The answer is to check for a virus. Yeup you read right, your machine could be infected with the Flashback OSX Trojan. Won't happen to you? A good friend of FCP.co got hit.
Before Easter we read on numerous Apple news sites and blogs that up to 600,000 Macs had been infected by the Flashback OSX trojan. We always thought that you had to do something pretty stupid to get your Mac infected by a virus, so we didn't take much notice. Then Michele Yamazaki from Toolfarm posted that her computer had been a victim of the trojan and she assured us she hadn't been to any websites she shouldn't of!
"This is (sic) new Trojan Horse called Flashback. Last night my computer was acting up so I ran Disk First Aid, only to find that there was a strange mounted item that I did not have mounted - decryptedFile.dmg with the Adobe Flash Player installer. This is not really Adobe Flash Player Installer but a cleverly disguised virus."
So if it can happen to Michele it can happen to you, she knows her way around a Mac.
We immediately followed the advice given by F-Secure to discover via the Terminal if the trojan had installed any nasty malware on our growing collection of Macs. Luckily we got the all clear on every one.
As Macs become more popular and gain more market share then viruses are an unwelcome indicator of their popularity. Two points here. Firstly it will mean that Macs connected to the Internet will have to have more robust virus detection either from the OS or a third party. Secondly it's a good reminder that keeping an up to date backup isn't just to protect against a hard drive failure.