W32.Sowsat.J@mm

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Discovered: August 22, 2003
Updated: February 13, 2007 12:05:48 PM
Type: Worm
Systems Affected: Windows



W32.Sowsat.J@mm is a variant of W32.Sowsat@mm , a mass-mailing worm that spreads by using its own SMTP engine and spreads through IRC. The email has a variable subject line and attachment name. The attachment should have a .exe file extension.

The worm is written in Borland Delphi and is packed with UPX.

Antivirus Protection Dates

  • Initial Rapid Release version August 25, 2003
  • Latest Rapid Release version August 08, 2016 revision 023
  • Initial Daily Certified version August 25, 2003
  • Latest Daily Certified version August 09, 2016 revision 001
  • Initial Weekly Certified release date August 27, 2003

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

Writeup By: Scott Gettis

Discovered: August 22, 2003
Updated: February 13, 2007 12:05:48 PM
Type: Worm
Systems Affected: Windows


When W32.Sowsat.J@mm runs, it performs the following actions:

  1. Creates the folder, C:\Windows\Temp, if it does not exist.

  2. Copies itself into C:\Windows\Temp with the name Taskmgr32N.exe (where N is a number greater than or equal to zero).

  3. Creates a zip file in C:\Windows\Temp with the name M.zip, where M is the number of times the worm has run on the computer.

  4. Creates a folder in C:\Windows\Temp with a 12-digit name, which is a representation of the time at which the worm runs (for example, 070803112255 stands for 11:22:55 on 07 August 2003).

  5. Adds the values:

    "cftmon32" = "Java Compiler"
    "jto" = "<the name of the folder created in step 4>"
    "pcount" = "<the number of times the worm has run>"

    to the registry key:

    HKEY_CURRENT_USER\Software\Microsoft\Windows

  6. Adds the value:

    "cftmon32"="c:\windows\temp\taskmgrN.exe" (where N has the same value as in step 2).

    to the registry key:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

    so that the worm runs when you start Windows.

  7. Searches for the HTML files containing email addresses and sends itself to those addresses.

  8. Attempts to send the zip file created in step 3 to its creator via SMTP.

  9. Connects to the SMTP server, smtp.uol.com.br, and sends one of the following four email messages:

    Message 1:
    From:
    support@symantec.com
    Subject:
    Symantec-Virus-Warning
    Message:
    New virus in "The Wild" called "W32/Cow".Spreads through e-mail and IRC.A solution is this free program.Send this message to your friends.
    Thank you, Symantec
    Attachment:
    varies

    Message 2:
    From:
    piadeiros@risadinha.com.br
    Subject:
    Piada do Paciente Galo
    Message:
    Um paciente chegou com o psiquiatra e disse: - Doutor, eu sou um galo...
    Attachment:
    varies

    Message 3:
    From:
    jonas.rc@yahoo.com.br
    Subject:
    Ei, psiu...
    Message:
    Nada. Te peguei...Gosto muito de voc, viu ? Estou com saudades. De seu amigo, Jonas.
    Attachment:
    varies

    Message 4:
    From:
    notice@programese.kit.net
    Subject:
    Bom dia !!!
    Message:
    Feliz Aniversrio !!!
    Attachment:
    varies

In August 2003, Symantec Security Response received reports that an individual was sending email, which claims to be sent from Symantec, to get the recipient to download and execute this Worm.

The email has the following characteristics:

From: symantec-bb [symantec-bb@uol.com.br]
Subject: Alerta de Segurança da Symantec

The email may appear as the following:


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: Scott Gettis

Discovered: August 22, 2003
Updated: February 13, 2007 12:05:48 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. Update the virus definitions.
  3. Run a full system scan and delete all the files detected as W32.Sowsat.J@mm or W32.Sowsat@mm.
  4. Delete the value added to the registry.
For specific details on each of these steps, read the following instructions.

1. Disabling 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:
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. 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 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 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).

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

3. 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.Sowsat.J@mm or W32.Sowsat@mm, click Delete.

4. Deleting the value from the registry

CAUTION : 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 keys only. Read the document, "How to make a backup of the Windows registry ," for instructions.
  1. Click Start, and then click Run. (The Run dialog box appears.)
  2. Type regedit

    Then click OK. (The Registry Editor opens.)

  3. Navigate to the key:

    HKEY_CURRENT_USER\Software\Microsoft\Windows

  4. In the right pane, delete the values:

    cftmon32
    jto
    pcount

  5. Navigate to the key:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

  6. In the right pane, delete the value:

    ctfmon32

  7. Exit the Registry Editor.


Writeup By: Scott Gettis