TROJ_STARTP.SMA3

October 12, 2012
 ALIASES:

Trojan:JS/Startpage.KW (Microsoft); StartPage-MJ (McAfee); ARC:Embedded, [script.au3]:Trojan.Win32.Autoit.aen, [script.au3]:Trojan.Win32.Autoit.aen, [monitor.j (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.JS.Agent.EAD (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.

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

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

626,702 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

14 Mar 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 creates the following folders:

  • %Program Files%\Winrar

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

Other System Modifications

This Trojan deletes the following files:

  • %Desktop%.ini
  • %User Profile%\Quick Launch\Launch Internet Explorer Browser.lnk
  • %User Profile%\Quick Launch\Show Desktop.scf
  • %Windows%\fonts\msgothic.ttf
  • %Windows%\fonts\msuigoth.ttf
  • %Windows%\fonts\MSMINCHO.TTF
  • %Windows%\fonts\Gulim.ttf
  • %Windows%\fonts\Gulimche.ttf
  • %Windows%\fonts\Dotum.ttf
  • %Windows%\fonts\Batang.ttf
  • %Windows%\fonts\Gungsuh.ttf
  • %Windows%\fonts\Simsun.ttf
  • %Windows%\fonts\nsimsun.ttf
  • %Windows%\fonts\MingLiU.ttf
  • %Windows%\fonts\pmingliu.ttf
  • %System%\SET3.tmp
  • %System%\kbd101b.dll
  • %System%\SET5.tmp
  • %System%\kbd101c.dll
  • %System%\SET7.tmp
  • %System%\kbd103.dll
  • %System%\SET9.tmp
  • %System%\kbd106.dll
  • %System%\SETB.tmp
  • %System%\kbdjpn.dll
  • %System%\SETD.tmp
  • %System%\kbdkor.dll

(Note: %Desktop% is the current user's desktop, which is usually C:\Windows\Profiles\{user name}\Desktop on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Desktop on Windows NT, and C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\
kswsvc

HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\
AntiVirus\Union

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
HideDesktopIcons

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
HideDesktopIcons\NewStartPanel

HKEY_CLASSES_ROOT\lnkfile\shell\
open

HKEY_CLASSES_ROOT\lnkfile\shell\
open\command

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\
kswsvc
Version = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\
kswsvc
mainChannelID = "4"

HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\
kswsvc
subChannelID = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\
kswsvc
install = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\
kswsvc
forduba = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\
kswsvc
vt = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\
kswsvc
guid = "36526F63A4E84A7DBF8EA4CB0777F837"

HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\
kswsvc
autosetting = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\
AntiVirus\Union
UnionID = "31.18466"

HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\
AntiVirus\Union
PostExA = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
HideDesktopIcons
ClassicStartMenu = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
HideDesktopIcons\NewStartPanel
{871C5380-42A0-1069-A2EA-08002B30309D} = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
Enable = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
Size = "a"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
InitHits = "64"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
Factor = "14"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International
W2KLpk = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International
W2KLpk = "0"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
StartPage
Favorites = "{random values}"

(Note: The default value data of the said registry entry is {random values}.)

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
NoInternetIcon = "1"

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.lnk\ShellEx\{000214EE-0000-0000-C000-000000000046}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.lnk\ShellEx\{000214F9-0000-0000-C000-000000000046}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.lnk\ShellEx\{00021500-0000-0000-C000-000000000046}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.lnk\ShellEx\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.lnk\ShellEx

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
lnkfile\CLSID

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
lnkfile\shellex\ContextMenuHandlers\
{00021401-0000-0000-C000-000000000046}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
lnkfile\shellex\ContextMenuHandlers\
Offline Files

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
lnkfile\shellex\ContextMenuHandlers

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
lnkfile\shellex\PropertySheetHandlers\
ShimLayer Property Page

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
lnkfile\shellex\PropertySheetHandlers

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
lnkfile\shellex\DropHandler

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\aut1.tmp
  • %User Temp%\monitor.jse
  • %Desktop%\Internet Explorer.lnk
  • %System%\SET2.tmp
  • %System%\SET4.tmp
  • %System%\SET6.tmp
  • %System%\SET8.tmp
  • %System%\SETA.tmp
  • %System%\SETC.tmp
  • %System%\SET3.tmp
  • %System%\SET5.tmp
  • %System%\SET7.tmp
  • %System%\SET9.tmp
  • %System%\SETB.tmp
  • %System%\SETD.tmp

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %Desktop% is the current user's desktop, which is usually C:\Windows\Profiles\{user name}\Desktop on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Desktop on Windows NT, and C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

Other Details

This Trojan deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

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.

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\Kingsoft
    • kswsvc
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\AntiVirus
    • Union
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
    • HideDesktopIcons
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\HideDesktopIcons
    • NewStartPanel
  • In HKEY_CLASSES_ROOT\lnkfile\shell
    • open
  • In HKEY_CLASSES_ROOT\lnkfile\shell\open
    • command
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International
    • CpMRU

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\Kingsoft\kswsvc
    • Version = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\kswsvc
    • mainChannelID = "4"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\kswsvc
    • subChannelID = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\kswsvc
    • install = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\kswsvc
    • forduba = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\kswsvc
    • vt = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\kswsvc
    • guid = "36526F63A4E84A7DBF8EA4CB0777F837"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\kswsvc
    • autosetting = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\AntiVirus\Union
    • UnionID = "31.18466"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\AntiVirus\Union
    • PostExA = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\HideDesktopIcons
    • ClassicStartMenu = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\HideDesktopIcons\NewStartPanel
    • {871C5380-42A0-1069-A2EA-08002B30309D} = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
    • Enable = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
    • Size = "a"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
    • InitHits = "64"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
    • Factor = "14"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International
    • W2KLpk = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International
    • W2KLpk = "0"

Step 5

Restore this modified 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\Microsoft\Windows\CurrentVersion\Explorer\StartPage
    • From: Favorites = "{random values}"
      To: Favorites = ""{random values}""

Step 6

Search and delete these files

[ Learn More ]
There may be some component files 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 Temp%\aut1.tmp
  • %User Temp%\monitor.jse
  • %Desktop%\Internet Explorer.lnk
  • %System%\SET2.tmp
  • %System%\SET4.tmp
  • %System%\SET6.tmp
  • %System%\SET8.tmp
  • %System%\SETA.tmp
  • %System%\SETC.tmp
  • %System%\SET3.tmp
  • %System%\SET5.tmp
  • %System%\SET7.tmp
  • %System%\SET9.tmp
  • %System%\SETB.tmp
  • %System%\SETD.tmp

Step 7

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%\Winrar

Step 8

Scan your computer with your Trend Micro product to delete files detected as TROJ_STARTP.SMA3. 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 9

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.

  • %Desktop%.ini
  • %User Profile%\Quick Launch\Launch Internet Explorer Browser.lnk
  • %User Profile%\Quick Launch\Show Desktop.scf
  • %Windows%\fonts\msgothic.ttf
  • %Windows%\fonts\msuigoth.ttf
  • %Windows%\fonts\MSMINCHO.TTF
  • %Windows%\fonts\Gulim.ttf
  • %Windows%\fonts\Gulimche.ttf
  • %Windows%\fonts\Dotum.ttf
  • %Windows%\fonts\Batang.ttf
  • %Windows%\fonts\Gungsuh.ttf
  • %Windows%\fonts\Simsun.ttf
  • %Windows%\fonts\nsimsun.ttf
  • %Windows%\fonts\MingLiU.ttf
  • %Windows%\fonts\pmingliu.ttf
  • %System%\SET3.tmp
  • %System%\kbd101b.dll
  • %System%\SET5.tmp
  • %System%\kbd101c.dll
  • %System%\SET7.tmp
  • %System%\kbd103.dll
  • %System%\SET9.tmp
  • %System%\kbd106.dll
  • %System%\SETB.tmp
  • %System%\kbdjpn.dll
  • %System%\SETD.tmp
  • %System%\kbdkor.dll

Step 10

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_LOCAL_MACHINE\SOFTWARE\Classes\.lnk\ShellEx
    • {000214EE-0000-0000-C000-000000000046}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.lnk\ShellEx
    • {000214F9-0000-0000-C000-000000000046}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.lnk\ShellEx
    • {00021500-0000-0000-C000-000000000046}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.lnk\ShellEx
    • {BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.lnk
    • ShellEx
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\lnkfile
    • CLSID
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\lnkfile\shellex\ContextMenuHandlers
    • {00021401-0000-0000-C000-000000000046}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\lnkfile\shellex\ContextMenuHandlers
    • Offline Files
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\lnkfile\shellex
    • ContextMenuHandlers
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\lnkfile\shellex\PropertySheetHandlers
    • ShimLayer Property Page
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\lnkfile\shellex
    • PropertySheetHandlers
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\lnkfile\shellex
    • DropHandler


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