TROJ_STARTP.SMA6


 ALIASES:

Trojan:JS/Startpage.J (Microsoft); StartPage-MJ (McAfee); ARC:Embedded, [winrar.knl]:Trojan.JS.StartPage.bi (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.4851983 (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:

634,888 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

04 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 creates the following folders:

  • %Program Files%\SogouInput
  • %Program Files%\SogouInput\5.0.0.3787
  • %Program Files%\Winrar

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

Other System Modifications

This Trojan deletes the following files:

  • %Desktop%.ini
  • %User Profile%\Quick Launch\Show Desktop.scf
  • %User Profile%\QUICK LAUNCH\Launch Internet Explorer Browser.lnk

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

It adds the following registry keys:

HKEY_CLASSES_ROOT\.knl

HKEY_CLASSES_ROOT\wFile

HKEY_CLASSES_ROOT\wFile\DefaultIcon

HKEY_CLASSES_ROOT\wFile\ScriptEngine

HKEY_CLASSES_ROOT\wFile\Shell

HKEY_CLASSES_ROOT\wFile\Shell\
Edit

HKEY_CLASSES_ROOT\wFile\Shell\
Edit\Command

HKEY_CLASSES_ROOT\wFile\Shell\
Open

HKEY_CLASSES_ROOT\wFile\Shell\
Open\Command

HKEY_CLASSES_ROOT\wFile\Shell\
Open2

HKEY_CLASSES_ROOT\wFile\Shell\
Open2\Command

HKEY_CLASSES_ROOT\wFile\Shell\
Print

HKEY_CLASSES_ROOT\wFile\Shell\
Print\Command

HKEY_CLASSES_ROOT\wFile\ShellEx

HKEY_CLASSES_ROOT\wFile\ShellEx\
DropHandler

HKEY_CLASSES_ROOT\wFile\ShellEx\
PropertySheetHandlers

HKEY_CLASSES_ROOT\wFile\ShellEx\
PropertySheetHandlers\WSHProps

HKEY_CLASSES_ROOT\qcfile\shell\
open\command

HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\
kswsvc

HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\
AntiVirus\Union

HKEY_CLASSES_ROOT\.qc

HKEY_CLASSES_ROOT\qcfile\DefaultIcon

HKEY_CLASSES_ROOT\qcfile\CLSID

HKEY_CLASSES_ROOT\qcfile\shellex\
IconHandler

HKEY_CLASSES_ROOT\qcfile\shellex\
ContextMenuHandlers

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

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

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
wFile
FriendlyTypeName = "@%SystemRoot%\System32\wshext.dll,-4805"

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_LOCAL_MACHINE\SOFTWARE\Classes\
qcfile\shell\open
CLSID = "{FBF23B40-E3F0-101B-8488-00AA003E56F8}"

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"

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}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DirectDraw\MostRecentApplication
Name = "iexplore.exe"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DirectDraw\MostRecentApplication
ID = "4117b81"

(Note: The default value data of the said registry entry is 41107b81.)

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"

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\aut1.tmp
  • %User Temp%\winrar.knl
  • %Desktop%\Internet Explorer.qc

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista and 7.)

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

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

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 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_CLASSES_ROOT
    • .knl
  • In HKEY_CLASSES_ROOT
    • wFile
  • In HKEY_CLASSES_ROOT\wFile
    • DefaultIcon
  • In HKEY_CLASSES_ROOT\wFile
    • ScriptEngine
  • In HKEY_CLASSES_ROOT\wFile
    • Shell
  • In HKEY_CLASSES_ROOT\wFile\Shell
    • Edit
  • In HKEY_CLASSES_ROOT\wFile\Shell\Edit
    • Command
  • In HKEY_CLASSES_ROOT\wFile\Shell
    • Open
  • In HKEY_CLASSES_ROOT\wFile\Shell\Open
    • Command
  • In HKEY_CLASSES_ROOT\wFile\Shell
    • Open2
  • In HKEY_CLASSES_ROOT\wFile\Shell\Open2
    • Command
  • In HKEY_CLASSES_ROOT\wFile\Shell
    • Print
  • In HKEY_CLASSES_ROOT\wFile\Shell\Print
    • Command
  • In HKEY_CLASSES_ROOT\wFile
    • ShellEx
  • In HKEY_CLASSES_ROOT\wFile\ShellEx
    • DropHandler
  • In HKEY_CLASSES_ROOT\wFile\ShellEx
    • PropertySheetHandlers
  • In HKEY_CLASSES_ROOT\wFile\ShellEx\PropertySheetHandlers
    • WSHProps
  • In HKEY_CLASSES_ROOT\qcfile\shell\open
    • command
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft
    • kswsvc
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Kingsoft\AntiVirus
    • Union
  • In HKEY_CLASSES_ROOT
    • .qc
  • In HKEY_CLASSES_ROOT\qcfile
    • DefaultIcon
  • In HKEY_CLASSES_ROOT\qcfile
    • CLSID
  • In HKEY_CLASSES_ROOT\qcfile\shellex
    • IconHandler
  • In HKEY_CLASSES_ROOT\qcfile\shellex
    • ContextMenuHandlers
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
    • HideDesktopIcons
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\HideDesktopIcons
    • NewStartPanel

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\Classes\wFile
    • FriendlyTypeName = "@%SystemRoot%\System32\wshext.dll,-4805"
  • 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_LOCAL_MACHINE\SOFTWARE\Classes\qcfile\shell\open
    • CLSID = "{FBF23B40-E3F0-101B-8488-00AA003E56F8}"
  • 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"

Step 5

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\CurrentVersion\Explorer\StartPage
    • From: Favorites = "{random values}"
      To: Favorites = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DirectDraw\MostRecentApplication
    • From: Name = "iexplore.exe"
      To: Name = ""iexplore.exe""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DirectDraw\MostRecentApplication
    • From: ID = "4117b81"
      To: ID = ""41107b81""

Step 6

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 Temp%\aut1.tmp
  • %User Temp%\winrar.knl
  • %Desktop%\Internet Explorer.qc

Step 7

Search and delete these folders

[ 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%\SogouInput
  • %Program Files%\SogouInput\5.0.0.3787
  • %Program Files%\Winrar

Step 8

Scan your computer with your Trend Micro product to delete files detected as TROJ_STARTP.SMA6. 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\Show Desktop.scf
  • %User Profile%\QUICK LAUNCH\Launch Internet Explorer Browser.lnk


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