W32.Assiral.B@mm

Printer Friendly Page

Discovered: March 02, 2005
Updated: February 13, 2007 12:34:36 PM
Also Known As: Email-Worm.Win32.Ariss.c [Kasp, W32/Laris.worm [McAfee], W32/Assiral-B [Sophos], WORM_ASSIRAL.C [Trend Micro]
Type: Worm
Systems Affected: Windows


W32.Assiral.B@mm is a mass-mailing worm that sends a copy of itself to email addresses gathered from a compromised computer. The worm also ends various processes, some of which may be security related.

The email will have a variable subject and attachment name. The attachment will have a .exe file extension.



Processes deleted by W32.Assiral.B@mm:

    • AGENTSVR.EXE
    • ANTI-TROJAN.EXE
    • ANTIVIRUS.EXE
    • ANTS.EXE
    • APIMONITOR.EXE
    • APLICA32.EXE
    • APVXDWIN.EXE
    • ATCON.EXE
    • ATGUARD.EXE
    • ATRO55EN.EXE
    • ATUPDATER.EXE
    • ATWATCH.EXE
    • AUPDATE.EXE
    • AUTODOWN.EXE
    • AUTOTRACE.EXE
    • AUTOUPDATE.EXE
    • AVCONSOL.EXE
    • AVGSERV9.EXE
    • AVLTMAIN.EXE
    • AVPUPD.EXE
    • AVSYNMGR.EXE
    • AVWUPD32.EXE
    • AVXQUAR.EXE
    • AVprotect9x.exe
    • Au.exe
    • BD_PROFESSIONAL.EXE
    • BIDEF.EXE
    • BIDSERVER.EXE
    • BIPCP.EXE
    • BIPCPEVALSETUP.EXE
    • BISP.EXE
    • BLACKD.EXE
    • BLACKICE.EXE
    • BOOTWARN.EXE
    • BORG2.EXE
    • BS120.EXE
    • CCAPP.exe
    • CDP.EXE
    • CFGWIZ.EXE
    • CFIADMIN.EXE
    • CFIAUDIT.EXE
    • CFINET.EXE
    • CFINET32.EXE
    • CLEAN.EXE
    • CLEANER.EXE
    • CLEANER3.EXE
    • CLEANPC.EXE
    • CMGRDIAN.EXE
    • CMON016.EXE
    • CPD.EXE
    • CPF9X206.EXE
    • CPFNT206.EXE
    • CV.EXE
    • CWNB181.EXE
    • CWNTDWMO.EXE
    • D3dupdate.exe
    • DEFWATCH.EXE
    • DEPUTY.EXE
    • DPF.EXE
    • DPFSETUP.EXE
    • DRWATSON.EXE
    • DRWEBUPW.EXE
    • ENT.EXE
    • ESCANH95.EXE
    • ESCANHNT.EXE
    • ESCANV95.EXE
    • EXANTIVIRUS-CNET.EXE
    • FAST.EXE
    • FIREWALL.EXE
    • FLOWPROTECTOR.EXE
    • FP-WIN_TRIAL.EXE
    • FRW.EXE
    • FSAV.EXE
    • FSAV530STBYB.EXE
    • FSAV530WTBYB.EXE
    • FSAV95.EXE
    • GBMENU.EXE
    • GBPOLL.EXE
    • GUARD.EXE
    • HACKTRACERSETUP.EXE
    • HTLOG.EXE
    • HWPE.EXE
    • IAMAPP.EXE
    • IAMSERV.EXE
    • ICLOAD95.EXE
    • ICLOADNT.EXE
    • ICMON.EXE
    • ICSSUPPNT.EXE
    • ICSUPP95.EXE
    • ICSUPPNT.EXE
    • IFW2000.EXE
    • IPARMOR.EXE
    • IRIS.EXE
    • JAMMER.EXE
    • KAVLITE40ENG.EXE
    • KAVPERS40ENG.EXE
    • KERIO-PF-213-EN-WIN.EXE
    • KERIO-WRL-421-EN-WIN.EXE
    • KERIO-WRP-421-EN-WIN.EXE
    • KILLPROCESSSETUP161.EXE
    • LDPRO.EXE
    • LOCALNET.EXE
    • LOCKDOWN.EXE
    • LOCKDOWN2000.EXE
    • LSETUP.EXE
    • LUALL.EXE
    • LUCOMSERVER.EXE
    • LUINIT.EXE
    • MCAGENT.EXE
    • MCUPDATE.EXE
    • MFW2EN.EXE
    • MFWENG3.02D30.EXE
    • MGUI.EXE
    • MINILOG.EXE
    • MOOLIVE.EXE
    • MRFLUX.EXE
    • MSCONFIG.EXE
    • MSINFO32.EXE
    • MSSMMC32.EXE
    • MU0311AD.EXE
    • NAV80TRY.EXE
    • NAVAPW32.EXE
    • NAVDX.EXE
    • NAVSTUB.EXE
    • NAVW32.EXE
    • NC2000.EXE
    • NCINST4.EXE
    • NDD32.EXE
    • NEOMONITOR.EXE
    • NETARMOR.EXE
    • NETINFO.EXE
    • NETMON.EXE
    • NETSCANPRO.EXE
    • NETSPYHUNTER-1.2.EXE
    • NETSTAT.EXE
    • NISSERV.EXE
    • NISUM.EXE
    • NMAIN.EXE
    • NORTON_INTERNET_SECU_3.0_407.EXE
    • NPF40_TW_98_NT_ME_2K.EXE
    • NPFMESSENGER.EXE
    • NPROTECT.EXE
    • NSCHED32.EXE
    • NTVDM.EXE
    • NUPGRADE.EXE
    • NVARCH16.EXE
    • NWINST4.EXE
    • NWTOOL16.EXE
    • OSTRONET.EXE
    • OUTPOST.EXE
    • OUTPOSTINSTALL.EXE
    • OUTPOSTPROINSTALL.EXE
    • PADMIN.EXE
    • PANIXK.EXE
    • PAVPROXY.EXE
    • PCC2002S902.EXE
    • PCC2K_76_1436.EXE
    • PCCIOMON.EXE
    • PCDSETUP.EXE
    • PCFWALLICON.EXE
    • PCIP10117_0.EXE
    • PDSETUP.EXE
    • PERISCOPE.EXE
    • PERSFW.EXE
    • PF2.EXE
    • PFWADMIN.EXE
    • PLATIN.EXE
    • POPROXY.EXE
    • POPSCAN.EXE
    • PORTDETECTIVE.EXE
    • PPINUPDT.EXE
    • PPTBC.EXE
    • PPVSTOP.EXE
    • PROCEXPLORERV1.0.EXE
    • PROPORT.EXE
    • PROTECTX.EXE
    • PSPF.EXE
    • PURGE.EXE
    • PVIEW95.EXE
    • QCONSOLE.EXE
    • QSERVER.EXE
    • RAV8WIN32ENG.EXE
    • RESCUE.EXE
    • RESCUE32.EXE
    • RRGUARD.EXE
    • RSHELL.EXE
    • RTVSCN95.EXE
    • RULAUNCH.EXE
    • SAFEWEB.EXE
    • SBSERV.EXE
    • SD.EXE
    • SETUPVAMEEVAL.EXE
    • SETUP_FLOWPROTECTOR_US.EXE
    • SFC.EXE
    • SGSSFW32.EXE
    • avserve2.exe
    • SHELLSPYINSTALL.EXE
    • SHN.EXE
    • SMC.EXE
    • SOFI.EXE
    • SPF.EXE
    • SPHINX.EXE
    • SPYXX.EXE
    • SS3EDIT.EXE
    • ST2.EXE
    • SUPFTRL.EXE
    • SUPPORTER5.EXE
    • SYMPROXYSVC.EXE
    • SYSEDIT.EXE
    • TASKMON.EXE
    • TAUMON.EXE
    • TAUSCAN.EXE
    • TC.EXE
    • TCA.EXE
    • TCM.EXE
    • TDS-3.EXE
    • TDS2-98.EXE
    • TDS2-NT.EXE
    • TFAK5.EXE
    • TGBOB.EXE
    • TITANIN.EXE
    • TITANINXP.EXE
    • TRACERT.EXE
    • TRJSCAN.EXE
    • TRJSETUP.EXE
    • TROJANTRAP3.EXE
    • UNDOBOOT.EXE
    • UPDATE.EXE
    • VBCMSERV.EXE
    • VBCONS.EXE
    • VBUST.EXE
    • VBWIN9X.EXE
    • VBWINNTW.EXE
    • VCSETUP.EXE
    • VFSETUP.EXE
    • VIRUSMDPERSONALFIREWALL.EXE
    • VNLAN300.EXE
    • VNPC3000.EXE
    • VPC42.EXE
    • VPFW30S.EXE
    • VPTRAY.EXE
    • VSCENU6.02D30.EXE
    • VSECOMR.EXE
    • VSHWIN32.EXE
    • VSISETUP.EXE
    • VSMAIN.EXE
    • VSMON.EXE
    • VSSTAT.EXE
    • VSWIN9XE.EXE
    • VSWINNTSE.EXE
    • VSWINPERSE.EXE
    • W32DSM89.EXE
    • W9X.EXE
    • WATCHDOG.EXE
    • WEBSCANX.EXE
    • WGFE95.EXE
    • WINRECON.EXE
    • WNT.EXE
    • WRCTRL.EXE
    • WSBGATE.EXE
    • WYVERNWORKSFIREWALL.EXE
    • XPF202EN.EXE
    • ZAPRO.EXE
    • ZAPSETUP3001.EXE
    • ZATUTOR.EXE
    • ZAUINST.EXE
    • ZONALM2601.EXE
    • ZONEALARM.EXE
    • lexplore.exe
    • Drunk_lol.pif
    • Webcam_004.pif
    • sexy_bedroom.pif
    • naked_party.pif
    • love_me.pif
    • osm.exe
    • cz.exe
    • Webcam.pif
    • hahahaha.pif
    • me_2005.pif
    • sister.pif
    • winhost.exe
    • LOL.scr
    • Webcam.pif
    • naked_drunk.pif
    • LMAO.pif
    • ROFL.pif
    • underware.pif
    • Hot.pif
    • new_webcam.pif
    • msnus.exe
    • sexy.jpg
    • updates.exe
    • msnmsr.exe
    • bedroom-things.pif
    • naked_drunk.pif
    • my_pussy.pif
    • ROFL.pif
    • Hot.pif
    • ISASS.EXE
    • Beautiful Ass.pif
    • John Kerry as Super Chicken.scr
    • Kool.pif
    • Me & you pic!.pif
    • Me Pissed!.pif
    • sexy.pif
    • She Could Fit her Ass in a Teacup.pif
    • she's fuckin fit.pif
    • titanic2.jpg.pif
    • winis.exe
    • nvsc32.exe


Antivirus Protection Dates

  • Initial Rapid Release version March 03, 2005
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version March 03, 2005
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date March 06, 2005

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

Writeup By: Yana Liu

Discovered: March 02, 2005
Updated: February 13, 2007 12:34:36 PM
Also Known As: Email-Worm.Win32.Ariss.c [Kasp, W32/Laris.worm [McAfee], W32/Assiral-B [Sophos], WORM_ASSIRAL.C [Trend Micro]
Type: Worm
Systems Affected: Windows


When W32.Assiral.B@mm is executed, it performs the following actions:

  1. Copies itself as the following:

    • %Windir%\SP00Lsv32.pif
    • %System%\MSLARISSA.pif
    • %System%\CmdPrompt32.pif

      Notes:
    • %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. Adds the values:

    "MSLARISSA" = "%System%\MSLARISSA.pif"
    "Command Prompt32" = "%System%\CmdPrompt32.pif"
    "(L4r1$$4) (4nt1) (V1ruz)" = "%Windir%\SP00Lsv32.pif"

    to the registry key:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

    so that it is executed every time Windows starts.

  3. Creates the mutex "-)(-=|L4r1$$4|=-)(-" so that only one instance of the worm runs in memory.

  4. Creates and executes C:\WINDOWS\WinVBS.vbs.

  5. Adds the values:

    "NoRun" = "1"
    "NoDrives" = "67108863"

    to the registry subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
    Policies\Explorer

    to disable various functions in Windows.

  6. Adds the values:

    "DisableRegistryTools" = "1"
    "NoAdminPage" = "1"

    to the registry subkey:

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

    to disable various functions in Windows.

  7. Adds the value:

    "Disabled" = "1"

    to the registry subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
    Policies\WinOldApp

    to disable various functions in Windows.

  8. Opens a hidden browser window and downloads a file containing Trojan.Klassir from the geocities.com domain.

  9. Searches for email addresses in files with an .ht* extension in the %Windir% folder and the current folder. The Trojan also gathers email addresses from .ht* files in the folder found by querying the following registry entry:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
    Explorer\Shell Folders

  10. Attempts to copy itself as LOVE_LETTER_FOR_YOU.pif to all fixed, remote, and removable drives.

  11. Attempts to end processes, some of which may be security-related. A full list of the processes deleted is given in the Additional Information section below.

  12. Attempts to delete all .DLL and .EXE files from the following folders:

    • C:\WINDOWS\System32
    • C:\WINDOWS\System
    • C:\WINDOWS

  13. Creates the following .txt files:

    • C:\MESSAGE_TO_USER.txt
    • C:\MESSAGE_TO_AVs.txt
    • C:\MESSAGE_TO_BROPIA.txt

  14. Uses its own SMTP engine to send email messages to email addresses found. The email may have the following characteristics:

    From: MSLarissa@Admin.com

    Subject:
    One of the following:

    • Re: Message
    • Re: Letter
    • Re: Information
    • I LOVE YOU
    • Re: Your Documents
    • Re: Account Info
    • Windows Update
    • Re: My Letter
    • Re: Docs
    • Re: Your Email Info

    Message body:
    One of the following:

    • The message is located in the attachments.
    • The letter you requested is in the attachments.
    • Information attached.
    • Kindly read and reply to my LOVE LETTER in the attachments :-)
    • The documents you requested are in the attachments.
    • Info reguarding your Email account is in the attachments.
    • Dear Windows User,
    • Please download the windows update included in the attachments.
    • My letter is in the attachments.
    • Please read the documents included in the attachments
    • Your email account is about to expire, please check the attachments for details.

    Attachment:
    One of the following:

    • Letter.exe
    • Information.exe
    • LOVE_LETTER_FOR_YOU.exe
    • Documents.exe
    • Attached_Message.exe
    • Microsoft_Update.exe
    • Private_Letter.exe
    • Private_Document.exe
    • Important_Message.exe


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: Yana Liu

Discovered: March 02, 2005
Updated: February 13, 2007 12:34:36 PM
Also Known As: Email-Worm.Win32.Ariss.c [Kasp, W32/Laris.worm [McAfee], W32/Assiral-B [Sophos], WORM_ASSIRAL.C [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. Do one of the following:
    • Windows 95/98/Me: Restart the computer in Safe mode.
    • Windows NT/2000/XP: End the malicious process.
  4. Run a full system scan and delete all the files detected as W32.Assiral.B@mm.
  5. Restore the Registry Editor.
  6. Reverse the changes made to the registry.
  7. Reset the Internet Explorer settings.
For 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, 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 restart the computer in Safe mode or end the malicious process
    Windows 95/98/Me
    Shut down the computer and turn off the power. Wait for at least 30 seconds, and then restart the computer in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode."

    Windows NT/2000/XP
    To end the malicious process:
    1. Press Ctrl+Alt+Delete once.
    2. Click Task Manager.
    3. Click the Processes tab.
    4. Double-click the Image Name column header to alphabetically sort the processes.
    5. Scroll through the list and look for W32.Assiral.B@mm.
    6. If you find the file, click it, and then click End Process.
    7. Exit the Task Manager.
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 as infected with W32.Assiral.B@mm, click Delete.
  4. If you are still in Safe mode, restart the computer in Normal mode before proceeding to the next section.
5. To restore the Registry Editor
  1. Click Start > Programs > Accessories > Notepad.
  2. Type:

    REGEDIT4

    [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System]
    DisableRegistryTools = dword:00000000

    [HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System]
    DisableRegistryTools = dword:00000000

  3. Save the file as fix.reg in My Documents.

  4. Click Start > Programs > Accessories > Command Prompt.

  5. Type cd %Userprofile%\My Documents.

    Note: %Userprofile% is a variable that refers to the current user's profile folder. By default, this is C:\Documents and Settings\<Current User> (Windows NT/2000/XP).

  6. Type regedit /s fix.reg to unlock the Registry Editor.

  7. Type regedit to open the Registry Editor.

6. To reverse the changes made to 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 subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

  4. In the right pane, delete the values:

    "MSLARISSA" = "%System%\MSLARISSA.pif"
    "Command Prompt32" = "%System%\CmdPrompt32.pif"
    "(L4r1$$4) (4nt1) (V1ruz)" = "%Windir%\SP00Lsv32.pif"

  5. Navigate to the subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
    Policies\Explorer

  6. In the right pane, delete the value:

    "NoRun" = "1"

  7. Navigate to the subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
    Policies\WinOldApp

  8. In the right pane, delete the value:

    "Disabled" = "1"

  9. Navigate to the subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
    Policies\Explorer

  10. In the right pane, delete the value:

    "NoDrives" = "67108863"

  11. Navigate to the subkey:

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

  12. In the right pane, delete the value:

    "NoAdminPage" = "1"

  13. Exit the Registry Editor.

  14. Restart the computer in Normal mode. For instructions, read the section on returning to Normal mode in the document, "How to start the computer in Safe Mode."


7. To restore default settings in Internet Explorer
  1. Click Start > Settings > Control Panel
  2. Select Internet Options
  3. Select the Programs tab
  4. Click Reset Web Settings
  5. Click OK
  6. Exit Control Panel


Writeup By: Yana Liu