Mimecast Rejected Over 67 Billion Emails. Here's What It Learned

New research released today from Mimecast has found that the bad threat actors are modifying old exploits as well as changing their attack techniques in which they link to documents or landing pages on well-known cloud platforms using URLs that otherwise would appear to be legitimate.

The report, "Mimecast's Threat Intelligence Report, Black Hat Edition 2019," leverages the processing of some 160 billion emails during the period of April 2019 to June 2019. During this time, Mimecast rejected more than 67 billion of those emails and based its subsequent analysis on rejections classified as spam, opportunistic and targeted attacks, and impersonation detections.

"We have seen a marked increase in malware links," says Josh Douglas, Mimecast's vice president of threat intelligence. "We also found that nearly 30% of the impersonation attacks were targeted at the management and consulting sectors and biotechnology."

Peter Firstbrook, a research vice president who covers security at Gartner, says he doesn't worry too much about attachments and links. That's because most vendors are good at detecting them, and most organizations have endpoint protection and secure Web gateways that serve to backstop email security, he explains. However, he say he's very concerned about impersonation attacks, mainly business email compromises (BECs).

"The BEC-type attacks are the most interesting and difficult to detect," Firstbrook says. "There is no payload or URL to detect. It's typically just a person-to-person email from a legitimate account. Users trust email not knowing or understanding that email is not an authentication method. Companies are losing real money to these types of attacks, and few legacy solutions adequately protect them. Even newer solutions are still evolving their techniques to detect these threats."

Mimecast's Douglas says security managers should respond with the following: a layered security strategy, advanced targeted threat protection, and better user awareness training.

The Mimecast report also identifies professional education, which includes private educational companies, colleges, institutes, and training providers, as the most targeted industry. Mimecast believes this is because of higher education's inherent conflict with being open institutions of higher learning. Attackers prey on students who may not have the highest security awareness, plus numerous institutions conduct federal government research, so the attackers are after intellectual property and classified research.

Other highly targeted sectors include software and software-as-a-service (SaaS), which were hit with a number of attacks during this past quarter using Adwind and QRat. Similar to Adwind, QRat is a Trojan that targets Java-based platforms and uses Java Archive (.JAR) attachments in the malicious emails. IT resellers were also hit with a large number of Adwind attacks during the quarter, as well as a mixture of other Trojan downloaders.

The report also found Emotet to be another of the more active campaigns. What started as a banking Trojan in 2014 has evolved and now appears to download secondary malware. This may be because the threat actors behind Emotet have adapted it into a packing and delivery service for other threat actors, the report states, basically using it as a downloader-as-a-service for other malware.

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