Trojan:W32/Emotet

Behavior

Upon execution, Emotet will attempt to create a copy of itself and then delete the main executable.

Afterwards, it creates a child process of itself, which then creates a service and uses the Windows API CreateTimerQueueTimer to invoke a recurring thread which connects to a malicious command and control (C&C) server.

Infection Vector

Emotet is typically encountered when the user inadvertently opens a malicious file attachment that arrives via a spam email message.

Files Added

• Creates a copy of itself at "%WinDir%\System32|SysWOW64\[Dropped_Filename].exe" where "Dropped_Filename" is a combination of any of the following 2 strings (for example msicrypt.exe, ncbprovider.exe):
  

Registry Changes

Adds the following registry key to create service:

• HKLM\SYSTEM\ControlSet001\services\[Dropped_Filename]\Type:
  0x00000010
• HKLM\SYSTEM\ControlSet001\services\[Dropped_Filename]\Start:
  0x00000002
• HKLM\SYSTEM\ControlSet001\services\[Dropped_Filename]\ErrorControl:
  0x00000000
• HKLM\SYSTEM\ControlSet001\services\[Dropped_Filename]\ImagePath:
  "%windir%\System32|SysWOW64\[Dropped_Filename].exe"
• HKLM\SYSTEM\ControlSet001\services\[Dropped_Filename]\DisplayName:
  "[Dropped_Filename]"
• HKLM\SYSTEM\ControlSet001\services\[Dropped_Filename]\ObjectName:
  "LocalSystem"
• HKLM\SYSTEM\ControlSet001\services\[Dropped_Filename]\Description:
  "Copies and root certificates from smart cards into the current user’s certificate store, detects when a smart card is inserted into a smart card reader, and, if needed, installs the smart card Plug and Play minidriver."

Network Activity

It encrypts the following data using an RSA public key, which is present inside the file, then sends the encrypted data to the C&C server:

• Admin privilege + Computer Name and length of Computer Name + Hash of File-path of execution + Length and List of current process running

It connects to the following servers:

• 71.244.60[.]231:4143
• 84.200.208[.]98:80
• 91.217.66[.]130:443
• 193.169.54[.]12:8080
• 80.82.115[.]164:4143
• 186.103.199[.]252:4143
• 213.108.33[.]44:80
• 27.254.150[.]53:4143
• 189.51.144[.]3:80
• 159.203.94[.]198:4143
• 178.62.39[.]238:443
• 178.62.253[.]139:4143
• 52.4.64[.]240:4143

The following functionality may also be carried out if the C&C server responds:

• Download an upgraded version of Emotet
• Download and execute other malware
• Download module to spread itself in network

Analysis on file: 7e5e1f837189e5127aa86e0a834fe8f1e55c57c7

Analysis by: Neeraj Singh