ALIASES:

PUA.Downloader (Symantec)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:
 SYSTEM IMPACT RATING:
 INFORMATION EXPOSURE:

  • Threat Type: Adware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This adware 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: 105,792 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 20 Jan 2015

Arrival Details

This adware 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 adware creates the following folders:

  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\Wilbert
  • %User Profile%\LOCALS~1
  • %User Temp%\nsy6.tmp
  • %Program Files%\STab
  • %Program Files%\STab\skin
  • %Program Files%\STab\skin\image
  • %User Profile%\Application Data\IHProtectUpDate
  • %User Profile%\IHProtectUpDate\update

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %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.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

Other System Modifications

This adware deletes the following files:

  • %User Temp%\nsy4.tmp
  • %User Temp%\nsy6.tmp

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\SupDp

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Uninstall\
STab

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\SearchScopes

HKEY_LOCAL_MACHINE\SOFTWARE\IHProtect

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\SupDp
dir = "%Program Files%\STab"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
STab
UninstallString = "%Program Files%\STab\uninstall.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
STab
DisplayName = "STab"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
STab
DisplayIcon = "%Program Files%\STab\STab"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
STab
DisplayVersion = "4.0.1.1251"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Default_Page_URL = "http://www.{BLOCKED}9.com/?type=hppp"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Default_Search_URL = "http://www.{BLOCKED}9.com/web/?type=dspp&q={searchTerms}"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Start Page = "http://www.{BLOCKED}9.com/?type=hppp"

(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}9.com/?type=hppp"

(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_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Start Page = "http://www.{BLOCKED}9.com/?type=hppp"

(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\Search
CustomizeSearch = "http://www.{BLOCKED}9.com/web/?type=dspp&q={searchTerms}"

(Note: The default value data of the said registry entry is http://ie.search.msn.com/{SUB_RFC1766}/srchasst/srchcust.htm.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Search
SearchAssistant = "http://www.{BLOCKED}9.com/web/?type=dspp&q={searchTerms}"

(Note: The default value data of the said registry entry is http://ie.search.msn.com/{SUB_RFC1766}/srchasst/srchasst.htm.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Search Page = "http://www.{BLOCKED}9.com/web/?type=dspp&q={searchTerms}"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Default_Search_URL = "http://www.{BLOCKED}9.com/web/?type=dspp&q={searchTerms}"

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

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Search Page = "http://www.{BLOCKED}9.com/web/?type=dspp&q={searchTerms}"

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

Dropping Routine

This adware drops the following files:

  • %System Root%\STab_v4.0.exe
  • %User Temp%\nsy6.tmp\System.dll
  • %User Temp%\nsy6.tmp\modern-header.bmp
  • %Program Files%\STab\BrowerWatchCH.dll
  • %Program Files%\STab\BrowerWatchFF.dll
  • %Program Files%\STab\BrowserAction.dll
  • %Program Files%\STab\CmdShell.exe
  • %Program Files%\STab\HPNotify.exe
  • %Program Files%\STab\IeWatchDog.dll
  • %Program Files%\STab\ProtectService.exe
  • %Program Files%\STab\conf
  • %Program Files%\STab\msvcp110.dll
  • %Program Files%\STab\msvcr110.dll
  • %Program Files%\STab\skin\about.png
  • %Program Files%\STab\skin\about_bk.png
  • %Program Files%\STab\skin\btn.png
  • %Program Files%\STab\skin\btn_apply.png
  • %Program Files%\STab\skin\close.png
  • %Program Files%\STab\skin\conf.xml
  • %Program Files%\STab\skin\conf_back.png
  • %Program Files%\STab\skin\input_bk.png
  • %Program Files%\STab\skin\logo.png
  • %Program Files%\STab\skin\main.xml
  • %Program Files%\STab\skin\radio_1.png
  • %Program Files%\STab\skin\radio_2.png
  • %Program Files%\STab\skin\rigth_arrow.png
  • %Program Files%\STab\skin\settings.png
  • %Program Files%\STab\uninstall.exe

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

Other Details

This adware connects to the following possibly malicious URL:

  • http://www.{BLOCKED}z.cc/{random path}
  • {BLOCKED}209.234
  • {BLOCKED}.35.142

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.700

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_LOCAL_MACHINE\Software
    • SupDp
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall
    • STab
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer
    • SearchScopes
  • In HKEY_LOCAL_MACHINE\SOFTWARE
    • IHProtect

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_LOCAL_MACHINE\SOFTWARE\SupDp
    • dir = "%Program Files%\STab"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\STab
    • UninstallString = "%Program Files%\STab\uninstall.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\STab
    • DisplayName = "STab"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\STab
    • DisplayIcon = "%Program Files%\STab\STab"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\STab
    • DisplayVersion = "4.0.1.1251"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • Default_Page_URL = "http://www.{BLOCKED}9.com/?type=hppp"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • Default_Search_URL = "http://www.{BLOCKED}9.com/web/?type=dspp&q={searchTerms}"

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\Internet Explorer\Main
    • From: Start Page = "http://www.{BLOCKED}9.com/?type=hppp"
      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}9.com/?type=hppp"
      To: Default_Page_URL = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome""
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • From: Start Page = "http://www.{BLOCKED}9.com/?type=hppp"
      To: Start Page = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Search
    • From: CustomizeSearch = "http://www.{BLOCKED}9.com/web/?type=dspp&q={searchTerms}"
      To: CustomizeSearch = ""http://ie.search.msn.com/{SUB_RFC1766}/srchasst/srchcust.htm""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Search
    • From: SearchAssistant = "http://www.{BLOCKED}9.com/web/?type=dspp&q={searchTerms}"
      To: SearchAssistant = ""http://ie.search.msn.com/{SUB_RFC1766}/srchasst/srchasst.htm""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
    • From: Search Page = "http://www.{BLOCKED}9.com/web/?type=dspp&q={searchTerms}"
      To: Search Page = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
    • From: Default_Search_URL = "http://www.{BLOCKED}9.com/web/?type=dspp&q={searchTerms}"
      To: Default_Search_URL = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch""
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • From: Search Page = "http://www.{BLOCKED}9.com/web/?type=dspp&q={searchTerms}"
      To: Search Page = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch""

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 Root%\STab_v4.0.exe
  • %User Temp%\nsy6.tmp\System.dll
  • %User Temp%\nsy6.tmp\modern-header.bmp
  • %Program Files%\STab\BrowerWatchCH.dll
  • %Program Files%\STab\BrowerWatchFF.dll
  • %Program Files%\STab\BrowserAction.dll
  • %Program Files%\STab\CmdShell.exe
  • %Program Files%\STab\HPNotify.exe
  • %Program Files%\STab\IeWatchDog.dll
  • %Program Files%\STab\ProtectService.exe
  • %Program Files%\STab\conf
  • %Program Files%\STab\msvcp110.dll
  • %Program Files%\STab\msvcr110.dll
  • %Program Files%\STab\skin\about.png
  • %Program Files%\STab\skin\about_bk.png
  • %Program Files%\STab\skin\btn.png
  • %Program Files%\STab\skin\btn_apply.png
  • %Program Files%\STab\skin\close.png
  • %Program Files%\STab\skin\conf.xml
  • %Program Files%\STab\skin\conf_back.png
  • %Program Files%\STab\skin\input_bk.png
  • %Program Files%\STab\skin\logo.png
  • %Program Files%\STab\skin\main.xml
  • %Program Files%\STab\skin\radio_1.png
  • %Program Files%\STab\skin\radio_2.png
  • %Program Files%\STab\skin\rigth_arrow.png
  • %Program Files%\STab\skin\settings.png
  • %Program Files%\STab\uninstall.exe

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.
  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\Wilbert
  • %User Profile%\LOCALS~1
  • %User Temp%\nsy6.tmp
  • %Program Files%\STab
  • %Program Files%\STab\skin
  • %Program Files%\STab\skin\image
  • %User Profile%\Application Data\IHProtectUpDate
  • %User Profile%\IHProtectUpDate\update

Step 7

Scan your computer with your Trend Micro product to delete files detected as ADW_XTAB. 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 8

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.

  • %User Temp%\nsy4.tmp
  • %User Temp%\nsy6.tmp


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