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21 June 2007
Risk Impact:
Systems Affected:


Adware.PurityScan is an adware program that downloads and displays advertisements on a computer.

Note: Definitions prior to April 6, 2005 may detect this security risk as Adware.Purityscan.B, Adware.Purityscan.C, or Adware.Purityscan.D.

Antivirus Protection Dates

  • Initial Rapid Release version 02 October 2014 revision 022
  • Latest Rapid Release version 17 August 2019 revision 016
  • Initial Daily Certified version 05 September 2003 revision 041
  • Latest Daily Certified version 08 August 2019 revision 001
  • Initial Weekly Certified release date 10 September 2003
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
Due to the self-updating nature of Adware.PurityScan, this information is liable to change as new versions of the Adware are published.

When Adware.PurityScan is executed, it adds itself to the following location:
%UserProfile%\Start Menu\Programs\Purity Scan

Next, the program may create the following files (possibly with the first and/or second letters replaced with a question mark):
  • %System%\wnsinttr.exe
  • %System%\wnscpit.exe
  • %System%\Microsoft.NET.exe
  • %System%\Drivers.exe
  • %System%\WinSxS.exe
  • %System%\Tasks.exe
  • %System%\system32.exe
  • %System%\system.exe
  • %System%\symbols.exe
  • %System%\security.exe
  • %System%\java.exe
  • %System%\Help.exe
  • %System%\Fonts.exe
  • %System%\assembly.exe
  • %System%\AppPatch.exe
  • %System%\regsvr32.exe
  • %System%\regedit.exe
  • %System%\tracert.exe
  • %System%\nslookup.exe
  • %System%\arpa.exe
  • %System%\ping.exe
  • %System%\mshta.exe
  • %System%\nopdb.exe
  • %System%\winword.exe
  • %System%\ati2evxx.exe
  • %System%\spool32.exe
  • %System%\msconfig.exe
  • %System%\userinit.exe
  • %System%\netdde.exe
  • %System%\mmc.exe
  • %System%\scanregw.exe
  • %System%\wucrtupd.exe
  • %System%\wuauboot.exe
  • %System%\wuauclt.exe
  • %System%\wuaclt.exe
  • %System%\rundll.exe
  • %System%\fast.exe
  • %System%\alg.exe
  • %System%\cmd.exe
  • %System%\dexplore.exe
  • %System%\iexplore.exe
  • %System%\notepad.exe
  • %System%\msdtc.exe
  • %System%\javaw.exe
  • %System%\ntvdm.exe
  • %System%\wowexec.exe
  • %System%\winspool.exe
  • %System%\taskmgr.exe
  • %System%\rundll32.exe
  • %System%\msiexec.exe
  • %System%\logonui.exe
  • %System%\dvdplay.exe
  • %System%\dllhost.exe
  • %System%\chkdsk.exe
  • %System%\chkntfs.exe
  • %System%\attrib.exe
  • %System%\winlogon.exe
  • %System%\spoolsv.exe
  • %System%\smss.exe
  • %System%\services.exe
  • %System%\lsass.exe
  • %System%\csrss.exe
  • %System%\svchost.exe
  • %System%\explorer.exe

Next, the program may create one or more of the following registry entries so that it executes whenever Windows starts:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"Content Service" = %System%\winserv[LETTER].exe
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"twhe" = %Windir%\Application Data\wbta.exe
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"Ussi" = %Windir%\Application Data\rwsa.exe
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"Ussi" = "%System%\wnscpit.exe"
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"Oesi" = "%SystemDrive%\Documents and Settings\[USER NAME]\Application Data\srts.exe"
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"Eech" = "%SystemDrive%\Documents and Settings\[USER NAME]\Application Data\hoor.exe"
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"WNSI" = "%SystemDrive%\Documents and Settings\[USER NAME]\Application Data\rwsa.exe"
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"Esph" = "%SystemDrive%\Documents and Settings\[USER NAME]\Application Data\ortu.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"Content Service" = %System%\winserv[LETTER].exe
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"twhe" = %Windir%\Application Data\wbta.exe
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"Ussi" = %Windir%\Application Data\rwsa.exe
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"Ussi" = "%System%\wnscpit.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"Oesi" = "%SystemDrive%\Documents and Settings\[USER NAME]\Application Data\srts.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"Eech" = "%SystemDrive%\Documents and Settings\[USER NAME]\Application Data\hoor.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"WNSI" = "%SystemDrive%\Documents and Settings\[USER NAME]\Application Data\rwsa.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"Esph" = "%SystemDrive%\Documents and Settings\[USER NAME]\Application Data\ortu.exe"

In the above registry entries, [LETTER] is a variable letter that will change for different versions of PuritySCAN. Samples we have seen will generally delete the old version before installing the updated one.

The program then creates the following registry subkeys:

It may then creates some or all of the following files:
  • %Program Files%\PurityScan\PuritySCAN.exe
  • %ProgramFiles%\PurityScan\PuritySCANUninstall.exe
  • %System%\Winserv[LETTER].exe
  • %System%\Winservn.exeps_uninstaller.exe
  • %CurrentFolder%\Rs.exe
  • %Windir%\Application\Data\Wbta.exe
  • %SystemDrive%\Documents and Settings\[USER NAME]\Application Data\srts.exe
  • %SystemDrive%\Documents and Settings\[USER NAME]\Application Data\hoor.exe
  • %SystemDrive%\Documents and Settings\[USER NAME]\Application Data\rbap.exe
  • %SystemDrive%\Documents and Settings\[USER NAME]\Application Data\rwsa.exe

The program may create the following folder:
%UserProfile%\Application Data\ilas

It then creates a shortcut to the risk on the desktop.

Next, the program contacts a remote server on the domain. The adware then registers system information and the status of the installation with the server and checks for software updates to install.

It also scans Internet Explorer files, including browser files, cache, history, and cookies for adult-related keywords. It then displays advertisements.

The program downloads and displays advertisements from Web sites on the following domains:

You may have arrived at this page either because you have been alerted by your Symantec product about this risk, or you are concerned that your computer has been affected by this risk.

Before proceeding further we recommend that you run a full system scan . If that does not resolve the problem you can try one of the options available below.

If you are a Norton product user, we recommend you try the following resources to remove this risk.

Removal Tool

If you have an infected Windows system file, you may need to replace them using from the Windows installation CD .

How to reduce the risk of infection
The following resources provide further information and best practices to help reduce the risk of infection.

If you are a Symantec business product user, we recommend you try the following resources to remove this risk.

Identifying and submitting suspect files
Submitting suspicious files to Symantec allows us to ensure that our protection capabilities keep up with the ever-changing threat landscape. Submitted files are analyzed by Symantec Security Response and, where necessary, updated definitions are immediately distributed through LiveUpdate™ to all Symantec end points. This ensures that other computers nearby are protected from attack. The following resources may help in identifying suspicious files for submission to Symantec.

Removal Tool

If you have an infected Windows system file, you may need to replace them using from the Windows installation CD .

How to reduce the risk of infection
The following resource provides further information and best practices to help reduce the risk of infection.
Protecting your business network

The following instructions pertain to all current Symantec antivirus products.

1. Performing a full system scan
How to run a full system scan using your Symantec product

2. Restoring settings in the registry
Many risks make modifications to the registry, which could impact the functionality or performance of the compromised computer. While many of these modifications can be restored through various Windows components, it may be necessary to edit the registry. See in the Technical Details of this writeup for information about which registry keys were created or modified. Delete registry subkeys and entries created by the risk and return all modified registry entries to their previous values.