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Emotet C2 and Spam Traffic Video

This video covers a life cycle of an Emotet infection, including initial infection, command-and-control traffic,
and spambot activity sending emails with malicious spreadsheet attachments to infect new victims.

The video was recorded in a Windows Sandbox in order to avoid accidentally infecting my Windows PC with malware.

Initial Infection

Palo Alto’s Unit 42 sent out a
tweet with screenshots and IOCs from an Emotet infection in early March.
A follow-up tweet by Brad Duncan linked to a PCAP file containing
network traffic from the infection on Malware-Traffic-Analysis.net.

Claroty

Screenshot of original infection email from Unit 42


Image: Screenshot of original infection email from Unit 42

  • Attachment MD5: 825e8ea8a9936eb9459344b941df741a

Emotet Download

The PCAP from Malware-Traffic-Analysis.net shows that the Excel spreadsheet attachment caused the download of a DLL file
classified as Emotet.

CapLoader download of Emotet DLL from diacrestgroup.com

Image: CapLoader transcript of Emotet download

  • DNS: diacrestgroup.com
  • MD5: 99f59e6f3fa993ba594a3d7077cc884d

Emotet Command-and-Control

Just seconds after the Emotet DLL download completes the victim machine starts
communicating with an IP address
classified as a botnet command-and-control server.

Emotet C2 sessions with JA3 51c64c77e60f3980eea90869b68c58a8 in CapLoader

Image: Emotet C2 sessions in CapLoader

  • C2 IP: 209.15.236.39
  • C2 IP: 147.139.134.226
  • C2 IP: 134.209.156.68
  • JA3: 51c64c77e60f3980eea90869b68c58a8
  • JA3S: ec74a5c51106f0419184d0dd08fb05bc
  • JA3S: fd4bc6cea4877646ccd62f0792ec0b62

Emotet Spambot

The victim PC eventually started sending out spam emails.
The spam bot used TLS encryption when possible, either through SMTPS (implicit TLS) or with help of STARTTLS (explicit TLS).

Emotet spambot JA3 hash 37cdab6ff1bd1c195bacb776c5213bf2 in NetworkMiner Professional

Image: Emotet spambot JA3 hash in NetworkMiner Professional

  • SMTPS JA3: 37cdab6ff1bd1c195bacb776c5213bf2
  • STARTTLS JA3: 37cdab6ff1bd1c195bacb776c5213bf2

Transmitted Spam

Below is a spam email sent from the victim PC without TLS encryption.
The attached zip file contains a malicious Excel spreadsheet,
which is designed to infect new victims with Emotet.

Emotet spam email from PCAP

Image: Spam email extracted from Emotet PCAP with NetworkMiner

  • .zip Attachment MD5: 5df1c719f5458035f6be2a071ea831db
  • .xlsm Attachment MD5: 79cb3df6c0b7ed6431db76f990c68b5b

Network Forensics Training

If you want to learn additional techniques for analyzing network traffic, then take a look at our upcoming
network forensic trainings.

*** This is a Security Bloggers Network syndicated blog from NETRESEC Network Security Blog authored by Erik Hjelmvik. Read the original post at: https://www.netresec.com/?page=Blog&month=2022-05&post=Emotet-C2-and-Spam-Traffic-Video