This one-weak-link-and-you're-hosed maxim is nowhere more obvious than in malware campaigns via email. Send a malware-containing message to a large set of employees, and at least one person, no matter how smart, will open the email and blindly follow every suggested command. I've been involved in dozens of antiphishing education tests over the years, and in every case, a fairly large number -- between 25 and 50 percent -- of employees can be phished out of their credentials in the first round. While the conversion rate (as we call it) drops with each successive round of sending another test to those who have passed the prior trial, there will always be some portion of users that responds to every phishing attack.
The more complex your staffing mix becomes, the harder it is to shore up your defenses. Some of the biggest hacks in recent years have come from exploited contractors. One of the most damaging hacks, on Target retail stores in 2013, came from an exploited HVAC contractor.
Sometimes attackers can go right after your most trusted protection. In one of the most sophisticated attacks ever, an advanced hacker group compromised long-lauded computer security company RSA, using an attack centered on several pieces of old, unpatched software. Then they sent a malicious spreadsheet file, which helped them break in.
Forensics revealed that the users would have been prompted with no fewer than five messages warning that the content they were about to open could be malicious. In every warning instance, they had to choose a nondefault answer to bypass the warning, and in every case they did. Once the attackers got in, they stole the digital secrets to RSA's much trusted SecureID key fob and used what they learned to exploit their ultimate targets, which included U.S. military giants Northrop Grumman and Lockheed-Martin. Even if you have your security down pat, attackers will exploit your business partners and use what they find against you.
Even if you're perfect at detecting and remediating vulnerabilities, all an attacker has to do is use vulnerability analysis tools to "fingerprint" each of your operating systems and applications exposed to the Internet, then wait until one of those software vendors releases a critical patch. No matter how great a company is at patching, they aren't likely to patch assets faster than the attacker can make use of tools available within hours of the announced vulnerability.
Hackers can change tactics on a dime
Defenders, by definition, are reactive, and in the computer world, this makes us that much slower than attackers. It takes IT and the security industry about two to three years to sufficiently address a new threat. Attackers will have moved on to new or slightly different attacks well before then.
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