Backdoor.Win32.POWRUN.AA.tmsr

 Analysis by: John Rey Canon

 ALIASES:

Backdoor.PowerShell.Agent.ao (Kaspersky); W32/PowerShell_Agent.AO!tr.bdr (Fortinet)

 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


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.

  TECHNICAL DETAILS

File Size:

67,584 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

23 Nov 2018

Payload:

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.

This malware arrives via the following means:

Installation

This Backdoor drops the following files:

  • %Application Data%\Windows\Microsoft\StartUp\{Random Name}.reg
  • %Application Data%\Windows\Microsoft\StartUp\{Random Name}.cmd'
  • %Application Data%\Windows\Microsoft\StartUp\{Random Name}.prc'
  • %Application Data%\Windows\Microsoft\StartUp\{Random Name}.res

(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, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)

Information Theft

This Backdoor gathers the following data:

  • OS Name
  • OS Version
  • Domain Name
  • User Name
  • IP Address

Other Details

This Backdoor does the following:

  • It is capable of the following:
    • Upload a file to file hosting service
    • Download a file to file hosting service
    • Remove persistence
    • Exit Process
    • Execute command via Invoke Expression

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.670.02

FIRST VSAPI PATTERN DATE:

06 Dec 2018

VSAPI OPR PATTERN File:

14.671.00

VSAPI OPR PATTERN Date:

07 Dec 2018

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

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 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%\Windows\Microsoft\StartUp\{Random Name}.reg
  • %Application Data%\Windows\Microsoft\StartUp\{Random Name}.cmd'
  • %Application Data%\Windows\Microsoft\StartUp\{Random Name}.prc'
  • %Application Data%\Windows\Microsoft\StartUp\{Random Name}.res

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Backdoor.Win32.POWRUN.AA.tmsr. 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.

Step 6

Scan your computer with your Trend Micro product to clean files detected as Backdoor.Win32.POWRUN.AA.tmsr. 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:


Did this description help? Tell us how we did.