WORM_OTRAN.VTN

 Analysis by: Cris Nowell Pantanilla

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Propagates via flashdrives

This Worm arrives via removable drives.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

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

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size:

140,955 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

10 Jul 2017

Payload:

Downloads files

Arrival Details

This Worm arrives via removable drives.

Installation

This Worm drops the following files:

  • %System%\db.dll ← configuration file

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

It drops and executes the following files:

  • %System%\send.vbs ← connects to remote site

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

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

  • %System%\tcpip.exe
  • {malware path}\MyPicture.exe

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

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe tcpip.exe"

Propagation

This Worm searches for folders in all physical and removable drives then drops copies of itself inside the folder as {folder name}.EXE.

It drops the following copy(ies) of itself in all removable drives:

  • {Drive:}\driver.exe

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

[autorun]
open=driver.exe

Download Routine

This Worm accesses the following websites to download files:

  • http://www.{BLOCKED}iab.150m.com/update/updates{day now}.txt

It saves the files it downloads using the following names:

  • updates{day now}.vbs

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

Information Theft

This Worm gathers the following data:

  • Username
  • IP address

Other Details

This Worm connects to the following website to send and receive information:

  • http://{BLOCKED}tor.zoho.com/abc2008/data/form-embed/Datas/zhDk9rmCNd3E98p91y9ebdrjPyS1gQFe8zzwFYstwOVWGjGqMBq6xWbZFNpk71tUbvgagt1fWh12hYar1HR4zF1O7rFdqBb5QNPa
  • https://{BLOCKED}tor.zoho.com/abc2008/data/form-embed/Datas/zhDk9rmCNd3E98p91y9ebdrjPyS1gQFe8zzwFYstwOVWGjGqMBq6xWbZFNpk71tUbvgagt1fWh12hYar1HR4zF1O7rFdqBb5QNPa
  • http://{BLOCKED}m.zoho.com/crm/login.sas

It does the following:

  • It moves the original file "taskmgr.exe" to the following path:
    • %System Root%\taskmrg.exe ← original task manager

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

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.524.07

FIRST VSAPI PATTERN DATE:

10 Jul 2017

VSAPI OPR PATTERN File:

13.525.00

VSAPI OPR PATTERN Date:

11 Jul 2017

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

Identify and terminate files detected as WORM_OTRAN.VTN

[ 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 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • Shell = "Explorer.exe tcpip.exe"

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.
%System%\send.vbs
%System%\db.dll

Step 5

Search and delete AUTORUN.INF files created by WORM_OTRAN.VTN that contain these strings

[ Learn More ]
[autorun]
open=driver.exe

Step 6

Scan your computer with your Trend Micro product to delete files detected as WORM_OTRAN.VTN. 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 this Knowledge Base page for more information.


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