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Backdoor.Win32.FLAWEDAMMY.AB

March 27, 2019
 Analysis by: Arvin Roi Macaraeg
 ALIASES:

Trojan:Win32/Fuery.B!cl(Microsoft), Win32:DangerousSig [Trj](Avast)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • 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.

  TECHNICAL DETAILS

File Size:

668,400 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

19 Feb 2019

Payload:

Creates miscellaneous registry entries, 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 drops the following files:

  • %User Temp%\delselfandsvrremove.bat <- delete itself

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

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • klsdajkg23hyjugy2342

It terminates itself if it finds the following processes in the affected system's memory:

  • QHActivesDEFENSE.EXE
  • QHSAFETRAY.EXE
  • QHWATCHDOG.EXE
  • CMDAGENT.EXE
  • CIS.EXE
  • V3LITE.EXE
  • V3MAIN.EXE
  • V3SP.EXE
  • SPIDERAGENT.EXE
  • DWENGINE.EXE
  • DWARKDAEMON.EXE

Other System Modifications

This Backdoor adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services
netsxuid = {Victims ID}

Backdoor Routine

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

  • File Manager
  • Audio Chat
  • View Screen
  • RDP Session
  • Remote Control
  • Service (Install/Start/Stop/Remove)
  • Mouse (Display Settings)
  • Key logger
  • Disable desktop background
  • Disable desktop composition
  • Disable visual effects

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

  • {BLOCKED}.{BLOCKED}.128.15:80

Information Theft

This Backdoor gathers the following data:

  • ID
  • OS version
  • Admin Priveleges(User account control)
  • Users Credentials (User account name)
  • Computer Name
  • List Smart-Card Availability
  • Antivirus product names obtained via WMI query
  • Malware installed time

Other Details

This Backdoor does the following:

  • This Backdoor accepts the following parameters:
    • -service
  • This Backdoor tries to connect to the following local RDP-server:
    • {BLOCKED}.{BLOCKED}.0.1

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.826.05

FIRST VSAPI PATTERN DATE:

20 Feb 2019

VSAPI OPR PATTERN File:

14.827.00

VSAPI OPR PATTERN Date:

21 Feb 2019

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 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\SYSTEM\CurrentControlSet\services
    • netsxuid = {Victims ID}

Step 5

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.
  • %User Temp%\delselfandsvrremove.bat

Step 6

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