ALIASES:

Trojan:Win32/Agent (Microsoft); :VBObfus.ax (McAfee); ARC:Rsrc-Package, ARC:[data0000.cab]:CAB, ARC:[data0000.cab/msgr11us.exe]:NSIS, ARC:[data0000.cab/ms (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); MemScan:Trojan.Spy.VB.NIP (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: 536,064 bytes
File Type: EXE
Initial Samples Received Date: 01 Oct 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%\IXP000.TMP
  • %User Profile%\Application Data\Dir
  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\ADMINI~1
  • %User Profile%\LOCALS~1
  • %User Temp%\nsi2.tmp
  • %User Temp%\nsa4.tmp
  • %Program Files%\Yahoo!

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

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunOnce
wextract_cleanup0 = "rundll32.exe %System%\advpack.dll,DelNodeRunDLL32 "%User Temp%\IXP000.TMP\""

Other System Modifications

This Trojan deletes the following files:

  • %User Temp%\IXP000.TMP\winamp.Exe
  • %User Temp%\nst1.tmp
  • %User Temp%\nsi2.tmp
  • %User Temp%\nsa3.tmp
  • %User Temp%\nsa4.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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It deletes the following folders:

  • %User Temp%\IXP000.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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Visual Basic\6.0

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\MediaResources\msvideo

HKEY_CURRENT_USER\Software\Yahoo\
SuiteInstaller

HKEY_CURRENT_USER\Software\Yahoo\
pager

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
winexplorer = "%User Profile%\Dir\winexplorer.exe"

HKEY_CURRENT_USER\Software\Yahoo\
SuiteInstaller
Full = "ezU4QzEyMDY1LUMzNDktNEI2MC05MzRBLTUzRjNEQUZCODAwRX0="

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyHttp1.1 = 1

HKEY_CURRENT_USER\Software\Yahoo\
pager
MD_ID_VALUE = "ID=ezU4QzEyMDY1LUMzNDktNEI2MC05MzRBLTUzRjNEQUZCODAwRX0="

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Start Page = "http://www.{BLOCKED}o.com/?ilc=8"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Start Page = "http://www.{BLOCKED}o.com/?ilc=8"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd={SUB_PRD}&clcid={SUB_CLSID}&pver={SUB_PVER}&ar=home.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Default_Page_URL = "http://www.{BLOCKED}o.com/?ilc=8"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome.)

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

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DirectDraw\MostRecentApplication
ID = 4aa7ac42

(Note: The default value data of the said registry entry is 41107b3f.)

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

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

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

(Note: The default value data of the said registry entry is 41107b3f.)

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\IXP000.TMP\TMP4351$.TMP
  • %User Temp%\IXP000.TMP\msgr11us.exe
  • %User Temp%\IXP000.TMP\winamp.Exe
  • %User Profile%\Dir\winexplorer.exe
  • %System Root%\runner.bat
  • %User Profile%\Dir\Dated.dat
  • %User Temp%\nsi2.tmp\System.dll
  • %User Temp%\nsi2.tmp\bootstrap.ini
  • %User Temp%\nsi2.tmp\Base64.dll
  • %User Temp%\nsi2.tmp\ymsgr_suite_setup.exe
  • %User Temp%\nsi2.tmp\YExecShell.dll
  • %User Temp%\nsa4.tmp\System.dll
  • %User Temp%\nsa4.tmp\InetLoad_vms.dll
  • %User Temp%\nsa4.tmp\ymsgr11_us.ini
  • %User Temp%\nsa4.tmp\nsp5.tmp.htm
  • %User Temp%\nsa4.tmp\nsw6.tmp.htm
  • %User Temp%\nsa4.tmp\s1.bmp
  • %User Temp%\nsa4.tmp\s2.bmp
  • %User Temp%\nsa4.tmp\s3.bmp
  • %User Temp%\nsa4.tmp\s4.bmp
  • %User Temp%\nsa4.tmp\s5.bmp
  • %User Temp%\nsa4.tmp\ywiseextU.dll
  • %User Temp%\nsa4.tmp\eula.rtf
  • %User Temp%\nsa4.tmp\finish.ini
  • %User Temp%\nsa4.tmp\legal.ini
  • %User Temp%\nsa4.tmp\review.ini
  • %User Temp%\nsa4.tmp\software.ini
  • %User Temp%\nsa4.tmp\welcome.ini
  • %User Temp%\nsa4.tmp\modern-header.bmp
  • %User Temp%\nsa4.tmp\InstallOptions.dll
  • %User Temp%\nsa4.tmp\bb.html
  • %User Temp%\nsa4.tmp\stack.dll
  • %User Temp%\nsa4.tmp\ymsgr_inst.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, or C:\Users\{user name}\AppData\Local\Temp 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.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • /msgr/11/ga/ini/ymsgr11_us.ini
  • /ycontent/stats.php?version=0011.0000.0000.2014&language=us&OS=5.1&EVENT=LaunchU&ID=ezU4QzEyMDY1LUMzNDktNEI2MC05MzRBLTUzRjNEQUZCODAwRX0=
  • /appusage.asp
  • /ymessenger/dl/msgr11/ymsgr1100_2014_us.exe?m=application%2foctet-stream&s=1bb083517d3595b3ff880fa0e339e9e6

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\Microsoft\Visual Basic
    • 6.0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MediaResources
    • msvideo
  • In HKEY_CURRENT_USER\Software\Yahoo
    • SuiteInstaller
  • In HKEY_CURRENT_USER\Software\Yahoo
    • pager

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\Windows\CurrentVersion\RunOnce
    • wextract_cleanup0="rundll32.exe %System%\advpack.dll,DelNodeRunDLL32 "%User Temp%\IXP000.TMP\""
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • winexplorer="%User Profile%\Dir\winexplorer.exe"
  • In HKEY_CURRENT_USER\Software\Yahoo\SuiteInstaller
    • Full="ezU4QzEyMDY1LUMzNDktNEI2MC05MzRBLTUzRjNEQUZCODAwRX0="
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • ProxyHttp1.1=1
  • In HKEY_CURRENT_USER\Software\Yahoo\pager
    • MD_ID_VALUE="ID=ezU4QzEyMDY1LUMzNDktNEI2MC05MzRBLTUzRjNEQUZCODAwRX0="

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\Internet Explorer\Main
    • From: Start Page="http://www.{BLOCKED}o.com/?ilc=8"
      To: Start Page=http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
    • From: Start Page="http://www.{BLOCKED}o.com/?ilc=8"
      To: Start Page=http://www.microsoft.com/isapi/redir.dll?prd={SUB_PRD}&clcid={SUB_CLSID}&pver={SUB_PVER}&ar=home
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
    • From: Default_Page_URL="http://www.{BLOCKED}o.com/?ilc=8"
      To: Default_Page_URL=http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DirectDraw\MostRecentApplication
    • From: Name="ymsgr_suite_setup.exe"
      To: Name=mshta.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DirectDraw\MostRecentApplication
    • From: ID=4aa7ac42
      To: ID=41107b3f
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DirectDraw\MostRecentApplication
    • From: Name="iexplore.exe"
      To: Name=mshta.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DirectDraw\MostRecentApplication
    • From: ID=4117b81
      To: ID=41107b3f

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%\IXP000.TMP
  • %User Profile%\Application Data\Dir
  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\ADMINI~1
  • %User Profile%\LOCALS~1
  • %User Temp%\nsi2.tmp
  • %User Temp%\nsa4.tmp
  • %Program Files%\Yahoo!

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%\IXP000.TMP\TMP4351$.TMP
  • %User Temp%\IXP000.TMP\msgr11us.exe
  • %User Temp%\IXP000.TMP\winamp.Exe
  • %User Profile%\Dir\winexplorer.exe
  • %System Root%\runner.bat
  • %User Profile%\Dir\Dated.dat
  • %User Temp%\nsi2.tmp\System.dll
  • %User Temp%\nsi2.tmp\bootstrap.ini
  • %User Temp%\nsi2.tmp\Base64.dll
  • %User Temp%\nsi2.tmp\ymsgr_suite_setup.exe
  • %User Temp%\nsi2.tmp\YExecShell.dll
  • %User Temp%\nsa4.tmp\System.dll
  • %User Temp%\nsa4.tmp\InetLoad_vms.dll
  • %User Temp%\nsa4.tmp\ymsgr11_us.ini
  • %User Temp%\nsa4.tmp\nsp5.tmp.htm
  • %User Temp%\nsa4.tmp\nsw6.tmp.htm
  • %User Temp%\nsa4.tmp\s1.bmp
  • %User Temp%\nsa4.tmp\s2.bmp
  • %User Temp%\nsa4.tmp\s3.bmp
  • %User Temp%\nsa4.tmp\s4.bmp
  • %User Temp%\nsa4.tmp\s5.bmp
  • %User Temp%\nsa4.tmp\ywiseextU.dll
  • %User Temp%\nsa4.tmp\eula.rtf
  • %User Temp%\nsa4.tmp\finish.ini
  • %User Temp%\nsa4.tmp\legal.ini
  • %User Temp%\nsa4.tmp\review.ini
  • %User Temp%\nsa4.tmp\software.ini
  • %User Temp%\nsa4.tmp\welcome.ini
  • %User Temp%\nsa4.tmp\modern-header.bmp
  • %User Temp%\nsa4.tmp\InstallOptions.dll
  • %User Temp%\nsa4.tmp\bb.html
  • %User Temp%\nsa4.tmp\stack.dll
  • %User Temp%\nsa4.tmp\ymsgr_inst.exe

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_VB.SMUS4. 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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