TROJ_TRATS.SMUM


 ALIASES:

Trojan:Win32/Meredrop (Microsoft); Generic Dropper!djf (McAfee); Trojan.ADH (Symantec); ARC:Inno, [data0000]:Trojan.JS.StartPage.ck, [data0000]:Trojan.JS.StartPage.ck, [data0000]:Trojan.JS (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.4501883 (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.

  TECHNICAL DETAILS

File Size:

309,031 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

05 Nov 2011

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:

  • %User Temp%\is-QF09P.tmp
  • %User Temp%\is-MM691.tmp
  • %User Temp%\is-MM691.tmp\_isetup
  • %Program Files%\Internet Explorer\MUI
  • %Program Files%\lnkfiles\

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

Other System Modifications

This Trojan adds the following registry keys:

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

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

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\ShellNoRoam\MUICache
@C:\WINDOWS\system32\SHELL32.dll,-30520 = "Internet Explorer"

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

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

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

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2

(Note: The default value data of the said registry entry is 2.)

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

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\is-qf09p.tmp\{malware file name}.tmp
  • %User Temp%\is-MM691.tmp\_isetup\_RegDLL.tmp
  • %User Temp%\is-MM691.tmp\_isetup\_shfoldr.dll
  • %Program Files%\Messenger\is-OP1F1.tmp
  • %Program Files%\Messenger\is-5HLTA.tmp
  • %System%\is-HP2M1.tmp
  • %System%\is-OKB7P.tmp
  • %System%\is-EA9FQ.tmp
  • %System%\is-IJA48.tmp
  • %Program Files%\Internet Explorer\MUI\iexplore.exe

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

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\HideDesktopIcons
    • ClassicStartMenu
  • 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_CURRENT_USER\Software\Microsoft\Windows\ShellNoRoam\MUICache
    • @C:\WINDOWS\system32\SHELL32.dll,-30520="Internet Explorer"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\HideDesktopIcons\ClassicStartMenu
    • {871C5380-42A0-1069-A2EA-08002B30309D}=1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\HideDesktopIcons\NewStartPanel
    • {871C5380-42A0-1069-A2EA-08002B30309D}=1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\HideDesktopIcons
    • ClassicStartMenu=1

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\Advanced
    • From: Hidden=2
      To: Hidden=2
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\StartPage
    • From: Favorites={random values}
      To: Favorites={random values}

Step 6

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.
  • %User Temp%\is-QF09P.tmp
  • %User Temp%\is-MM691.tmp
  • %User Temp%\is-MM691.tmp\_isetup
  • %Program Files%\Internet Explorer\MUI
  • %Program Files%\lnkfiles\

Step 7

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%\is-qf09p.tmp\{malware file name}.tmp
  • %User Temp%\is-MM691.tmp\_isetup\_RegDLL.tmp
  • %User Temp%\is-MM691.tmp\_isetup\_shfoldr.dll
  • %Program Files%\Messenger\is-OP1F1.tmp
  • %Program Files%\Messenger\is-5HLTA.tmp
  • %System%\is-HP2M1.tmp
  • %System%\is-OKB7P.tmp
  • %System%\is-EA9FQ.tmp
  • %System%\is-IJA48.tmp
  • %Program Files%\Internet Explorer\MUI\iexplore.exe

Step 8

Scan your computer with your Trend Micro product to delete files detected as TROJ_TRATS.SMUM. 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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