Analysis by: Wilbert Luy
ALIASES:

Trojan:Win32/Azorult.B (Microsoft), HEUR:Trojan.Win32.Generic (Kaspersky)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan 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: 730,416 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 25 Jan 2019

Arrival Details

This Trojan 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 drops the following files:

  • %ProgramData%\localNETService\localNETService.exe
  • %Temp%\{random}.dat
  • %User Temp%\{random}.dat

(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit), or C:\Documents and Settings\All Users on Windows Server 2003(32-bit), 2000(32-bit) and XP.. %Temp% is the Windows temporary folder, where it usually is C:\Windows\Temp on all Windows operating system versions.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • %Program Files%\Google\Update\GoogleUpdate.exe /ua /installsource scheduler
  • %Program Files%\Google\Update\GoogleUpdate.exe /c

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Other System Modifications

This Trojan modifies the following file(s):

  • %Program Files%\Google\Update\GoogleUpdate.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\localNETService

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\localNETService

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\localNETService
Value_{5 random numbers} = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\localNETService
Type = "16"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\localNETService
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\localNETService
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\localNETService
ImagePath = "%ProgramData%\localNETService\localNETService.exe"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\localNETService
DisplayName = "localNETService"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\localNETService
ObjectName = LocalSystem

Other Details

This Trojan adds the following scheduled tasks:

  • Name:GoogleUpdateTaskMachineUA
    Action:%ProgramFiles%\Google\Update\GoogleUpdate.exe /ua /installsource scheduler
    Trigger:At 7:00 PM every day - After triggered, repeat every 1 hour for a duration of 1 day.
  • Name:GoogleUpdateTaskMachineCore
    Action:%ProgramFiles%\Google\Update\GoogleUpdate.exe /c
    Trigger:At log on of any user; At 7:00 PM every day

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.800.05
FIRST VSAPI PATTERN DATE: 08 Feb 2019
VSAPI OPR PATTERN File: 14.801.00
VSAPI OPR PATTERN Date: 09 Feb 2019

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 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

Deleting Scheduled Tasks

The following {Task Name} - {Task to be run} listed should be used in the steps identified below:

  • Name:GoogleUpdateTaskMachineCore
    Action:%ProgramFiles%\Google\Update\GoogleUpdate.exe /c
    Trigger:At log on of any user At 7:00 PM every day
  • Name:GoogleUpdateTaskMachineUA
    Action:%ProgramFiles%\Google\Update\GoogleUpdate.exe /ua /installsource scheduler
    Trigger:At 7:00 PM every day - After triggered, repeat every 1 hour for a duration of 1 day.

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Open the Windows Scheduled Tasks. Click Start>Programs>Accessories>
    System Tools>Scheduled Tasks.
  2. Locate each {Task Name} values listed above in the Name column.
  3. Right-click on the said file(s) with the aforementioned value.
  4. Click on Properties. In the Run field, check for the listed {Task to be run}.
  5. If the strings match the list above, delete the task.

For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:

  1. Open the Windows Task Scheduler. To do this:
    • On Windows Vista, Windows 7, and Windows Server 2008, click Start, type taskschd.msc in the Search input field, then press Enter.
    • On Windows 8, Windows 8.1, and Windows Server 2012, right-click on the lower left corner of the screen, click Run, type taskschd.msc, then press Enter.
  2. In the left panel, click Task Scheduler Library.
  3. In the upper-middle panel, locate each {Task Name} values listed above in the Name column.
  4. In the lower-middle panel, click the Actions tab. In the Details column, check for the {Task to be run} string.
  5. If the said string is found, delete the task.

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\ControlSet001\services
    • localNETService
  • In HKEY_LOCAL_MACHINE\SOFTWARE
    • localNETService

Step 5

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.
  • %User Temp%\{random}.dat
  • %ProgramData%\localNETService\localNETService.exe
  • %Temp%\{random}.dat

Step 6

Scan your computer with your Trend Micro product to delete files detected as Trojan.Win32.AZORUIT.A. 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:

Step 7

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %Program Files%\Google\Update\GoogleUpdate.exe


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