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Worm.JS.VJWORM.AK

January 02, 2020
 Analysis by: Clive Fuentebella
 ALIASES:

Trojan.Script (Ikarus), VBS/Downldr.LK (FPROT)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Via physical/removable drives, Downloaded from the Internet


This Worm arrives via removable drives. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It drops copies of itself in all removable drives.

It executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size:

56,832 bytes

Memory Resident:

Yes

Initial Samples Received Date:

21 Oct 2019

Payload:

Connects to URLs/IPs, Steals information

Arrival Details

This Worm arrives via removable drives.

It 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 Worm drops the following copies of itself into the affected system:

  • %Application Data%\{Script Filename}

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Other System Modifications

This Worm adds the following registry entries:

HKEY_CURRENT_USER
vjw0rm = {TRUE|FALSE}

Propagation

This Worm drops copies of itself in all removable drives.

It creates shortcut files (.LNK) disguised as folders or files located on the affected drives pointing to the malware copy.

Backdoor Routine

This Worm executes the following commands from a remote malicious user:

  • "Cl" - Closes the script
  • "Sc" - Downloads and runs a file from the C&C server
  • "Ex" - Executes a command
  • "Rn" - Downloads and runs a script from the C&C server
  • "Up" - Updates the script
  • "Un" - Uninstalls the script
  • "RF" - Downloads and runs a file from the C&C server

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://{BLOCKED}.{BLOCKED}.225.116:2135

As of this writing, the said servers are currently inaccessible.

Information Theft

This Worm gathers the following data:

  • Computer name
  • Username
  • OS name
  • Installed AV products
  • Volume serial number

  SOLUTION

Minimum Scan Engine:

9.850

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

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
    • vjw0rm = {TRUE|FALSE}

Step 4

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.
  • %Application Data%\{Script Name}
  • {Infected Drive}:\{Script Name}
  • {Infected Drive}:\{Original File/Subfolder}.lnk

Step 5

  1. Open a command prompt.
    • For Windows 7 users, click Start, enter CMD in the Find input field, and press Enter.
  2. In the CMD console, enter the following:

    ATTRIB [+R | -R] [+A | -A ] [+S | -S] [+H | -H] [+I | -I] [drive:][path][filename] [/S [/D] [/L]]

    Where:
    + Activates an attribute
    - Disables an attribute
    R Read-only file attribute
    A Archive file attribute
    S System file attribute
    H Hidden file attribute
    I Indexed file attribute without content
    [drive:][path][filename]
    Specifies one or more files in the current folder and all its subfolders
    /S Processes the corresponding files in the current folder and all its subfolders
    /D Process folders
    /L Act on the attributes of the symbolic link instrad of the target of the symbolic link
    Example:
    To make all files and folders (including subfolders visible in drive D:
    ATTRIB –H D:\* /S /D
  3. Repeat the step above for folders and files from other drives or directories.

Step 6

Remove malware/grayware files dropped/downloaded by Worm.JS.VJWORM.AK. (Note: Please skip this step if the threats listed below have already been removed.)

    Step 7

    Scan your computer with your Trend Micro product to delete files detected as Worm.JS.VJWORM.AK. 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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