Last year, our threat researchers highlighted the Emotet malspam campaign which sent out unwanted gifts to email inboxes. The emails appeared to be sending recipients a holiday gift card — but instead, they included links that would download malicious word documents.
A year later, the Emotet malspam trojan remains one of the most active malware families. Development has continued on the malware with new features and modules still being added.
What is Emotet malspam trojan?
Emotet is a trojan that is typically spread through spam emails. The trojan module is capable of loading and installing additional malware, stealing online credentials and personal sensitive information. The bypass component enumerates network resources looking for servers — for each one it finds, it will try to bruteforce the administrator and user accounts. This lets the malware spread via default admin shares and shared folders using SMB to establish persistence. Additional data gathering capabilities include, but are not limited to, email exfiltration, collecting sender and destination names from the interpersonal message (IPM) root folder, harvesting emails that have been sent or received within the last 180 days. This method of harvesting data en-mass allows for a weaponized and data-driven analytical capability that increases the effectiveness and spread of the Emotet trojan. We observed the following secondary payloads: TrickBot, IcedID, QuakBot, AzoRult, Ursnif/Gootkit, and Zeus Panda Banker Trojans.
How can Cisco Umbrella help?
Malspam campaigns are highly automated and able to generate up to 500 weaponized documents hosted on compromised domains daily. Our internal security research team developed a Malspam classifier to automatically block Malspam campaigns. These blocks of the compromised domains hosting weaponized documents are derived from multiple sources including open-source intelligence (OSINT), infrastructure telemetry hunting algorithms, partner relationships and Umbrella’s research on co-occurrences and related domain models. Intelligence typically includes indicators gathered from malware, IPs, domains, campaign research and threat actor developments. When Emotet is detected, Cisco Umbrella will block at the IP and domain level, as well as analyze risky domains using a selective proxy.
How we gather threat intelligence for Cisco Umbrella
There are three key factors that make up our unparalleled threat intelligence: data, security researchers, and statistical and machine learning models. Umbrella resolves over 175 billion DNS requests daily, far more than any other security vendor, giving our researchers a unique view of the internet. This view allows us to quickly and effectively identify threat trends. Our industry renowned researchers are constantly finding new ways to uncover fingerprints that attackers leave behind by building new statistical and machine learning models. These models automatically classify our massive amounts of data.