A Microsoft Security Essentials virus scan just finished on one of our computers and it shows two potential threats in Internet Explorer's temporary internet files:
The two items were downloaded on the same date about a year ago, so I think it's safe to assume a user visited a malicious site (item #1) which downloaded the PDF (item #2). The user account is an unprivileged non-administrative account.
According to Microsoft, the PDF was meant to exploit a bug in an old version of Adobe Reader which had been fixed long before the PDF was downloaded. We keep our software up-to-date here, so it looks like this exploit failed. The virus scan didn't detect any other problems.
My main concern is that the malicious site tried to use several exploits and Security Essentials didn't detect all of them. Should I nuke from orbit just in case, or trust the antivirus and let it just delete the files?