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Discovered: April 10, 2005
Updated: February 13, 2007 12:36:49 PM
Also Known As: Win32.Bropia.AB [Computer Asso, Win32.Kelvir.Q [Computer Assoc, IM-Worm.Win32.Kelvir.{g, h} [Kaspersky Lab], W32/Kelvir.worm.t [McAfee], W32/Kelvir-{H, L} [Sophos], WORM_KELVIR.{L, R} [Trend Micro]
Type: Worm
Systems Affected: Windows

W32.Kelvir.P is a worm that spreads through MSN Messenger and drops a variant of W32.Spybot.NLI.

Antivirus Protection Dates

  • Initial Rapid Release version April 11, 2005
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version April 11, 2005
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date April 13, 2005

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

Writeup By: Ka Chun Leung

Discovered: April 10, 2005
Updated: February 13, 2007 12:36:49 PM
Also Known As: Win32.Bropia.AB [Computer Asso, Win32.Kelvir.Q [Computer Assoc, IM-Worm.Win32.Kelvir.{g, h} [Kaspersky Lab], W32/Kelvir.worm.t [McAfee], W32/Kelvir-{H, L} [Sophos], WORM_KELVIR.{L, R} [Trend Micro]
Type: Worm
Systems Affected: Windows

When W32.Kelvir.P is executed, it performs the following actions:

  1. Sends one of the following messages to all the MSN Messenger contacts on the compromised computer:

    • Check this naked screensaver, wow, it's so cool!!
    • Look what my dad gave me!!
    • This guy has one big cock, lol!
    • Wow, what a chick, she is so beautiful
    • Check me, i made this, very easy haha!
    • huhuhu vinger in die poepert

      followed by one of the following links:

    • [domain removed].com/4uqjx
    • [domain removed].com/6qqmv
    • [domain removed].com/5q2c2
    • [domain removed].com/5f49e
    • [domain removed].com/6o2e

      Note: A recipient must click on the link and download and execute a file named Screensaver.scr. The file is a copy of the worm. It is a self-extracting rar file.

  2. Downloads a file from http://[domain removed]/~wxwarez/test/Service.exe and saves it as to C:\Service.exe. This is a copy of W32.Spybot.NLI.

  3. Adds the value:

    "Windows Screensaver" = "%Windows%\Service.exe"

    to the registry subkeys:


    so that the W32.Spybot.NLI runs every time Windows starts.

  4. Ends the following services, some of which may be security-related:

    • SharedAccess
    • Event Log
    • Zonealarm
    • TrueVector Internet Monitor
    • Norton AntiVirus Client
    • Norton Antivirus Auto Protect Service
    • Norton Internet Security Accounts Manager
    • Norton Internet Security Proxy Service
    • Norton Internet Security Service
    • Norton AntiVirus ServerNorton AntiVirus Auto Protect Service
    • CFINET32
    • Symantec AntiVirus Client
    • McShield
    • IPSEC Policy Agent
    • DefWatch
    • WMDM PMSP Service
    • Symantec Proxy Service
    • Symantec Event Manager
    • Norton AntiVirus Corporate Edition
    • ViRobot Professional Monitoring
    • AVP.EXE
    • ViRobot Expert Monitoring
    • savroam
    • symantec antivirus
    • ViRobot Lite Monitoring
    • PC-cillin Personal Firewall
    • Trend Micro Proxy Service
    • Trend NT Realtime Service
    • McAfee.com McShield
    • eTrust Antivirus Realtime Server
    • McAfee.com VirusScan Online Realtime Engine
    • McAfee Agent
    • SyGateService
    • Sygate Personal Firewall Pro
    • Sophos Anti-Virus
    • Sophos Anti-Virus Network
    • Ahnlab Task Scheduler
    • eTrust Antivirus Job Server
    • LOCKDOWN2000
    • ICMON
    • eTrust Antivirus RPC Server
    • V3MonNT
    • V3MonSvc
    • Quick Heal Online Protection
    • Kaspersky
    • Kaspersky Anti-Virus
    • Kaspersky Antivirus
    • Kaspersky Client
    • kaspersky auto protect service
    • kav
    • AVG6 Service
    • AVP32
    • MCAFEE
    • NORTON
    • NVC95
    • FP-WIN
    • IOMON98
    • PCCWIN98
    • F-PROT95
    • F-STOPW
    • PVIEW95
    • NAVWNT
    • NAVLU32
    • RESCUE32
    • ATRACK
    • IAMAPP
    • LUALL
    • NMAIN
    • NAVW32
    • NAVAPW32
    • VSSTAT
    • VSHWIN32
    • POP3TRAP
    • MonSvcNT
    • rising process communication center
    • rising realtime monitor service
    • OfficeScanNT Monitor
    • RemoteAgent
    • Panda Antivirus
    • ZoneAlarm
    • Detector de OfficeScanNT
    • Norton Internet Security Proxy Srvice
    • Norton Internet Security service
    • Sygate Personal Firewall
    • Security Center
    • Windows Firewall
    • Windows Internet Connection Sharing(ICS)
    • NAV Alert
    • NAV Auto-Protect
    • ScriptBlocking Service
    • Background Intelligent Transfer Service
    • System Event Notification
    • BlackICE
    • FireBall
    • AVSync Manager
    • officescannt realtime scan
    • officescannt listener
    • services32 service: msinit
    • msinit
    • AVP control center service
    • KAV Moniter Service
    • P2P Networking
    • gear security
    • MastDLL
    • MsInt
    • MsIntScan
    • FireBaum
    • Eventask
    • InternetFirewallProc
    • Serv-U
    • mcafee framework service
    • task manager
    • mcshield
    • config loader
    • iroff
    • servu
    • secur2
    • avast! iavs4 control service
    • avast! antivirus
    • internet pr0tocol
    • fix-it task manager
    • dllhost
    • dns
    • fxsvc
    • nvscv
    • outpost firewall service
    • scvhost
    • syslock
    • snake sockproxy service
    • msclol2
    • msclol8
    • systemsecuritydll
    • vnc server
    • intel pds
    • intel file transfer
    • smss
    • rundll
    • serv-u-ftp
    • Norton Unerase Protection
    • AVG7 Alert Manager Server
    • AVG7 Update Service
    • kerio personal firewall
    • Rising Process Communication Center
    • Rising Realtime Monitor Service
    • Kingsoft AntiVirus Service
    • VNC server
    • Internet Connection Firewall (ICF) / Internet Connection Sharing (ICS)
    • symantec central quarantine
    • symantec quarantine agent
    • symantec quarantine scanner
    • psexesvc
    • etrust antivirus rpc server
    • etrust antivirus realtime server
    • etrust antivirus job server
    • remotely possible/32
    • win32sl
    • altiris client service
    • pcanywhere host service
    • carbon copy access edition
    • directupdate engine
    • noipducservice


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: Ka Chun Leung

Discovered: April 10, 2005
Updated: February 13, 2007 12:36:49 PM
Also Known As: Win32.Bropia.AB [Computer Asso, Win32.Kelvir.Q [Computer Assoc, IM-Worm.Win32.Kelvir.{g, h} [Kaspersky Lab], W32/Kelvir.worm.t [McAfee], W32/Kelvir-{H, L} [Sophos], WORM_KELVIR.{L, R} [Trend Micro]
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. Update the virus definitions.
  3. Run a full system scan and delete all the files detected as W32.Kelvir.P.
  4. Delete the value that was added to the registry.
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:
When you are completely finished with the removal procedure and are satisfied that the threat has been removed, re-enable 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 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: These virus definitions are posted to the LiveUpdate servers once each week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, refer to the Virus Definitions (LiveUpdate).
  • 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 the Virus Definitions (Intelligent Updater).

    The Intelligent Updater virus definitions are available: Read: How to update virus definition files using the Intelligent Updater, for detailed instructions.

3. 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 as infected with W32.Kelvir.P, click Delete.

    If your Symantec antivirus product reports that it cannot delete an infected file, Windows may be using the file. To fix 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 section 4.
4. 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. Read the document: How to make a backup of the Windows registry , for instructions.
  1. Click Start > Run.

  2. Type regedit

    Then click OK.

  3. Navigate to the subkeys:


  4. In the right pane, delete the value:

    "Windows Screensaver" = "%Windows%\Service.exe"

  5. Exit the Registry Editor.

Writeup By: Ka Chun Leung