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WORM_AUTORUN.BUK

July 04, 2013
 ALIASES:

Worm:Win32/Autorun.CH (Microsoft); W32/Autorun.worm.ch (McAfee); W32.SillyFDC (Symantec); Trojan.Win32.Cosmu.cvd (Kaspersky); Worm.Win32.Autorun.eee (v) (Sunbelt); Worm/AutoRun.PA (AVG)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This worm 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:

2,162,688 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

04 Jul 2013

Arrival Details

This worm 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 worm creates the following folders:

  • %System%\dllcache\Recycler.{645FF040-5081-101B-9F08-00AA002F954E}

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

Other System Modifications

This worm adds the following registry keys:

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
trial version\trial

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
ctfmon.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
taskmgr.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
boot.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
autorun.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
autoruns.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
auto.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
msconfig.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
procexp.exe

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunOnce

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\System\
Scripts\Logoff\0

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\System\
Scripts\Logoff\0\
0

HKEY_LOCAL_MACHINE\Software\Policies\
Microsoft\Windows\System\
Scripts\Shutdown\0

HKEY_LOCAL_MACHINE\Software\Policies\
Microsoft\Windows\System\
Scripts\Shutdown\0\
0

HKEY_LOCAL_MACHINE\Software\Policies\
Microsoft\Windows\System\
Scripts\Startup\0

HKEY_LOCAL_MACHINE\Software\Policies\
Microsoft\Windows\System\
Scripts\Startup\0\
0

It adds the following registry entries:

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
trial version\trial
date1 = "6/21/2013"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
ctfmon.exe
Debugger = "%Windows%\Fonts\Fonts.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
taskmgr.exe
Debugger = "%Windows%\Fonts\tskmgr.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
boot.exe
Debugger = "%Windows%\Fonts\fonts.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
autorun.exe
Debugger = "%System%\drivers\drivers.cab.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
autoruns.exe
Debugger = "%System%\drivers\drivers.cab.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
auto.exe
Debugger = "%System%\drivers\drivers.cab.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
msconfig.exe
Debugger = "%Windows%\Media\rndll32.pif"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
procexp.exe
Debugger = "%Windows%\pchealth\helpctr\binaries\HelpHost.com"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
sys = "%Windows%\Fonts\Fonts.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
DisableStatusMessages = "1"

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\System\
Scripts\Logoff\0
DisplayName = "Local Group Policy"

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\System\
Scripts\Logoff\0
GPO-ID = "LocalGPO"

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\System\
Scripts\Logoff\0
GPOName = "Local Group Policy"

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\System\
Scripts\Logoff\0
SOM-ID = "Local"

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\System\
Scripts\Logoff\0\
0
Script = "%Windows%\Cursors\Boom.vbs"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\System\
Scripts\Shutdown\0
DisplayName = "Local Group Policy"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\System\
Scripts\Shutdown\0
GPO-ID = "LocalGPO"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\System\
Scripts\Shutdown\0
GPOName = "Local Group Policy"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\System\
Scripts\Shutdown\0
SOM-ID = "Local"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\System\
Scripts\Shutdown\0\
0
Script = "%Windows%\Cursors\Boom.vbs"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\System\
Scripts\Startup\0
DisplayName = "Local Group Policy"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\System\
Scripts\Startup\0
GPO-ID = "LocalGPO"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\System\
Scripts\Startup\0
GPOName = "Local Group Policy"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\System\
Scripts\Startup\0
SOM-ID = "Local"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\System\
Scripts\Startup\0\
0
Script = "%Windows%\Cursors\Boom.vbs"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
exefile
NeverShowExt = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
comfile
NeverShowExt = "1"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\SuperHidden
ValueName = "ShowSuperHiden"

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

HKEY_CURRENT_USER\Control Panel\Desktop
SCRNSAVE.EXE = "%Windows%\pchealth\helpctr\binaries\HelpHost.com"

(Note: The default value data of the said registry entry is %Windows%\system32\logon.scr.)

HKEY_CURRENT_USER\Control Panel\Desktop
ScreenSaveTimeOut = "30"

(Note: The default value data of the said registry entry is 600.)

HKEY_CURRENT_USER\Control Panel\Desktop
AutoEndTasks = "1"

(Note: The default value data of the said registry entry is 0.)

Dropping Routine

This worm drops the following files:

  • %System%\dllcache\autorun.inf
  • %Windows%\Cursors\Boom.vbs
  • %System%\dllcache\tskmgr.exe
  • %Windows%\Fonts\wav.wav

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

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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

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\VB and VBA Program Settings version
    • trial
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
    • ctfmon.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
    • taskmgr.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
    • boot.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
    • autorun.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
    • autoruns.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
    • auto.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
    • msconfig.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
    • procexp.exe
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion
    • RunOnce
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer
    • Run
  • In HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\System\Scripts\Logoff
    • 0
  • In HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\System\Scripts\Logoff
    • 0
  • In HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\System\Scripts\Shutdown
    • 0
  • In HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\System\Scripts\Shutdown
    • 0
  • In HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\System\Scripts\Startup
    • 0
  • In HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\System\Scripts\Startup
    • 0

Step 3

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_CURRENT_USER\Software\VB and VBA Program Settings\trial version\trial
    • date1 = "6/21/2013"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\ctfmon.exe
    • Debugger = "%Windows%\Fonts\Fonts.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\taskmgr.exe
    • Debugger = "%Windows%\Fonts\tskmgr.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\boot.exe
    • Debugger = "%Windows%\Fonts\fonts.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\autorun.exe
    • Debugger = "%System%\drivers\drivers.cab.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\autoruns.exe
    • Debugger = "%System%\drivers\drivers.cab.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\auto.exe
    • Debugger = "%System%\drivers\drivers.cab.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\msconfig.exe
    • Debugger = "%Windows%\Media\rndll32.pif"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\procexp.exe
    • Debugger = "%Windows%\pchealth\helpctr\binaries\HelpHost.com"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
    • sys = "%Windows%\Fonts\Fonts.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system
    • DisableStatusMessages = "1"
  • In HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\System\Scripts\Logoff\0
    • DisplayName = "Local Group Policy"
  • In HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\System\Scripts\Logoff\0
    • GPO-ID = "LocalGPO"
  • In HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\System\Scripts\Logoff\0
    • GPOName = "Local Group Policy"
  • In HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\System\Scripts\Logoff\0
    • SOM-ID = "Local"
  • In HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\System\Scripts\Logoff\0\0
    • Script = "%Windows%\Cursors\Boom.vbs"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\System\Scripts\Shutdown\0
    • DisplayName = "Local Group Policy"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\System\Scripts\Shutdown\0
    • GPO-ID = "LocalGPO"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\System\Scripts\Shutdown\0
    • GPOName = "Local Group Policy"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\System\Scripts\Shutdown\0
    • SOM-ID = "Local"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\System\Scripts\Shutdown\0\0
    • Script = "%Windows%\Cursors\Boom.vbs"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\System\Scripts\Startup\0
    • DisplayName = "Local Group Policy"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\System\Scripts\Startup\0
    • GPO-ID = "LocalGPO"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\System\Scripts\Startup\0
    • GPOName = "Local Group Policy"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\System\Scripts\Startup\0
    • SOM-ID = "Local"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\System\Scripts\Startup\0\0
    • Script = "%Windows%\Cursors\Boom.vbs"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\exefile
    • NeverShowExt = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\comfile
    • NeverShowExt = "1"

Step 4

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\SuperHidden
    • From: ValueName = "ShowSuperHiden"
      To: ValueName = ""ShowSuperHidden""
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: SCRNSAVE.EXE = "%Windows%\pchealth\helpctr\binaries\HelpHost.com"
      To: SCRNSAVE.EXE = ""%Windows%\system32\logon.scr""
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: ScreenSaveTimeOut = "30"
      To: ScreenSaveTimeOut = ""600""
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: AutoEndTasks = "1"
      To: AutoEndTasks = ""0""

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%\dllcache\autorun.inf
  • %Windows%\Cursors\Boom.vbs
  • %System%\dllcache\tskmgr.exe
  • %Windows%\Fonts\wav.wav

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.
  • %System%\dllcache\Recycler.{645FF040-5081-101B-9F08-00AA002F954E}

Step 7

Scan your computer with your Trend Micro product to delete files detected as WORM_AUTORUN.BUK. 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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