Researchers at Microsoft have spotted a new variant of the Emotet Trojan, a threat used by cybercriminals to collect banking credentials.
The malware variant, detected by Microsoft as Trojan:Win32/Emotet.C, was first seen in November, when malicious actors were distributing it with the aid of spam emails related to phone bills and invoices.
The campaign, which peaked in November, mainly targeted German speakers. In the last 30 days, the largest number of victims were identified in Germany (44.33%), Austria (11.64%), and Switzerland (3.66%). Infections were also seen in Hungary, Poland, the Netherlands, Slovenia, the Czech Republic, Denmark and the Slovak Republic, Microsoft said.
The spam emails contain links that point to websites set up to serve a .zip archive containing an executable file. To avoid raising suspicion, the attackers use PDF document icons and long names that make the file extension more difficult to notice.
To ensure that their malicious messages get past spam filters, the cybercrooks rely on legitimate email accounts that have been hijacked.
“Emotet's spam module (detected as Spammer:Win32/Cetsiol.A) logs into email services using the stolen account name and passwords to send the spam. This means traditional anti-spam techniques, such as callback verification, won't be applicable because the email is sent from a vetted or legitimate email address,” HeungSoo (David) Kang of Microsoft’s Malware Protection Center wrote in a blog post on Tuesday.
Once it infects a device, Emotet monitors victims’ online activities and steals their credentials when they log in to their accounts on certain banking websites.The list of targeted organizations, which can be updated by the attackers at any time, includes Wells Fargo, Vodafone, Raiffeisen Bank, Bank1Saar, Berliner Bank, Flessa Bank, GE Capital, Sparda-Banken, Commerzbank, and Telekom.
A component of the malware detected as PWS:Win32/Emotet.E is capable of stealing usernames and passwords for email and instant messaging applications such as Yahoo! Messenger, Gmail Notifier, Google Talk, Group Mail, Thunderbird, Windows Live Messenger, Netscape, Outlook, Windows Mail, IncrediMail, and Google Desktop.
This information is sent back to a command and control (C&C) server, and is later used by the cybercriminals to send out spam emails carrying the threat from the compromised accounts.
Emotet was first spotted in June 2014 by Trend Micro. The banking malware caught the attention of researchers because it relies on network sniffing to harvest sensitive information from users. The Trojan injects itself into processes in order to monitor victims’ online activities and steal their information. The threat can also intercept data sent over secure connections by hooking various network APIs.