BKDR_HANCITOR.YYSWB

September 10, 2016
 Analysis by: Cris Nowell Pantanilla
 ALIASES:

Trojan:Win32/Dynamer!ac (Microsoft), W32/Cutwail.AJ (exact) (FPROT)

 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

This backdoor may be dropped by other malware.

It gathers information and reports it to its servers.

  TECHNICAL DETAILS

File Size:

46,592 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

08 Sep 2016

Payload:

Connects to URLs/IPs

Arrival Details

This backdoor may be dropped by the following malware:

  • W2KM_HANCITOR.YYSWB

Installation

This backdoor drops and executes the following files:

  • %Temp%\{random value}.tmp -> drops copy %System%\WinHost32.exe

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

It injects codes into the following process(es):

  • svchost.exe

Autostart Technique

This backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
WinHost32 = "%System%\WinHost32.exe"

Backdoor Routine

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

  • http://{BLOCKED}rlittbet.com/ls4/gate.php
  • http://{BLOCKED}johnet.ru/ls4/gate.php
  • http://{BLOCKED}tsandthat.ru/ls4/gate.php

Other Details

This backdoor connects to the following URL(s) to check for an Internet connection:

  • www.google.com

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

  • api.ipify.org

It does the following:

  • It is capable of downloading and executing file on the affected system. As a result, behavior of the downloaded file is exhibited on the affected system.

It gathers the following information and reports it to its servers:

  • OS Version
  • IP Address
  • Machine GUID

    The information are posted to the server in the following format: GUID={machine guid}&BUILD=&INFO={info}&IP={IP address}&TYPE=1&WIN={OS version}

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.764.07

FIRST VSAPI PATTERN DATE:

08 Sep 2016

VSAPI OPR PATTERN File:

12.765.00

VSAPI OPR PATTERN Date:

09 Sep 2016

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

Remove malware/grayware files that dropped/downloaded BKDR_HANCITOR.YYSWB. (Note: Please skip this step if the threats listed below have already been removed.)

     W2KM_HANCITOR.YYSWB

Step 3

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 4

Restart in Safe Mode

[ Learn More ]

Step 5

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\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • WinHost32 = "%System%\WinHost32.exe"

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_HANCITOR.YYSWB. 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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