Cybercriminals aren’t going to exert more effort than they have to. For all the talk of the sophisticated investment required to discover and exploit vulnerabilities to obtain a foothold into a targeted environment, email remains a perfectly welcoming – and far more time- and cost-effective – medium.
The payoff is simply too good for cybercriminals. Of course, that doesn’t mean attackers aren’t shifting tactics or developing innovative ways to take advantage of this low-hanging fruit and stay one step ahead of the defenders.
As always, knowledge is power when it comes to combatting the latest cyberthreats. Here is what Trustwave SpiderLabs incident investigators are seeing in the world of email.
1) Sextortion Messages
There is a rise in email-based blackmail, in which malicious senders attempt to trick users into believing that an attacker has obtained embarrassing information about them visiting pornographic websites and has collected pictures and audio from a hacked webcam. The sender threatens to release the allegedly compromising content to everyone in the victim’s contact/friend list or upload to their social media profile unless a payment is made (usually in cryptocurrency). For additional reading on this particularly terrifying threat, our Fahim Abbasi covered produced two blog posts.
2) IoT Botnets Delivering Spam
A collection of compromised IoT devices can form a formidable botnet (as was evident when Mirai arrived on the scene in late 2016) and the susceptibility and sheer growth of connected smart devices is providing a conducive pathway for more to emerge. Most of the action we have observed has been because of home routers, which failed to undergo proper patching as these devices rarely receive any kind of support after their release. Many of 2018’s biggest botnets used 5- or even 8-year-old vulnerabilities in router/modem firmware. These include Pitou, Type52 and Xinbot
3) A New Host Nation
Brazil has risen as a new source of phishing and banking attacks. Campaigns from this country were mainly targeting Latin American financial institutions, but customers from other regions, predominantly North America and EMEA, were affected as well.
4) File Extensions
As more users are trained to recognize tell-tale signs of phishing and spam, such as misspellings, grammatical errors and language issues, well-crafted messages greatly increase attack success rates, as do the usage of popular file types, a common way for malicious actors to mimic third-party communication and avoid detection by traditional email security. Most attachments used in malicious email files continue to be file formats related to message visual aspects (.gif .js) and MS Office documents (.xls and .doc) with malicious macros.
5) Emotet
This banking Trojan obtains financial information by injecting computer code into the networking stack of an infected computer, allowing sensitive data to be stolen via transmission. Emotet is often concealed in documents delivered through emails that pretend to be from financial institutions. The emails came with a Word document embedded with malicious macro code. Once executed, the code downloads and runs Emotet. The malware is not the final payload, though, as it acts as a downloader for additional malicious code.
6) Supply Chains
Attackers are increasingly use the supply chain in their email evil-doing, utilizing legitimate business partners – which are the victim of an initial attack – to distribute phishing/spam emails by using compromised legitimate addresses. Most of these third-party companies are unaware that they were spreading malware to all their business contacts. This approach increases ingress success rates for attackers by adding a “trusted” source of communication.
Dan Kaplan is manager of online content at Trustwave. Trustwave Cyber Threat Analyst Jakub Adamczyk contributed to this post.
