ALIASES:

Suspicious.SillyFDC (Symantec); Trojan.Win32.Buzus.lnqt (Kaspersky); Trojan.Win32.Buzus (Sunbelt); Trojan.Generic.1754579 (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: 278,039 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 29 Jun 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 Root%\setup\setup.exe

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It creates the following folders:

  • %System Root%\setup

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{H3580V8K-M62E-T5N2-C4LD-I0Q4PF33S631}
StubPath = "%System Root%\setup\setup.exe Restart"

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
setup = "%System Root%\setup\setup.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\SOFTWARE\new

HKEY_LOCAL_MACHINE\Software\Microsoft\
Active Setup\Installed Components\{H3580V8K-M62E-T5N2-C4LD-I0Q4PF33S631}

HKEY_LOCAL_MACHINE\SOFTWARE\new

It adds the following registry entries:

HKEY_CURRENT_USER\Software\new
FileNameAtual = "{malware path and file name}"

HKEY_CURRENT_USER\Software\new
FirstExecution = "19/06/2012 -- 03:42"

HKEY_CURRENT_USER\Software\new
FileName = "DlzcId7kuKyvBHAzFDS66Mwr"

HKEY_LOCAL_MACHINE\SOFTWARE\new
HKLM = "zBGOmDI"

HKEY_CURRENT_USER\Software\new
HKCU = "zBGOmDI"

It deletes the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Active Setup\Installed Components\{H3580V8K-M62E-T5N2-C4LD-I0Q4PF33S631}

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_CURRENT_USER\SOFTWARE
    • new
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Active Setup\Installed Components
    • {H3580V8K-M62E-T5N2-C4LD-I0Q4PF33S631}
  • In HKEY_LOCAL_MACHINE\SOFTWARE
    • new

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\Active Setup\Installed Components\{H3580V8K-M62E-T5N2-C4LD-I0Q4PF33S631}
    • StubPath = "%System Root%\setup\setup.exe Restart"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • setup = "%System Root%\setup\setup.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • setup = "%System Root%\setup\setup.exe"
  • In HKEY_CURRENT_USER\Software\new
    • FileNameAtual = "{malware path and file name}"
  • In HKEY_CURRENT_USER\Software\new
    • FirstExecution = "19/06/2012 -- 03:42"
  • In HKEY_CURRENT_USER\Software\new
    • FileName = "DlzcId7kuKyvBHAzFDS66Mwr"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\new
    • HKLM = "zBGOmDI"
  • In HKEY_CURRENT_USER\Software\new
    • HKCU = "zBGOmDI"

Step 5

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 Root%\setup

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_BUZUS_0000040.TOMA. 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 7

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_CURRENT_USER\Software\Microsoft\Active Setup\Installed Components
    • {H3580V8K-M62E-T5N2-C4LD-I0Q4PF33S631}


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