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TROJ_BUZUS.BFG

May 04, 2013
 ALIASES:

Worm:Win32/Neeris.gen!C (Microsoft); W32/Hamweq.worm.h (McAfee); W32.IRCBot (Symantec); P2P-Worm.Win32.Palevo.kal (Kaspersky); Trojan.Win32.Buzus.bzaz (v) (Sunbelt); Backdoor.Generic.398219 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Trojan 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:

97,792 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

03 Oct 2012

Arrival Details

This Trojan 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 Trojan drops the following copies of itself into the affected system:

  • %System%\wbem\wmispv.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
WMI Service Client = "%System%\wbem\wmispv.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\AppCompatFlags\
Layers

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Shell Extensions
GON = "{malware path and file name}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\Minimal
WMI Service Client = "%System%\wbem\wmispv.exe"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\Network
WMI Service Client = "%System%\wbem\wmispv.exe"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\wbem\wmispv.exe = "%System%\wbem\wmispv.exe:*:Enabled:Windows Live"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile\AuthorizedApplications\
List
%System%\wbem\wmispv.exe = "%System%\wbem\wmispv.exe:*:Enabled:Windows Live"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\AppCompatFlags\
Layers
%System%\wbem\wmispv.exe = "DisableNXShowUI"

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

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\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags
    • Layers

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\CurrentVersion\Run
    • WMI Service Client = "%System%\wbem\wmispv.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Shell Extensions
    • GON = "{malware path and file name}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\SafeBoot\Minimal
    • WMI Service Client = "%System%\wbem\wmispv.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\SafeBoot\Network
    • WMI Service Client = "%System%\wbem\wmispv.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %System%\wbem\wmispv.exe = "%System%\wbem\wmispv.exe:*:Enabled:Windows Live"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile\AuthorizedApplications\List
    • %System%\wbem\wmispv.exe = "%System%\wbem\wmispv.exe:*:Enabled:Windows Live"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers
    • %System%\wbem\wmispv.exe = "DisableNXShowUI"

Step 5

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