The recent OS X-specific Mac Trojan ignited many hot conversations on various security mailing lists last week. Supposedly, the excitement regarding the Trojan is that it is the first time profit-seeking criminals have paid attention to the OS X platform, versus script kiddies and the hobbyists. Personally, I don't know what the big deal is; Mac-based computers have been host to all the normal types of malware for more than two decades, albeit not as frequently as Microsoft Windows PCs.

Macs, PCs, and users

When I first started fighting malware writers more than 20 years ago, the only place you could find a PC virus was on a Mac. The first PC virus, Elk Cloner, was written for a Mac. Then DOS became more popular, so the virus writers started writing viruses for DOS. Next, Windows took over, and it's been the primary target of hackers ever since. Linux has its fair share of malware, and as OS X gains market share, malware writers are taking notice. I seriously doubt that the recent Trojan is the first malware attack against OS X by professional criminals.

The recent Mac Trojan waits for a user to visit a Web site promising, er, interesting video content. When the end-user visits the site, it prompts the user to download a needed QuickTime codec, which is really a Trojan program. If the user accepts the download and supplies their root password to install the bogus program, they get owned. The mail list conversations are all over the place, including the normal Mac-is-better-than-Windows-no-it's-not flame wars. How boring.

The one thread I found most interesting was whether or not malware that required end-user interaction and the root password could be counted as an exploit. Several very bright minds said something along the lines of, "If the computer is completely secure, but the end-user stupidly installs this obvious, malicious, crap piece of software, then it's the user's fault, not mine. It's not a security problem!"

Since I've documented that 86 percent of all (Windows) malware requires client-side interaction today, I'm not in that camp. Are we supposed to ignore the largest threat to our computer systems simply because our end-users disregard everything we tell them? Can I let my company get exploited over and over again, but tell my boss my hands are clean and I'm a success because I "secured" their computer systems?

The IM invasion

Most computer environments have an obligation to respond to threats that are caused by end-users unknowingly installing insecure software or using it in an insecure way. An example of this was when instant messaging began to take over the world. I personally didn't see the need or value of IM in my environment. "Heck, e-mail does everything IM can do, and with an audit trail," I said. But my opinion didn't matter.

One by one, end-users began to install instant messaging. I'd uninstall it on one user's workstation only to find it installed on the two PCs beside them. I was fighting a losing battle. I decided to block the IM network port to prevent the clients from connecting to the outside hosting channel servers, and the IM clients morphed to bypass the firewall settings. I went to complain to the company CEO, only to have him request that I install it on his computer. I didn't want to support IM, but eventually I learned that my job is not to decide what end-users or management should be running, but to secure as best as I can what they want to run.

The IM invasion (as I called it) was replaced with a p-to-p push, then music downloads (full of malware), and unauthorized USB keys ("Hey, what are those things?"). Then a major vendor, spending tens of millions of dollars on radio and magazine ads, convinced my end-users that they could not live without GoToMyPC. No need to get the IT staff involved. Firewalls are no problem. Right.