The malicious Emotet botnet, which made a comeback in November 2021 after a 10-month break, is showing indications of steady expansion once again, collecting a colony of over 100,000 infected hosts to carry out its destructive actions.
In a new round of attacks, Emotet, a Banking Trojan which has evolved into a formidable modular threat, has reappeared with improved features. It has infected devices to carry out additional spam campaigns and install various payloads like the QakBot (Qbot) and Trickbot malware. These payloads would subsequently be utilized to give threat actors, such as Ryuk, Conti, ProLock, Egregor, and others, early access to deploy ransomware.
"While Emotet has not yet reached the same magnitude as before, the botnet is displaying a strong resurrection with a total of around 130,000 unique bots scattered over 179 countries since November 2021," Lumen's Black Lotus Labs researchers wrote in a report. On April 25th, 2021, German law enforcement used the network to send an Emotet module that removed the malware from afflicted devices.
The TrickBot malware has begun to dump an Emotet loader on affected devices, according to Emotet research group Cryptolaemus, GData, and Advanced Intel. While Emotet used to deploy TrickBot, the threat actors now use a mechanism called "Operation Reacharound" by the Cryptolaemus group, which rebuilds the botnet utilizing TrickBot's current infrastructure.
Apart from command-and-control (C2) lists and RSA keys, which change from version to version, Emotet's main payload hasn't changed much, but the list of phrases used to establish a process name for its bot has been renewed. Along with new binaries, words like engine, finish, magnify, resapi, query, skip, and many more are utilized and modified. Researchers may be able to construct signatures to detect Emotet infections on machines once these lists have been secured, but signature-based detection is more challenging if the list changes.
Abuse.ch has published a list of the new Emotet botnet's command and control servers and strongly advises network administrators to ban the linked IP addresses. Another new feature is the ability to collect extra system information from compromised workstations in addition to a list of running processes. The number of bots and associated dispersion are crucial indicators of Emotet's success in reconstructing its once-vast infrastructure.
