W32.Sygyp.A@mm

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Discovered: January 21, 2006
Updated: February 13, 2007 12:50:44 PM
Type: Worm
Systems Affected: Windows


W32.Sygyp.A@mm is a mass-mailing worm that also spreads through file-sharing networks and lowers security settings on the compromised computer.

Antivirus Protection Dates

  • Initial Rapid Release version January 22, 2006
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version January 22, 2006
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date January 25, 2006

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Writeup By: Hyun Choi

Discovered: January 21, 2006
Updated: February 13, 2007 12:50:44 PM
Type: Worm
Systems Affected: Windows


When W32.Sygyp.A@mm is executed, it performs the following actions:

  1. Copies itself as the following files:

    • %System%\Regverif32.exe
    • %Windir%\GoogleEarthSetup.exe

      Note:
    • %System% is a variable that refers to the System folder. By default this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).
    • %Windir% is a variable that refers to the Windows installation folder. By default, this is C:\Windows (Windows 95/98/Me/XP) or C:\Winnt (Windows NT/2000).

  2. Creates the following files:

    • %System%\Sys32.reg
    • %System%\Reg32.reg
    • %System%\OE32.reg
    • %System%\Sec32.reg
    • %System%\FWall32.reg
    • %System%\NTFS32.reg
    • %System%\W32Info.reg

  3. Adds the value:

    "RegVfy32" = "%System%\Regverif32.exe"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

    so that the worm runs every time Windows starts.

  4. Adds the values:

    "DisableTaskmgr" = "1"
    "DisableRegistryTools" = "1"

    to the registry subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System

    to disable the Registry Editor and the Task Manager.

  5. Adds the values:

    "Compact Do not Ask Again" = "1"
    "Delete Thread Warning" = "6"
    "Mail Empty Subject Warning" = "1"
    "Send Mail Warning" = "1"

    to the registry subkey:

    HKEY_CURRENT_USER\Identities\[DEFAULT USER]\Software\Microsoft\Outlook Express\[OUTLOOK VERSION]\Dont Show Dialogs

    to prevent certain warning messages from being displayed by Microsoft Outlook.

  6. Adds the values:

    "AntiVirusDisableNotify" = "0"
    "AntiVirusOverride" = "0"
    "FirewallDisableNotify" = "0"
    "FirewallOverride" = "0"
    "UpdatesDisableNotify" = "0"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center

    to lower security settings and disable the Windows Security Center.

  7. Adds the value:

    "EnableFirewall" = "0"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess
    \Parameters\FirewallPolicy\StandardProfile

    to disable the Windows firewall.

  8. Adds the values:

    "limitblankpassworduse" = "0"
    "forceguest" = "0"
    "crashonauditfail" = "0"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\LSA

    to modify file sharing settings.

  9. Adds the values:

    "Virus Name" = "W32.Gypsy@mm"
    "Virus Creator" = "Unknowan"
    "Virus Origin" = "Unknowan"
    "Virus Type" = "Worm"
    "Virus Path" = "%System%"
    "Virus Created With" = "Visual Basic 6"
    "Date Of Infection" = "[DATE]"
    "Time Of Infection" = "[TIME]"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Gypsy\W32.Gypsy\Virus Infomation

    to store information about the threat.

  10. On Windows NT, copies itself as the following files:

    • %ProgramFiles%\WindowsUpdate\System Security\Asistant_Alert.exe
    • %ProgramFiles%\WindowsUpdate\System Security\NetAlert_v2.4.exe
    • %ProgramFiles%\WindowsUpdate\System Security\Updates.tmp\exploit_patcher_v1.0.0.exe
    • %ProgramFiles%\WindowsUpdate\System Security\Updates.tmp\NetWatch_v1.0.3.exe

      Note: %ProgramFiles% is a variable that refers to the program files folder. By default, this is C:\Program Files.

  11. On Windows NT, shares the following folders:

    • Remote Service=%ProgramFiles%\WindowsUpdate
    • Gypsy=%SystemDrive%
    • ADMIN$

      Note: %SystemDrive% is a variable that refers to the drive on which Windows is installed. By default, this is drive C.

  12. On Windows NT, adds the following lines to %System%\drivers\etc\hosts:

    # Host file has been infected by :
    # W32.Gypsy@mm

    127.0.0.1 www.google.com
    127.0.0.1 www.yahoo.com
    127.0.0.1 www.hotmail.com
    127.0.0.1 www.microsoft.com
    127.0.0.1 www.symantec.com
    127.0.0.1 www.trendmicro.com
    127.0.0.1 www.mcafee.com
    127.0.0.1 messenger.yahoo.com
    127.0.0.1 messenger.msn.com
    127.0.0.1 www.kazaa.com
    127.0.0.1 www.emule.com
    127.0.0.1 www.winmx.com
    127.0.0.1 www.limewire.com
    127.0.0.1 www.winguides.com
    127.0.0.1 www.vet.com
    127.0.0.1 www.ebay.com
    127.0.0.1 www.msn.com
    127.0.0.1 www.hotmail.com
    127.0.0.1 www.mp3.com
    127.0.0.1 www.grisoft.com
    127.0.0.1 www.zonelabs.com
    127.0.0.1 www.lavasoft.com
    127.0.0.1 update.microsoft.com
    127.0.0.1 morpheus.com
    127.0.0.1 www.imesh.com
    127.0.0.1 www.edonkey2000.com
    127.0.0.1 www.bearshare.com
    127.0.0.1 www.agsatellite.com
    127.0.0.1 www.zeropaid.com
    127.0.0.1 www.bittorrent.com
    127.0.0.1 login.yahoo.com
    127.0.0.1 www.securityfocus.com
    127.0.0.1 www.geocities.com
    127.0.0.1 www.sophos.com
    127.0.0.1 www.pandasoftware.com
    127.0.0.1 www.ibm.com
    127.0.0.1 www.dell.com
    127.0.0.1 www.hp.com
    127.0.0.1 www.sec-1.com
    127.0.0.1 www.kaspersky.com

  13. Stops the following security-related processes:

    • avgctrl.exe
    • kav.exe
    • avgamsvr.exe
    • avgserv.exe
    • avgmsvr.exe
    • avgcc32.exe
    • avgcc.exe
    • avginet.exe
    • avgupsvc.exe
    • avgemc.exe
    • avgnt.exe
    • avgregcl.exe
    • avgserv9.exe
    • avgw.exe
    • alogserv.exe
    • avsynmgr.exe
    • Mpfsheild.exe
    • doc
    • MpfAgent.exe
    • mpf.exe
    • MpfConsole.exe
    • mcagent.exe
    • mcappins.exe
    • McDash.exe
    • mcdetect.exe
    • mcinfo.exe
    • mcmnhdlr.exe
    • mcshield.exe
    • mctskshd.exe
    • mcupdate.exe
    • mcvsescn.exe
    • mcvsshld.exe
    • avpcc.exe
    • mcvsftsn.exe
    • mcvsrte.exe
    • vstskmgr.exe
    • vsmain.exe
    • vshwin32.exe
    • pccpfw.exe
    • pccclient.exe
    • pcclient.exe
    • pccguide.exe
    • pccnt.exe
    • pccntmon.exe
    • pccntupd.exe
    • PcCtlCom.exe
    • pcscan.exe
    • avpm.exe
    • kavmm.exe
    • kavsvc.exe
    • AVENGINE.EXE
    • remupd.exe
    • inicio.exe
    • prevsrv.exe
    • ALsvc.exe
    • ALMon.exe
    • SavService.exe
    • SWNETSUP.exe
    • ALUNotify.exe
    • ccApp.exe
    • nisserv.exe
    • NISUM.exe
    • Navapsvc.exe
    • NMain.exe
    • Navapw32.exe
    • VetMsg.exe
    • VetTray.exe
    • Vet32.exe
    • VetNT.exe
    • vsmon.exe
    • zlclient.exe
    • zapro.exe
    • zonealarm.exe

  14. Harvests email addresses by searching through files with the following extensions:

    • .htm
    • .php
    • .hta
    • .doc
    • .hte
    • .php
    • .htt
    • .xls
    • .htx
    • .eml
    • .sht
    • .jsp
    • .stm
    • .xml
    • .js
    • .cgi
    • .vbs
    • .vbe

  15. Sends emails to the harvested email addresses using Outlook Express. The emails have the following characteristics:

    Subject:
    Google Earth – Explore, Search and Discover

    Message body:
    Want to know more about a specific location? Dive right in -- Google Earth combines satellite
    imagery, maps and the power of Google Search to put the world's geographic information at your
    fingertips.

    * Fly from space to your neighborhood. Type in an address and zoom right in.
    * Search for schools, parks, restaurants, and hotels. Get driving directions.
    * Tilt and rotate the view to see 3D terrain and buildings.
    * Save and share your searches and favorites. Even add your own annotations.

    Attachment:
    GoogleEarthSetup.exe

  16. On Windows NT, deletes all scheduled tasks.

  17. On Windows NT, adds the following task to be performed everyday at the same time as the execution of the worm:

    Shutdown -S -T10 -C "From state to state and city to city infecting computers like a wondering Gypsy..!!"

  18. Displays the following error message:

    The file [WORM FILE NAME] is corrupted or missing


Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
  • Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
  • Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.

Writeup By: Hyun Choi

Discovered: January 21, 2006
Updated: February 13, 2007 12:50:44 PM
Type: Worm
Systems Affected: Windows


The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

  1. Disable System Restore (Windows Me/XP).
  2. Remove all the entries that the risk added to the hosts file.
  3. Update the virus definitions.
  4. Run a full system scan and delete all the files detected.
  5. Delete any values added to the registry.
  6. Restore the Windows Security Center.
  7. Reenable the SharedAccess service (Windows 2000/XP only).
For specific details on each of these steps, read the following instructions.

1. To disable System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:
Note:
When you are completely finished with the removal procedure and are satisfied that the threat has been removed, reenable System Restore by following the instructions in the aforementioned documents.

For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article: Antivirus Tools Cannot Clean Infected Files in the _Restore Folder (Article ID: Q263455).

2. To remove all the entries that the risk added to the hosts file
  1. Navigate to the following location:

    • Windows 95/98/Me:
      %Windir%
    • Windows NT/2000/XP:
      %Windir%\System32\drivers\etc

      Notes:
    • The location of the hosts file may vary and some computers may not have this file. There may also be multiple copies of this file in different locations. If the file is not located in these folders, search your disk drives for the hosts file, and then complete the following steps for each instance found.
    • %Windir% is a variable that refers to the Windows installation folder. By default, this is C:\Windows (Windows 95/98/Me/XP) or C:\Winnt (Windows NT/2000).

  2. Double-click the hosts file.
  3. If necessary, deselect the "Always use this program to open this program" check box.
  4. Scroll through the list of programs and double-click Notepad.
  5. When the file opens, delete all the entries added by the risk. (See the Technical Details section for a complete list of entries.)
  6. Close Notepad and save your changes when prompted.

3. To update the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:
  • Running LiveUpdate, which is the easiest way to obtain virus definitions:
    • If you use Norton AntiVirus 2006, Symantec AntiVirus Corporate Edition 10.0, or newer products, LiveUpdate definitions are updated daily. These products include newer technology.
    • If you use Norton AntiVirus 2005, Symantec AntiVirus Corporate Edition 9.0, or earlier products, LiveUpdate definitions are updated weekly. The exception is major outbreaks, when definitions are updated more often.
  • Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted daily. You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to Virus Definitions (Intelligent Updater).

    The latest Intelligent Updater virus definitions can be obtained here: Intelligent Updater virus definitions. For detailed instructions read the document: How to update virus definition files using the Intelligent Updater.

4. To scan for and delete the infected files
  1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.
  2. Run a full system scan.
  3. If any files are detected, click Delete.

Important: If you are unable to start your Symantec antivirus product or the product reports that it cannot delete a detected file, you may need to stop the risk from running in order to remove it. To do this, run the scan in Safe mode. For instructions, read the document, How to start the computer in Safe Mode . Once you have restarted in Safe mode, run the scan again.

After the files are deleted, restart the computer in Normal mode and proceed with the next section.

Warning messages may be displayed when the computer is restarted, since the threat may not be fully removed at this point. You can ignore these messages and click OK. These messages will not appear when the computer is restarted after the removal instructions have been fully completed. The messages displayed may be similar to the following:

Title: [FILE PATH]
Message body: Windows cannot find [FILE NAME]. Make sure you typed the name correctly, and then try again. To search for a file, click the Start button, and then click Search.

5. To delete the value from the registry
Important: Symantec strongly recommends that you back up the registry before making any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified subkeys only. For instructions refer to the document: How to make a backup of the Windows registry.
  1. Click Start > Run.
  2. Type regedit
  3. Click OK.

    Note: If the registry editor fails to open the threat may have modified the registry to prevent access to the registry editor. Security Response has developed a tool to resolve this problem. Download and run this tool, and then continue with the removal.

  4. Navigate to the subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

  5. In the right pane, delete the value:

    "RegVfy32" = "%System%\Regverif32.exe"

  6. Navigate to and delete the subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Gypsy\W32.Gypsy

  7. Navigate to the subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System

  8. In the right pane, reset the value:

    "DisableTaskmgr" = "1"

  9. Navigate to the subkey:

    HKEY_CURRENT_USER\Identities\[DEFAULT USER]\Software\Microsoft\Outlook Express\[OUTLOOK VERSION]\Dont Show Dialogs

  10. In the right pane, reset the values:

    "Compact Do not Ask Again" = "1"
    "Delete Thread Warning" = "6"
    "Mail Empty Subject Warning" = "1"
    "Send Mail Warning" = "1"

  11. Navigate to the subkey:

    HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\LSA

  12. In the right pane, reset the values:

    "limitblankpassworduse" = "0"
    "forceguest" = "0"
    "crashonauditfail" = "0"

  13. Exit the Registry Editor.

6. To restore the Windows Security Center
This risk attempts to disable the features in the Windows Security Center, available in Windows XP Service Pack 2. If you are running Windows XP Service Pack 2 and would like to restore the full functionality of the Windows Security Center, please complete the following steps:

Important: If your computer is connected to a domain, you may not be able to adjust these settings. If so, contact your network administrator for more information.
  1. Click Start > Control Panel.
  2. Double-click the Security Center.
  3. In the right pane, click Windows Firewall. The Windows Firewall appears.
  4. Select On.
  5. Click OK to close the Windows Firewall.
  6. In the left pane of the Security Center, select Change the way Security Center alerts me.
  7. Click Alert Settings.
  8. Select Alert Settings, Firewall, and Virus Protection.
  9. Click OK
  10. Click Automatic Updates.
  11. Select Automatic.
  12. Click OK.
  13. Exit the Security Center.

7. To reenable the SharedAccess service (Windows 2000/XP only)
The SharedAccess service is responsible for maintaining Internet Connection Sharing and the Windows Firewall/Internet Connection Firewall applications in Windows. (The presence and names of these applications vary depending on the operating system and service pack you are using.) To protect your computer and maintain network functionality, re-enable this service if you are using any of these programs.


Windows XP Service Pack 2
If you are running Windows XP with Service Pack 2 and are using the Windows Firewall, the operating system will alert you when the SharedAccess service is stopped, by displaying an alert balloon saying that your Firewall status is unknown. Perform the following steps to ensure that the Windows Firewall is re-enabled:
  1. Click Start > Control Panel.

  2. Double-click the Security Center.

  3. Ensure that the Firewall security essential is marked ON.

    Note: If the Firewall security essential is marked on, your Windows Firewall is on and you do not need to continue with these steps.

    If the Firewall security essential is not marked on, click the "Recommendations" button.

  4. Under "Recommendations," click Enable Now. A window appears telling you that the Windows Firewall was successfully turned on.

  5. Click Close, and then click OK.

  6. Close the Security Center.


Windows 2000 or Windows XP Service Pack 1 or earlier
Complete the following steps to re-enable the SharedAccess service:
  1. Click Start > Run.
  2. Type services.msc

    Then click OK.

  3. Do one of the following:
    • Windows 2000: Under the Name column, locate the "Internet Connection Sharing (ICS)" service and double-click it.
    • Windows XP: Under the Named column, locate the "Internet Connection Firewall (ICF) / Internet Connection Sharing (ICS)" service and double-click it.

  4. Under "Startup Type:", select "Automatic" from the drop-down menu.

  5. Under "Service Status:", click the Start button.

  6. Once the service has completed starting, click OK.

  7. Close the Services window.


Writeup By: Hyun Choi