Even with the best preparation, a Trojan Horse virus can still get through your defenses.

Classic Trojan Horse

This happened to me the other day, even though I have virus protection installed on my computer.  Despite having up to date definition files, one got through and started causing my computer to act odd.  I knew something was wrong but didn’t know what it was at first.  The virus scan that I did with McAfee Security Center did not reveal anything.  However, when I went to run an online virus scan with Trend Micro, something blocked that from running.  Same thing happened when I went to download Ad-Aware from Lavasoft, so I knew there was malicious software on my computer.

The solution was to download Ad-Aware to my laptop and copy the file over using a USB thumbdrive.  I was able to install Ad-Aware then run a scan to find what was causing the problem.  Sure enough, the scan revealed that a trojan horse virus was in Thunderbird (Trojan.Agent.AUKO to be exact) which was immediately quarantined.  Later, I had Ad-Aware remove the threat so it would no longer be on my computer.

The lesson in all this is sometimes malicious software can sneak through your defenses.  Its wise to have backup means of detecting and removing software.  Having a second uninfected computer helps too if you have the resources to own one.  Being aware of the symptoms associated with an infection as well as knowing how to deal with them will lessen the impact of a trojan horse virus, spyware, worm, or other malware.  So learn from my experience and have backup plans in place for dealing with malicious computer software, you will be glad you did when this happens to you.