TROJ_BUZUS.VKL


 ALIASES:

RDN/Generic.bfr!gc (McAfee); Trojan.Shylock (Symantec); Trojan.Win32.Buzus.oipa (Kaspersky); Trojan.Win32.Buzus (Sunbelt); Trojan horse Inject2.TSP (AVG)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 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.

It disables Task Manager, Registry Editor, and Folder Options.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

266,968 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

17 Jul 2014

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%\UpdaterWin\svhost.exe

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

It creates the following folders:

  • %System%\UpdaterWin

(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
UpdaterWin = "%System%\UpdaterWin\svhost.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
UpdaterWin = "%System%\UpdaterWin\svhost.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{88X17B87-OWCM-BTL3-QXB3-3VX6X2GLI0DU}
StubPath = "%System%\UpdaterWin\svhost.exe restart"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunOnce
Microsoft = "%System%\UpdaterWin\svhost.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
Microsoft = "%System%\UpdaterWin\svhost.exe"

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "explorer.exe %System%\UpdaterWin\svhost.exe"

(Note: The default value data of the said registry entry is Explorer.exe.)

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\SOFTWARE\n1sAEBf3

HKEY_LOCAL_MACHINE\Software\Microsoft\
Active Setup\Installed Components\{88X17B87-OWCM-BTL3-QXB3-3VX6X2GLI0DU}

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run

It adds the following registry entries:

HKEY_CURRENT_USER\Software\n1sAEBf3
ServerStarted = "3/6/2014 7:52:33 AM"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
Load = "%System%\UpdaterWin\svhost.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "explorer.exe %System%\UpdaterWin\svhost.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
Microsoft = "%System%\UpdaterWin\svhost.exe"

HKEY_CURRENT_USER\Software\n1sAEBf3
InstalledServer = "%System%\UpdaterWin\svhost.exe"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
Load = "%System%\UpdaterWin\svhost.exe"

It creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
Microsoft = "%System%\UpdaterWin\svhost.exe"

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\Windows\n1sAEBf3.cfg
  • %User Profile%\Windows\n1sAEBf3.xtr

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://www.{BLOCKED}e.qc.ca/js/plugin.xtr
  • {BLOCKED}0.1
  • {BLOCKED}186.60

It deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.700

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

Identify and delete files detected as TROJ_BUZUS.VKL using either the Startup Disk or Recovery Console

[ Learn More ]

Step 3

Enable Registry Editor, Task Manager, and Folder options

[ Learn More ]
By doing this step, you also enable other applications/programs disabled by this malware/grayware/spyware.

Step 4

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_CURRENT_USER\SOFTWARE
    • n1sAEBf3
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Active Setup\Installed Components
    • {88X17B87-OWCM-BTL3-QXB3-3VX6X2GLI0DU}
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • Run
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • Run

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
    • UpdaterWin = "%System%\UpdaterWin\svhost.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • UpdaterWin = "%System%\UpdaterWin\svhost.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{88X17B87-OWCM-BTL3-QXB3-3VX6X2GLI0DU}
    • StubPath = "%System%\UpdaterWin\svhost.exe restart"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
    • Microsoft = "%System%\UpdaterWin\svhost.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
    • Microsoft = "%System%\UpdaterWin\svhost.exe"
  • In HKEY_CURRENT_USER\Software\n1sAEBf3
    • ServerStarted = "3/6/2014 7:52:33 AM"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows
    • Load = "%System%\UpdaterWin\svhost.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
    • Shell = "explorer.exe %System%\UpdaterWin\svhost.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
    • Microsoft = "%System%\UpdaterWin\svhost.exe"
  • In HKEY_CURRENT_USER\Software\n1sAEBf3
    • InstalledServer = "%System%\UpdaterWin\svhost.exe"

Step 6

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\Windows NT\CurrentVersion\Windows
    • Load = "%System%\UpdaterWin\svhost.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Shell = "explorer.exe %System%\UpdaterWin\svhost.exe"
      To: Shell = ""Explorer.exe""

Step 7

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.
  • %User Profile%\Windows\n1sAEBf3.cfg
  • %User Profile%\Windows\n1sAEBf3.xtr

Step 8

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.
  • %System%\UpdaterWin

Step 9

Scan your computer with your Trend Micro product to delete files detected as TROJ_BUZUS.VKL. 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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