Last month, I told you about a colleague who had to deal with an outbreak of the ransomware known as "Locky." We found out that that infection happened when an employee foolishly opened a macro-enabled Microsoft Word document attached to a phishing email. The Word document, which contained Visual Basic code that delivered the malware, came in a phishing scam about an unpaid invoice. More details were purportedly included in the attached Word doc. Because such weaponized documents are a growing threat, I recommend that you block macro-enabled Office files from being delivered through email.
I’m concerned about the increasing level of sophistication of this type of phishing scam. In the past, we taught our employees to watch out for spelling errors, poor formatting, grammatical mistakes, janky graphics and other obvious clues to spot a fake. These days, phishing scams are not only slick and professional-looking, but also well thought out and tailored to their audience. They are much harder for the average user to immediately recognize as malicious, especially when they contain content relevant to the employee’s job (such as a fake invoice sent to the Accounts Payable department) or when they contain something irresistible to human nature (such as a list of top executives’ salaries and bonuses).
Over 75% of all emails coming into my company from the Internet are spam. I have two layers of spam filtering — one to filter out the majority of the obviously bad stuff, and another for more fine-grained sifting of the rest. Still, some get through. No spam filter is 100% perfect at distinguishing between real and fake emails. In fact, I err on the side of not delivering legitimate emails versus loosening up my filtering parameters (which has been a very unpopular decision — people get “email rage” when legitimate emails get quarantined in the system).
But because I’ve been seeing this increasing sophistication in the phishing emails coming into my company — and more of them slipping through our spam filters precisely because they are so official-looking — I’ve focused my attention on alerting our employees and teaching them how to detect the signs of phishing in this new threat landscape. Much of the old advice is no longer very helpful. What is still true, though, is that harmful messages usually carry a sense of urgency (open NOW!) and a threat of consequences (or you’ll be FINED!), and they come from an unexpected sender. But I’m also teaching my employees about relevance (are you the appropriate person to receive the email) and situational awareness (does the email make sense, is it expected, is it appropriate). These are more abstract concepts, and harder to teach. I believe it is paying off, however, and I believe it is part of the reason we’ve been able to go 90 days without an incident.
I never thought I’d long for the days of 419 scams and similar amateurish spam. But I have the uncanny sense today that there are real adversaries on the other end of the email pipeline who are smart and clever and have focused their attention on my company’s employees. And they’re not going away.
This week's journal is written by a real security manager, "J.F. Rice," whose name and employer have been disguised for obvious reasons. Contact him at jf.rice@engineer.com.
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