Analysis by: Jay Bradley Nebre
ALIASES:

Trojan:Win32/Skeeyah.A!bit(Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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 Type: JS
Memory Resident: Yes
Initial Samples Received Date: 12 Apr 2019
Payload: Connects to URLs/IPs

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.

Autostart Technique

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

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{6 random characters} = {download path}\{6 random characters}.{msi or exe}

Other Details

This Trojan does the following:

  • Places the downloaded file in either of the following paths
    • %User Startup%\
    • %User Profile%\Saved Games
    • %User Profile%\Contacts
    • %User Profile%\Links
    • %User Profile%\Music
  • Checks for the presence of any of the following files in it's download path
    • desktop.txt
    • desktop
    • desktop.ini
    • When found, run the following command "c:\\Windows\\System32\\cmd.exe /C start /MAX {URL of a legitimate site to fool targets}""
    • If not found, create the file and run the following command "c:\\Windows\\System32\\cmd.exe /C start /MAX {URL of a legitimate site to fool targets}"
  • Extracts the files from the downloaded zip file and renames it to the following names:
    • jesus/dump.exe/msi to {6 random characters}.exe/msi
    • jesus/dump.dmp to {6 random characters}.dmp
  • The malware then initiates system shutdown
  • Downloads a file from any of the following URLs:
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}tyhed6/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}aotk/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}orls/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}h5rtjyek796l78jrhrdhg65e/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}hrtyheujhsgrfdsg/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}audo/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}yeghfg/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}do/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}rzebrakkjsda/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}tyityh/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}ortosdfa/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}botsjd/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}5ysdgh/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}jr56t5ghrtdfggherhjd/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}6ygdfx/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}deadfikjg/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}as/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}tsdgsgbdt6jdfg/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}dalkj/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}iza/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}l86ol6i7rhtdsvfsfegd/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}do/image2.png
    • https://s3-eu-west-1.{BLOCKED}ws.com/{BLOCKED}ergeh54eghe5rye5hr56/image2.png

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.934.05
FIRST VSAPI PATTERN DATE: 12 Apr 2019
VSAPI OPR PATTERN File: 14.935.00
VSAPI OPR PATTERN Date: 13 Apr 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

Identify and terminate files detected as Trojan.JS.MSAIHA.SM

[ 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 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
    • {6 random characters} = {download path}\{6 random characters}.{msi or exe}

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.
  • {download path}\{drop filename}

Step 6

Scan your computer with your Trend Micro product to delete files detected as Trojan.JS.MSAIHA.SM. 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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