Analysis by: Alyssa Christelle Ramos
ALIASES:

Generic.PwShell.Rozena.1.67B5F29E(BITDEFENDER)

 THREAT SUBTYPE:

Fileless

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • 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 executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 199,213 bytes
File Type: PS1
Memory Resident: Yes
Initial Samples Received Date: 01 Nov 2020
Payload: Connects to URLs/IPs, Steals information

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 injects codes into the following process(es):

  • powershell.exe

Backdoor Routine

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

  • Execute arbitrary commands
  • Manage Directory (Create, Set path, Remove)
  • List Drive Information
  • Manage Files (Modify, Open, Get file path, Copy, Move, Read/Modify file time)
  • Manage Services (Create, Delete, Start)
  • Manage Processes (Create, Terminate, List, Adjust permissions, Inject code)
  • Create pipe
  • Connect/Disconnect to a named pipe
  • Impersonate User Tokens
  • Retrieve IP Address mapping table
  • Enumerate Registry Data
  • Open Processes and obtain process information

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

  • http://{BLOCKED}rvicee.com/s/ref=nb_sb_noss_1/167-3294888-0262949/field-keywords=books

However, as of this writing, the said sites are inaccessible.

Information Theft

This Backdoor gathers the following data:

  • Host Name
  • Computer Name
  • User Name
  • OS Version and Architecture
  • Current Process ID

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 16.370.04
FIRST VSAPI PATTERN DATE: 24 Nov 2020
VSAPI OPR PATTERN File: 16.371.00
VSAPI OPR PATTERN Date: 25 Nov 2020

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 Backdoor.PS1.COBEACON.YXAK-B

[ 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

Scan your computer with your Trend Micro product to delete files detected as Backdoor.PS1.COBEACON.YXAK-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 the following Trend Micro Support pages for more information:


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