Because of a variety of obfuscation techniques and because defenders are often lax about looking for older threats, a lot of the viruses and malware coming out is not detected by the current versions of antivirus applications on the first day or few weeks, Corey Nachreiner, chief technology officer at WatchGuard, told eWEEK.
“It is really easy for the bad guys to make old malware look new again,” he said. “We are seeing plenty of old techniques being used in new malware, such as macro malware.”
Older techniques and malware have a habit of resurfacing occasionally. Reusing system utilities—the original version of computer hacking—is a tactic increasingly utilized by attackers attempting to maintain a low profile on compromised systems.
Worms and viruses with a network propagation mechanism have also occasionally reappeared. The Conficker virus has occasionally popped up. A year ago, for example, security firm Check Point Software Technologies revealed that Conficker made up 20 percent of the attacks recognized by its systems.
Microsoft SQL Slammer topped the threats seen by network-security firm Fortinet in Q4 2016. The company saw a surge in Slammer detections and SQL injection attacks in mid-to-late December. Much of the attacks came from universities in the U.S., which may have been attackers searching for legacy and vulnerable servers, according to Fortinet.
“They are still probing for old vulnerabilities and much of that is likely due to them being loaded into automated tools,” Derek Manky, global
security strategist for Fortinet, told eWEEK. “The effect, of course, is the same; you can’t assume vulnerabilities get so old that they fall off the attacker radar.”
Not all companies are seeing the uptick in Slammer attacks. WatchGuard saw no similar increase, the company’s Nachreiner said.
“We did not see it in our top-10 or the top-100,” he said.
The company did find that 30 percent of malware escaped detection by standard antivirus software. Calling this “zero-day malware,” the company said it showed that the use of obfuscation by attackers made known malware able to escape detection.