Discovered: January 08, 2003
Updated: February 13, 2007 11:42:11 AM
Also Known As: Win32.Lirva.B [CA], W32/Avril-B [Sophos], WORM_LIRVA.C [Trend], I-Worm.Avron.b [KAV], W32/Lirva.c@MM [McAfee]
Type: Worm
Systems Affected: Windows
CVE References: CVE-2001-0154

NOTE: Due to a decreased rate of submissions, Symantec Security Response has downgraded this threat from a Category 3 to a Category 2 as of February 28, 2003.

W32.Lirva.C@mm is a mass-mailing worm that also spreads by IRC, ICQ, KaZaA, and open network shares. It is a variant of W32.Lirva.A@mm . This worm attempts to terminate antivirus and firewall products. It also emails the cached Windows 95/98/Me dial-up networking passwords to the virus writer.

The worm connects to a Web site on and downloads BackOrifice , which it executes. W32.Lirva.C@mm also attempts to download another file, which is currently not present on the Web site.

When Microsoft Outlook receives the worm, it takes advantage of a vulnerability that allows the attachment to auto-execute when you read or preview the email. Information on this vulnerability and a patch can be found at .

If the day of the month is the 7th, 11th, or 24th, the worm will launch your Web browser to and display a graphic animation on the Windows desktop.

As with many other worms, this worm takes advantage of a vulnerability that allows the attachment to auto-execute when you read or preview the email. Information on this vulnerability and a patch can be found at .

Antivirus Protection Dates

  • Initial Rapid Release version January 08, 2003
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version January 08, 2003
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date January 09, 2003

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

Technical Description

When W32.Lirva.C is executed, it does the following:

  1. Terminates all the processes with these names:
    • KPF.EXE
    • KPFW32.EXE
    • _AVPM.EXE
    • F-PROT.EXE
    • FP-WIN.EXE
    • N32SCAN.EXE
    • NAVW32.EXE
    • PCCWIN98.EXE
    • SCAN95.EXE
    • SMC.EXE
    • TCA.EXE
    • ACKWIN32.EXE
    • AVPDOS32.EXE
    • EFINET32.EXE
    • F-PROT95.EXE
    • IOMON98.EXE
    • NAVAPW32.EXE
    • TDS2-98.EXE
    • VSSCAN40.EXE
    • AVE32.EXE
    • AVP.EXE
    • AVPM.EXE
    • AVWIN95.EXE
    • CLAW95.EXE
    • DVP95.EXE
    • FRW.EXE
    • ICSUPP95.EXE
    • JED.EXE
    • NAVLU32.EXE
    • NVC95.EXE
    • SWEEP95.EXE
    • TDS2-NT.EXE
    • WFINDV32.EXE
    • _AVPCC.EXE
    • _AVP32.EXE
    • AVPTC32.EXE
    • AVWUPD32.EXE
    • CLAW95CT.EXE
    • DV95_O.EXE
    • DV95.EXE
    • F-AGNT95.EXE
    • ICLOAD95.EXE
    • LOCKDOWN2000.EXE
    • NAVW.EXE
    • RAV7.EXE
    • SCAN32.EXE
    • SERV95.EXE
    • VET95.EXE
    • VSHWIN32.EXE
    • AVP32.EXE
  2. Inventories all the windows and terminates any processes that have the following strings in the title bar of the window:
    • virus
    • anti
    • McAfee
    • Virus
    • Anti
    • AVP
    • Norton
  3. Copies itself as Hidden system files to:
    • %Temporary%\<random string>
    • %Temporary%\<random string>.tft
    • %System%\<random string>.exe
    • %All Drives%\Recycled\<random string>.exe
    • %Kazaa Downloads%\<random string>.exe
  4. Copies itself to various folders as a random file name.
  5. Creates these HTML files in the same folder as itself:
    • Index.html
    • Default.html
    • Index.htm
    • Default.htm

      and uses these files to execute the copies of itself, which it previously created.
  6. Adds the value:

    Avril Lavigne - Muse

    to the registry key:


    so that it runs when you start Windows.

    If the operating system is Windows NT/2000/XP, the worm will register itself as a service.
  7. Creates the registry key:

    HKEY_LOCAL_MACHINE\Software\OvG\Avril Lavigne

    and various subkeys that the worm uses to keep track of its infection process.
  8. Creates a non-malicious text file, %Temporary%\Avril-ii.inf, and other temporary files in the Windows Temporary folder.
  9. Checks whether the computer is currently connected to a network. If the worm is not connected, it will attempt to dial out using the default dial-up connection profile.
  10. Searches the Windows Address Book and files, with the extensions .dbx, .mbx, .wab, .html, .eml, .htm, .tbb, .shtml, .nch, and .idx, for the email addresses. Then, the worm sends the email messages with these characteristics:
    • Subject. The subject is one of the following:
      • Fw: Redirection error notification
      • Re: Brigada Ocho Free membership
      • Re: According to Purge's Statement
      • Fw: Avril Lavigne - CHART ATTACK!
      • Re: Reply on account for IIS-Security Breach (TFTP)
      • Re: ACTR/ACCELS Transcriptions
      • Re: IREX admits you to take in FSAU 2003
      • Fwd: Re: Have U requested Avril Lavigne bio?
      • Re: Reply on account for IFRAME-Security breach
      • Fwd: Re: Reply on account for Incorrect MIME-header
      • Re: Vote seniors masters - don't miss it!
      • Fwd: RFC-0245 Specification requested...
      • Fwd: RFC-0841 Specification requested...
      • Fw: F. M. Dostoyevsky "Crime and Punishment"
      • Re: Junior Achievement
      • Re: Ha perduto qualque cosa signora?
    • Message. The message is one of the following:
      • Network Associates weekly report: Microsoft has identified a security vulnerability in Microsoft IIS 4.0 and 5.0 that is eliminated by a previously-released patch. Customers who have applied that patch are already protected against the vulnerability and do not need to take additional action. to apply the patch immediately. Microsoft strongly urges all customers using IIS 4.0 and 5.0 who have not already done so Patch is also provided to subscribed list of Microsoft Tech Support: Patch: Date
      • Restricted area response team (RART) Attachment you sent to %s is intended to overwrite start address at 0000:HH4F To prevent from the further buffer overflow attacks apply the MSO-patch
      • Avril fans subscription FanList admits you to take in Avril Lavigne 2003 Billboard awards ceremony Vote for I'm with you! Admission form attached below
      • Chart attack active list: Vote fo4r I'm with you! Vote fo4r Sk8er Boi!Vote fo4r Complicated!AVRIL LAVIGNE - THE CHART ATTACK!
      • AVRIL LAVIGNE - THE BEST Avril Lavigne's popularity increases:> SO: First, Vote on TRL for I'm With U! Next, Update your pics database! Chart attack active list .>.>
      • Orginal Message:
    • Attachment. The attachment is one of the following:
      • Resume.exe
      • ADialer.exe
      • MSO-Patch-0071.exe
      • MSO-Patch-0035.exe
      • Two-Up-Secretly.exe
      • Transcripts.exe
      • Readme.exe
      • AvrilSmiles.exe
      • AvrilLavigne.exe
      • Complicated.exe
      • TrickerTape.exe
      • Singles.exe
      • Sophos.exe
      • Cogito_Ergo_Sum.exe
      • CERT-Vuln-Info.exe
      • Sk8erBoi.exe
      • IAmWiThYoU.exe
      • Phantom.exe
      • EntradoDePer.exe
      • SiamoDiTe.exe
      • BioData.exe
      • ALavigne.exe
      • <random>.TXT
      • <random>.DOC
    • From. The worm uses the infected computer's default SMTP server and then adds either the senders address or a randomly selected email address to the "From:" line of the email.

  11. The worm will search the %My Documents% directory for filenames with the extension .TXT or .DOC and attach one to the outgoing message.
  12. As part of the email routine, the worm previously created the temporary file %Temporary%\NewBoot.sys, which it (usually) deletes now.
  13. Searches for the file, Icqmapi.dll, by determining the path of the ICQ program files. If the worm finds this file, the worm copies it to the \Windows\System folder and sends itself to all the contacts in the ICQ contact list.
  14. Creates a Script.ini file in the mIRC program files folder. This file will connect to the IRC channel #avrillavigne and send itself to others who join any channels that you join.
  15. Inventories all the network resources searching for open C shares. If the worm finds an open C share, it copies itself to \Recycled\<random string>.exe on the remote system and modifies the Autoexec.bat file of the remote system to load the worm on startup, by adding the following line:
    @win <random string>.exe
  16. Copies itself to \Recycled\<random string>.exe on each local hard drive and modifies the Autoexec.bat file (adding the aforementioned line), so that the worm runs when you start Windows (on Windows 95/98/Me computers only).
  17. Copies itself as a random file name to the KaZaA download folder.
  18. Connects to http:/ / and downloads BackOrifice (detected as BO.Trojan Variant), which is saved to %System%\Bo2k.exe, and creates the registry value:


    under the registry key:

  19. Connects to http:/ / and downloads an unknown executable that is currently unavailable and saves the file to %Temporary%\uploaded.tft
  20. If the day of the month is the 7th, 11th, or 24th, the worm will launch your Web browser to and display a graphic animation on the Windows desktop.


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.


Removal tool
Symantec has provided a tool to remove infections of W32.Lirva.C@mm. Click here to obtain the tool. This is the easiest way to remove this threat and should be tried first.

Manual removal
These instructions are for all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

  1. Restart the computer in Safe mode.
  2. Remove the value that the worm added to the registry, and then restart in Normal mode.
  3. Update the virus definitions.
  4. Run a full system scan and delete all the files detected as W32.Lirva.C@mm.
For specific details on each of these procedures, read the following instructions.

1. Restarting in Safe mode
Restart the computer in Safe mode. All the Windows 32-bit operating systems, except Windows NT, can be restarted in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode ."

2. Removing the value from the registry
Symantec strongly recommends that you back up the registry before you make any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified keys only. For instructions, read the document, "How to make a backup of the Windows registry ."
  1. Click Start, and then click Run. (The Run dialog box appears.)
  2. Type regedit, and then click OK. (The Registry Editor opens.)
  3. Navigate to the key:

  4. In the right pane, delete the value:

    Avril Lavigne - Muse
  5. Exit the Registry Editor.
  6. Restart the computer and allow it to start in normal mode.

3. Updating 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 the 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), in the "Protection" section, at the top of this writeup.
  • Downloading the definitions using the Intelligent Updater. The Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). 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), in the "Protection" section, at the top of this writeup.

    The Intelligent Updater virus definitions are available here. For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, click here.

4. Scanning for and deleting 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.Lirva.C@mm, click Delete.

Writeup By: Eric Chien