Dead or Alive? An Emotet Story

Back in May, The DFIR Report witnessed an intrusion that started from a phishing email which included Emotet.
The intrusion lasted four days and contained many of the usual suspects, including the Cobalt Strike post-exploitation framework.

The Emotet infection was delivered using a xls file containing a malicious macro, a technique that has been on the wane in recent months.
After executing the Emotet malware, it ran a few basic Windows discovery commands (systeminfo, ipconfig, etc.), wrote a registry run key for persistence, and made its initial call outs to the command and control servers.

Around 40 minutes after the initial execution, the Emotet malware started to run a new Emotet email spreader campaign.
This entailed connecting to various email servers and sending new emails with attached xls and zip files.
This activity continued until the UTC clock turned over to the next day; at which point, the email spreader halted for a period of time and around seven hours into the second day, it began running the email spreader again.

Around 26 hours after the initial infection, while still running the email spreader, the Emotet malware pulled down and executed a Cobalt Strike payload on the beachhead host.
Right after the beacon was executed, the threat actors began enumerating the network using native Windows binaries and the PowerView module, Invoke-ShareFinder.
Around 30 minutes after dropping the beacon the threat actor injected into a dllhost.exe process and then proceeded to dump credentials from LSASS.
Another 20 minutes later, the threat actor ran Invoke-ShareFinder again and Invoke-Kerberoast.

At 29 hours from initial access, the threat actors began their first lateral movement.
This was achieved by transferring a Cobalt Strike DLL over SMB and executing via a remote service on another workstation.
From there, they ran Invoke-Sharefinder once again, along with AdFind, using a batch file named find.bat.
Pass-the-Hash behavior was observed targeting several accounts on the lateral host.
Use of Cobalt Strike’s Get-System module was also apparent via the logs.

The threat actors then proceeded to do additional network discovery using a batch script named p.bat to ping all servers in the network.
More account discovery was then observed, with queries for Domain Administrators and a backup account.

At 31 hours into the intrusion, the threat actors pivoted to the Domain Controller using the same Cobalt Strike DLL.
Once on the Domain Controller, the threat actors again used Get-System to elevate and then dumped LSASS.
After completing that activity, the threat actors chose another server to push a file, 1.msi, to, which was the installation package for Atera-for an additional means of persistence and command and control.
During this whole second day, the original Emotet infection on the beachhead host was still trying to send more malicious emails, finally stopping for the day a little before 23:00 UTC.

They returned the next day, at the same time as the previous day, and picked up where they left off.
They pivoted to a couple of workstations on the network using Cobalt Strike and installed Atera and Splashtop with a different MSI installer.
Once again, they executed Invoke-Sharefinder, AdFind, and the p.bat batch script to ping online servers.
Using the remote admin tools, they used Rclone to exfiltrate important data from a file server and upload it to MEGA.
Interestingly, the threat actors exfiltrated the same data twice while running Rclone with the parameter -ignore-existing from two different hosts on the network.
Around 20:00 UTC the Emotet infection on the beachhead host began its email spreader activity again, only to halt at the change over at 00:00 UTC.

On the last day of this intrusion, the threat actors returned during their normal working hours and used Rclone to exfiltrate IT-related data from a separate server.
This was the last activity observed from this group.
These cases commonly end up with ransomware in addition to data exfiltration.
This, however, was not the case with this intrusion as the threat actors were evicted before any final actions could be taken.

Sign Up For Threat Alerts

Loading...
Threats Icon

Feb 06, 2023

Vector Stealer Targets RDP Files For Exfiltration

Vector Stealer is an information stealer sold on underground forums since 2022. The malicious software...

Threats Icon

Feb 05, 2023

Operation Ice Breaker

This is a new threat actor,Analysts are tracking it as Ice Breaker APT. Although research...

Threats Icon

Feb 05, 2023

Operation Ice Breaker

ttt

Threats Icon

Feb 05, 2023

Trigona Ransomware Analysis

Trigona ransomware appeared on the threat landscape in late 2022 and threatens to release stolen...

Threats Icon

Feb 02, 2023

Ukraine CERT-UA: Compromised Email Address Used To...

An adversary was discovered using a compromised e-mail address to send phishing emails with a...

Threats Icon

Feb 01, 2023

Ukraine Government Sector Targeted With The DolphinCape...

The government sector of Ukraine was targeted with spear-phishing emails with a malicious attachment which...

Threats Icon

Feb 01, 2023

Ukraine Government Sector Targeted With The DolphinCape...

The government sector of Ukraine was targeted with spear-phishing emails with a malicious attachment which...

Threats Icon

Jan 31, 2023

Multiple Malware Variants Distributed Through Microsoft OneNote

Spear-phishing emails with malicious Microsoft OneNote attachments were discovered delivering variants from the AsyncRAT, Formbook¸...

Threats Icon

Jan 30, 2023

Playing Whack-a-Mole With New Dharma Ransomware Variants

The Dharma ransomware family was initially identified in 2016 and operates as a Ransomware-as-a-Service (RaaS)...

Threats Icon

Jan 29, 2023

APT15 Targets Multiple Sectors With Turian Backdoor

APT15, also known as Playful Taurus, is an advanced persistent threat (APT) that conducts a...

Threats Icon

Jan 26, 2023

Vice Society Ransomware Group Targets Manufacturing Companies

The Vice Society threat group was discovered targeting multiple sectors including manufacturing companies in Brazil....

Threats Icon

Jan 26, 2023

US Cert Alert – Alert (AA23-025A) Protecting...

Although this campaign appears financially motivated, the authoring organizations assess it could lead to additional...

Threats Icon

Jan 25, 2023

Emotet Malware Makes a Comeback with New...

The Emotet malware operation has continued to refine its tactics in an effort to fly...

Threats Icon

Jan 25, 2023

DragonSpark

The DragonSpark attacks represent the first concrete malicious activity where Analysts observe the consistent use...

Threats Icon

Jan 25, 2023

PLAY Ransomware

PLAY is simple but heavily obfuscated with a lot of unique tricks that have not...