Analysis by: Francis Xavier Antazo

 PLATFORM:

Windows

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

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This spyware 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: 119296 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 12 Aug 2015
Payload: Connects to URLs/IPs, Steals information

Arrival Details

This spyware 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 spyware drops the following files:

  • %Windows%\profiles.pbk
  • %Program Files%\Common Files\Plugins\index.txt

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

It drops the following component file(s):

  • %System%\v2BSXerv.dll (to be detected as TSPY_WEDOTS.B)
  • %System%\twlsp.dll (to be detected as TSPY_WEDOTS.B)

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

It adds the following processes:

  • IEXPLORE.EXE
  • svchost.exe

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

  • Global\EsXPSwitchUserApp

Autostart Technique

This spyware registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\BSXerv
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\BSXerv
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\BSXerv
ImagePath = "%SystemRoot%\system32\svchost -k BSXerv"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\BSXerv
DisplayName = "BS Server"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\BSXerv
Description = "BSerc mornitor for V3 AntiVirius"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\BSXerv
Group = "Com Infrastructure"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\BSXerv\Parameters
ServiceDll = "%System%\v2BSXerv.dll"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\BSXerv\Parameters
ServiceMain = "PutEntity"

Other System Modifications

This spyware adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DataAccess
vpn = "210.124.84.16"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Start Page = "www.naver.com"

(Note: The default value data of the said registry entry is "{User Preference}".)

Information Theft

This spyware gathers the following data:

  • Nested Certificate Based Public Key Infrastructure (NPKI)

NOTES:

The malware searches all drives and folders for the following folder:

  • \NPKI\

It connects to the following URLs to get the IP of the C&C server:

  • http://iframe.{BLOCKED}8.com/ip2city.asp

It performs DNS spoofing by redirecting to the C&C server when users connect to the following sites:

  • http://www.epostbank.kr/
  • http://epostbank.kr/
  • http://epost.kr/
  • http://epostbank.co.kr/
  • http://www.epostbank.co.kr/
  • http://kfcc.com/
  • http://www.kfcc.com/
  • http://kfcc.co.kr/
  • http://www.kfcc.co.kr/
  • http://www.ibk.kr/
  • http://banking.ibk.co.kr/
  • http://mybank.ibk.co.kr/
  • http://ibk.kr/
  • http://ibk.co.kr/
  • http://www.ibk.co.kr/
  • http://keb.co.kr/
  • http://online.keb.co.kr/
  • http://ebank.keb.co.kr/
  • http://www.keb.co.kr/
  • http://banking.nonghyup.co.kr/
  • http://nonghyup.co.kr/
  • http://www.nonghyup.co.kr/
  • http://banking.nonghyup.com/
  • http://nonghyup.com/
  • http://www.nonghyup.com/
  • http://hanabank.co.kr/
  • http://www.hanabank.co.kr/
  • http://www.hanabank.com/
  • http://hanabank.com/
  • http://shinhan.com/
  • http://www.shinhanbank.com/
  • http://banking.shinhan.com/
  • http://banking.shinhanbank.co.kr/
  • http://shinhanbank.com/
  • http://shinhanbank.co.kr/
  • http://www.shinhanbank.co.kr/
  • http://www.shinhan.com/
  • http://wooribank.kr/
  • http://www.wooribank.kr/
  • http://www.woori.co.kr/
  • http://wooribank.com/
  • http://www.wooribank.com/
  • http://banking.kbstar.co.kr/
  • http://banking.kbstar.com/
  • http://kbbank.com/
  • http://kb.kr/
  • http://www.kb.co.kr/
  • http://kbstar.co.kr/
  • http://www.kbstar.co.kr/
  • http://kbstar.com/
  • http://www.kbstar.com/

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.854.05
FIRST VSAPI PATTERN DATE: 14 Aug 2015

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 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.  
  • C:\WINDOWS\profiles.pbk
  • C:\Program Files\Common Files\Plugins\index.txt

Step 5

Delete this registry key

[ 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
    • BSXerv

Step 6

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\DataAccess
    • vpn = "210.124.84.16"

Step 7

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • From: Start Page = "www.naver.com"
      To: Start Page = "{User Preference}"

Step 8

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