Over a quarter (29%) of threats spotted in Q4 2020 had never before been detected in-the-wild, giving attackers an advantage over their victims, according to HP Inc.
The tech giant’s latest Quarterly Threat Insights Report was compiled from data gathered from its global customers’ Sure Click virtual machines from October to December 2020.
While these isolated micro-VMs effectively segment malware from the endpoint and let it execute harmlessly, the widespread use of packers and obfuscation techniques would help malicious code bypass traditional detection-based filters, HP claimed.
Some 88% of threats were delivered via email, and it took nearly nine days on average for AV engines to recognize their hash. Fake invoice attachments were the most common lure.
Trojans accounted for 66% of malware in the period, driven by spam campaigns delivering banking malware Dridex.
Malicious executables surged by 12%, with CVE-2017-11882 accounting for nearly three-quarters of detections. Another legacy bug, CVE-2017-0199, accounted for a 12% growth in malware designed to run malicious scripts when a victim opens an Office document.
The two findings are a reminder that, despite the current focus on attacks exploiting zero-day vulnerabilities, many campaigns look to capitalize on the fact that organizations often overlook flaws left unpatched from years ago.
Other trends spotted by HP include email thread-hijacking designed to distribute Emotet in government organizations in Central America, the return of the ZLoader banking Trojan and a new Office malware builder (APOMacroSploit) used to craft delivery themed spam campaigns to distribute BitRAT malware.
“Opportunistic cybercrime does not show any signs of slowing. Low-cost malware-as-a-service kits are an attractive prospect to cyber-criminals and we have seen these continue to proliferate in underground forums. Kits like APOMacroSploit, which emerged in Q4 2020, can be bought for as little as $50 USD,” said Alex Holland, senior malware analyst at HP Inc.
“We have also seen threat actors continue to experiment with malware delivery techniques to improve their chances of establishing footholds into networks. The most effective execution techniques we saw in Q4 2020 involved old technologies like Excel 4.0 macros that often offer little visibility to detection tools.”