Mikko Hypponen of F-Secure attempts to explain why anti-virus companies didn’t catch Stuxnet, DuQu, and Flame:
When we went digging through our archive for related samples of malware, we were surprised to find that we already had samples of Flame, dating back to 2010 and 2011, that we were unaware we possessed. They had come through automated reporting mechanisms, but had never been flagged by the system as something we should examine closely. Researchers at other antivirus firms have found evidence that they received samples of the malware even earlier than this, indicating that the malware was older than 2010.
What this means is that all of us had missed detecting this malware for two years, or more. That’s a spectacular failure for our company, and for the antivirus industry in general.
It wasn’t the first time this has happened, either. Stuxnet went undetected for more than a year after it was unleashed in the wild, and was only discovered after an antivirus firm in Belarus was called in to look at machines in Iran that were having problems. When researchers dug back through their archives for anything similar to Stuxnet, they found that a zero-day exploit that was used in Stuxnet had been used before with another piece of malware, but had never been noticed at the time. A related malware called DuQu also went undetected by antivirus firms for over a year.
Stuxnet, Duqu and Flame are not normal, everyday malware, of course. All three of them were most likely developed by a Western intelligence agency as part of covert operations that weren’t meant to be discovered.
His conclusion is simply that the attackers—in this case, military intelligence agencies—are simply better than commercial-grade anti-virus programs.
The truth is, consumer-grade antivirus products can’t protect against targeted malware created by well-resourced nation-states with bulging budgets. They can protect you against run-of-the-mill malware: banking trojans, keystroke loggers and e-mail worms. But targeted attacks like these go to great lengths to avoid antivirus products on purpose. And the zero-day exploits used in these attacks are unknown to antivirus companies by definition. As far as we can tell, before releasing their malicious codes to attack victims, the attackers tested them against all of the relevant antivirus products on the market to make sure that the malware wouldn’t be detected. They have unlimited time to perfect their attacks. It’s not a fair war between the attackers and the defenders when the attackers have access to our weapons.
We really should have been able to do better. But we didn’t. We were out of our league, in our own game.
I don’t buy this. It isn’t just the military that tests its malware against commercial defense products; criminals do it, too. Virus and worm writers do it. Spam writers do it. This is the never-ending arms race between attacker and defender, and it’s been going on for decades. Probably the people who wrote Flame had a larger budget than a large-scale criminal organization, but their evasive techniques weren’t magically better. Note that F-Secure and others had samples of Flame; they just didn’t do anything about them.
I think the difference has more to do with the ways in which these military malware programs spread. That is, slowly and stealthily. It was never a priority to understand—and then write signatures to detect—the Flame samples because they were never considered a problem. Maybe they were classified as a one-off. Or as an anomaly. I don’t know, but it seems clear that conventional non-military malware writers who want to evade detection should adopt the propagation techniques of Flame, Stuxnet, and DuQu.
EDITED TO ADD (6/23): F-Secure responded. Unfortunately, it’s not a very substantive response. It’s a pity; I think there’s an interesting discussion to be had about why the anti-virus companies all missed Flame for so long.