Analysis by: Rheniel Rhay Ramos

ALIASES:

Packed.Win32.Dico.gen (Kaspersky); Spyware.LokiBot (Malwarebytes); Trojan:Win32/Pynamer.A!ac (Microsoft)

 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: Dropped by other malware, 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.

It creates folders where it drops its files.

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

  TECHNICAL DETAILS

File Size: 714,752 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 08 Feb 2018
Payload: Compromises system security, Connects to URLs/IPs, Drops files

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 copies of itself into the affected system and executes them:

  • %Application Data%\SubDir\Client.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

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

  • MUTEX_OBFbLxWIM8FvuSNev1

Autostart Technique

This Backdoor enables its automatic execution at every system startup by dropping the following copies of itself into the Windows Common Startup folder:

  • %User Startup%\scvhost.vbs -> used to execute {Malware path}\{Malware Name}.exe

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Backdoor Routine

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

  • Update Connection
  • Restart Connection
  • Disconnect Connection
  • Uninstall itself
  • View System Information
  • Open File Manager
  • Open Startup Manager
  • Open Task Manager
  • Open Remote Shell
  • Open TCP Connections (IPv4 and IPv6 support)
  • Reverse Proxy (SOCKS5)
  • Open Registry Editor
  • Elevate Client Permissions
  • Computer Commands
    • Restart
    • Shutdown
    • Standby
  • Remote Desktop
  • Remote Webcam
  • Password Recovery (Common Browsers and FTP Clients)
  • Keylogger (Unicode Support)
  • Download Files
  • Execute Files
  • Visit Website (hidden & visible)
  • Show Messagebox

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

  • {BLOCKED}.{BLOCKED}.85.227:1337

Dropping Routine

This Backdoor drops the following file(s), which it uses for its keylogging routine:

  • %Application Data%\Logs\MM-DD-YYYY -> {Current Date}

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Other Details

This Backdoor connects to the following URL(s) to get the affected system's IP address:

  • http://ip-api.com/

It does the following:

  • It adds the following scheduled tasks:
    • svchost
      • Executes at log on of any user
      • Executes the following command:
        • %Application Data%\SubDir\Client.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.104.07
FIRST VSAPI PATTERN DATE: 02 Mar 2018
VSAPI OPR PATTERN File: 14.105.00
VSAPI OPR PATTERN Date: 03 Mar 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

Restart in Safe Mode

[ Learn More ]

Step 4

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Application Data%\SubDir

Step 5

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 Startup%\scvhost.vbs
  • %Application Data%\Logs\MM-DD-YYYY
  • %System%\Tasks\svchost

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_QUSARRAT.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 this Knowledge Base page for more information.


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