email, which were compromised. Luckily she wasn't using online
banking.
Regards, Dave Hodgins