A lot of the discussion I see has revolved around whether the attack “qualifies” as an Advanced Persistent Threat, and therefore whether the term APT has any real meaning or is just some government conspiracy to scare us all into submission. After all, the critics say, it was just an email with an Excel spreadsheet. Nothing “advanced” there. Hardly the insidious espionage we’re all supposed to be worried about. APT defenders point out that the Flash exploit was sophisticated and therefore that makes it an APT, and we should be afraid – very afraid.
While its true that the term “Advanced Persistent Threat” has been used so much in the press and vendor advertisements that it seems to mean anything you want it to, this debate just clouds the real issue. The fact is that anyone can be fooled by a phishing attempt. The attacker’s goal is not to be “advanced,” their goal is to steal information. The reason the attackers use “simple” attacks is…they work most of the time. When they don’t, the attackers up their game and use more sophisticated ones. That’s the “persistent” part: if at first they don’t succeed, they will try, try again.
My point is that your front-line defenses – firewalls, antivirus, antispam, etc. will eventually fail. You cannot rely on there being no vulnerabilities in your software or your users never making mistakes. Your end users will be compromised at some point. It’s just a matter of time.
So, to effectively defend against attacks, you must be able to detect the compromise when (not if) it happens and respond effectively. That means building your network so it’s defensible in the first place. You need to compartmentalize your internal network to slow down attackers and get them to reveal themselves. You need to monitor your network activity so that you can detect unexpected activity. And finally, you need to respond effectively to contain and eradicate the attack.