ALIASES:

TrojanSpy:Win32/Banker, TrojanSpy:Win32/Banker (Microsoft); Mal/PdfExDr-B, Mal/EncPk-CK (Sophos); Trojan horse PSW.Banker6.CFIF.dropper (AVG)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:
 SYSTEM IMPACT RATING:
 INFORMATION EXPOSURE:

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 75,776 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 11 Jul 2015

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 creates the following folders:

  • %Program Files%\Common Files\Plugins

(Note: %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.)

Autostart Technique

This spyware registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\BSXerv\Parameters

Other System Modifications

This spyware deletes the following files:

  • %Program Files%\Common Files\Plugins\index.txt

(Note: %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 adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost
BSXerv = "BSXerv,ÿBS Server"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\BSXerv
Description = "BSerc mornitor for V3 AntiVirius"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\BSXerv
DisplayName = "BS Server"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\BSXerv
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\BSXerv
Group = "Com Infrastructure"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\BSXerv
ObjectName = "LocalSystem"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\BSXerv
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\BSXerv
Type = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\BSXerv
FailureAction = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\BSXerv
ImagePath = "%SystemRoot%\system32\svchost -k BSXerv"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\BSXerv\Parameters
ServiceDll = "%System%\v2BSXerv.dll"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\BSXerv\Parameters
ServiceMain = "DebugEntry"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DataAccess
xyz = "{malware path and file name}"

Dropping Routine

This spyware drops the following files:

  • %System%\v2BSXerv.dll
  • %System%\twlsp.dll
  • %Windows%\profiles.pbk

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

Other Details

This spyware deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.750

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

Restart in Safe Mode

[ Learn More ]

Step 3

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
    • Parameters

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\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost
    • BSXerv = "BSXerv,ÿBS Server"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BSXerv
    • Description = "BSerc mornitor for V3 AntiVirius"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BSXerv
    • DisplayName = "BS Server"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BSXerv
    • ErrorControl = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BSXerv
    • Group = "Com Infrastructure"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BSXerv
    • ObjectName = "LocalSystem"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BSXerv
    • Start = "2"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BSXerv
    • Type = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BSXerv
    • FailureAction = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BSXerv
    • ImagePath = "%SystemRoot%\system32\svchost -k BSXerv"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BSXerv\Parameters
    • ServiceDll = "%System%\v2BSXerv.dll"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BSXerv\Parameters
    • ServiceMain = "DebugEntry"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DataAccess
    • xyz = "{malware path and file name}"

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %System%\v2BSXerv.dll
  • %System%\twlsp.dll
  • %Windows%\profiles.pbk

Step 6

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.
  • %Program Files%\Common Files\Plugins

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_BANKER.CHX. 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 8

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %Program Files%\Common Files\Plugins\index.txt


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