Backdoor.Win32.SPACECOLON.B

September 21, 2023
 Analysis by: John Rainier Navato
 ALIASES:

HEUR:Trojan-Banker.Win32.Delf.gen (KASPERSKY)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

This Backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It does not have any propagation routine.

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

  TECHNICAL DETAILS

File Size:

10,403,792 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

11 Sep 2023

Payload:

Connects to URLs/IPs, Executes commands

Arrival Details

This Backdoor 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 Backdoor drops the following files:

  • {Malware Path}\cdn.pfx → encrypted certificate
  • {Malware Path}\{Malware File Name}.ini → collected information

Propagation

This Backdoor does not have any propagation routine.

Backdoor Routine

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

  • CONNECT → used to connect to a C&C server
  • TUNNEL → used to establish tunnel connections between compromise machines
  • TUNNELCLOSE → used to disconnect the connection set up by the TUNNEL command
  • DOWNEXEC → used to download a file from a url that needs to be specified
  • USERADD → used to add a new administrator account with given username and password

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

  • https://www.{BLOCKED}ate.net/update.php
  • https://ss.{BLOCKED}8.org/update.php
  • https://update.{BLOCKED}u.net
  • https://update.{BLOCKED}2.org/update.php
  • https://{BLOCKED}cdnup.com/update.php
  • http://{BLOCKED}st/login/update.php

Rootkit Capabilities

This Backdoor does not have rootkit capabilities.

Other Details

This Backdoor adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\StorageDataServ

It does the following:

  • It must be executed with a specific execution parameter in order to continue to its behavior.
  • It creates the following service:
    • Service name = StorageDataServ
    • ImagePath = {Malware Path}\{Malware File Name}.exe /startedbyscm:00D244E7-B5119CE0-StorageDataServ
    • Description = Facilitates the running of interactive applications with additional administrative privileges. If this service is stopped, users will be unable to launch applications with the additional administrative privileges they may require to perform desired user tasks.
    • DisplayName = Data Share Service
  • It gathers the following information:
    • Computer Name
    • User Domain
    • OS information
    • Local IP Address
  • It creates the following scheduled task:
    • Name: Monitor Service Health
    • Trigger: Daily (After triggered, repeat every 1 hour indefinitely)
    • Action: cmd.exe /c net start "StorageDataServ"

It accepts the following parameters:

  • /install - create a service named "StorageDataServ"
  • /reinstall - recreate a service named "StorageDataServ"
  • /uninstall - stops and deletes a service named "StorageDataServ" if it exists.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

18.701.00

FIRST VSAPI PATTERN DATE:

16 Sep 2023

VSAPI OPR PATTERN File:

18.701.00

VSAPI OPR PATTERN Date:

17 Sep 2023

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

Restart in Safe Mode

[ Learn More ]

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\CurrentControlSet\services\StorageDataServ

Step 5

Deleting Scheduled Tasks while in Safe Mode

  1. Still in safe mode, the following {Task Name}-{Task to be run} listed should be used in the steps identified below:
    • Task Name: Monitor Service Health
    • Task to be run: cmd.exe /c net start StorageDataServ
  2. For Windows 7 and Server 2008 (R2) users, click Start>Computer.
    • For Windows 8, 8.1, 10, and Server 2012 users, right-click on the lower left corner of the screen, then click File Explorer.
  3. In the Search Computer/This PC input box, type:
    • %System%\Tasks\{Task Name}
  4. Once located, select the file then press SHIFT+DELETE to delete it.
  5. Open Registry Editor. To do this:
    • For Windows 7 and Server 2008 (R2) users, click the Start button, type regedit in the Search input field, and press Enter.
    • For Windows 8, 8.1, 10, and Server 2012 (R2) users, right-click on the lower left corner of the screen, click Run, type regedit in the text box
  6. In the left panel of the Registry Editor window, double-click the following:
    • HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Schedule>TaskCache>Tree>{Task Name}
  7. Locate the created entry and take note of the registry value's data:
    • ID={Task Data}
  8. After taking note of the data, delete the registry key:
    • HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Schedule>TaskCache>Tree>{Task Name}
  9. In the left panel of the Registry Editor window, double-click the following:
    • HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Schedule>TaskCache>Tasks
  10. Still in the left panel, locate and delete the registry key with the same name as the located Task Data in step #6:
    • ={Task Data}
  11. Close Registry Editor.

Step 6

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.  
  • {Malware Path}\cdn.pfx
  • {Malware Path}\{Malware File Name}.ini

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Backdoor.Win32.SPACECOLON.B. 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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