TSPY_EMOTET.THHOAAH

 Analysis by: Carl Maverick Pascual

 ALIASES:

Trojan:Win32/Emotet.AC!bit (Microsoft) : Trojan-Ransom.Win32.Spora.ffa (Kaspersky)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan Spy

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Trojan Spy arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size:

131,584 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

31 Jul 2018

Arrival Details

This Trojan Spy arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Trojan Spy drops the following files:

  • %User Temp%\{temp file #1}.tmp
  • %User Temp%\{temp file #2}.tmp
  • %User Temp%\{temp file #3}.tmp

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.)

It drops and executes the following files:

  • %System%\{random file name}.exe -> Drops when file is run with admin rights
  • %AppDataLocal%\Microsoft\Windows\{random file name #1}.exe -> Drops when file is run without admin rights
  • %AppDataLocal%\Microsoft\Windows\{random file name #2}.exe -> deleted after execution

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local on Windows Vista, 7, and 8.)

It adds the following processes:

  • "%AppDataLocal%\Microsoft\Windows\{random file name}.exe" /scomma "%User Temp%\{temp file #3}.tmp"
  • "%AppDataLocal%\Microsoft\Windows\{random file name}.exe" "%User Temp%\{temp file #3}.tmp"
  • "%AppDataLocal%\Microsoft\Windows\{random file name}.exe" /scomma "%User Temp%\{temp file #2}.tmp"

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.)

Autostart Technique

This Trojan Spy adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random file name} = %AppDataLocal%\Microsoft\Windows\{random file name}.exe

It adds and runs the following services:

  • Service Name: {random file name}
    Service Description: Provides support for out-of-process session states for ASP.NET. If this service is stopped, out-of-process requests will not be processed. If this service is disabled, any services that explicitly depend on it will fail to start.
    InputPath: %System%\{random file name}.exe

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Other Details

This Trojan Spy connects to the following possibly malicious URL:

  • http://{BLOCKED}.{BLOCKED}.250.244:443/
  • http://{BLOCKED}.{BLOCKED}.74.233/
  • http://{BLOCKED}.{BLOCKED}.61.91/
  • http://{BLOCKED}.{BLOCKED}.124.249:443/
  • http://{BLOCKED}.{BLOCKED}.205.116:443/whoami.php
  • http://{BLOCKED}.{BLOCKED}.205.235/whoami.php

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.416.02

FIRST VSAPI PATTERN DATE:

01 Aug 2018

VSAPI OPR PATTERN File:

14.417.00

VSAPI OPR PATTERN Date:

02 Aug 2018

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Identify and terminate files detected as TSPY_EMOTET.THHOAAH

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services
    • {random file name}

Step 5

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {random file name} = "%AppDataLocal%\Microsoft\Windows\{random file name}.exe"

Step 6

Search and delete this file

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %System%\{random file name}.exe
  • %AppDataLocal%\Microsoft\Windows\{random file name}.exe

Step 7

Scan your computer with your Trend Micro product to delete files detected as TSPY_EMOTET.THHOAAH. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check the following Trend Micro Support pages for more information:


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