Trojan.Win32.MIRAI.MJZ

 Analysis by: Carl Maverick Pascual

 ALIASES:

Backdoor:Win32/Mirai.A (Microsoft) ; Trojan.Win32.Agentb.jagl (Kaspersky)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet


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.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size:

689,664 bytes

File Type:

EXE

File Compression:

Engima Protector

Memory Resident:

No

Initial Samples Received Date:

04 Feb 2019

Payload:

Connects to URLs/IPs, Downloads files

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:

  • %Windows%\System\msinfo.exe -> Detected as Trojan.Win32.SHELMA.AMC
  • %Windows%\System\upslist.txt -> Contains list of URL to download additional files with corresponding file name to save it.
  • %Windows%\System\my1.bat -> Contains several commands to be executed for initial machine infection

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

It adds the following processes:

  • cmd /c sc start xWinWpdSrv&ping 127.0.0.1 -n 10 && del

Other System Modifications

This Trojan modifies the following registry key(s)/entry(ies) as part of its installation routine:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\Tcpip\Parameters\
Interfaces
NameServer = 223.5.5.5,8.8.8.8

Download Routine

This Trojan connects to the following URL(s) to download its component file(s):

  • http://{BLOCKED}.{BLOCKED}.6.174/wpd.jpg
  • http://{BLOCKED}.{BLOCKED}.247.240/ok/ups.html
  • http://{BLOCKED}.{BLOCKED}.6.174/my1.html
  • http://{BLOCKED}.{BLOCKED}.6/174/update.txt

It saves the files it downloads using the following names:

  • http://{BLOCKED}.{BLOCKED}.6.174/update.txt -> %Windows%\System\upslist.txt
  • http://{BLOCKED}.{BLOCKED}.6.174/wpd.jpg -> %Windows%\System\msinfo.exe
  • http://{BLOCKED}.{BLOCKED}.6.174/my1.html -> %Windows%\System\my1.bat

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

Other Details

This Trojan does the following:

  • It does not proceed with its download routine if the machine is not a server.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.806.03

FIRST VSAPI PATTERN DATE:

11 Feb 2019

VSAPI OPR PATTERN File:

14.807.00

VSAPI OPR PATTERN Date:

12 Feb 2019

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 Trojan.Win32.MIRAI.MJZ

[ 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

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Tcpip\Parameters
    • From: NameServer = "223.5.5.5,8.8.8.8"
      To: NameServer = ""

Step 5

Search and delete these files

[ 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.
  • %Windows%\System\my1.bat
  • %Windows%\System\mysinfo.exe
  • %Windows%\System\upslist.txt

Step 6

Scan your computer with your Trend Micro product to delete files detected as Trojan.Win32.MIRAI.MJZ. 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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