W32.Sowsat@mm

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Discovered: April 30, 2002
Updated: February 13, 2007 11:59:26 AM
Also Known As: W32/Sowsat@MM
Type: Worm
Systems Affected: Windows


W32.Sowsat@mm is a mass-mailing worm that spreads by using its own SMTP engine; it also spreads through IRC. The worm will arrive in a message with the attachment Setupc.exe.

Antivirus Protection Dates

  • Initial Rapid Release version April 30, 2002
  • Latest Rapid Release version August 08, 2016 revision 023
  • Initial Daily Certified version April 30, 2002
  • Latest Daily Certified version August 09, 2016 revision 001
  • Initial Weekly Certified release date May 01, 2002

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

Writeup By: Douglas Knowles

Discovered: April 30, 2002
Updated: February 13, 2007 11:59:26 AM
Also Known As: W32/Sowsat@MM
Type: Worm
Systems Affected: Windows


When W32.Sowsat@mm is executed, it does the following:

It copies itself to:

  • %System%\Sysc#.exe (where # could be any number from 0 to 9)
  • %System%\Setupc.exe

NOTE: %System% is a variable. The worm locates the \Windows\System folder (by default this is C:\Windows\System or C:\Winnt\System32) and copies itself to that location.

If Winzip is installed on the computer, it compresses the file

%System%\Sysc#.exe

into

%System%\Osc#.zip

W32.Sowsat@mm then sends itself to all email addresses that it finds in .htm files that are in the Temp or Temporary Internet Files folders.

It connects to the SMTP server "mail.terrasat.ro" and sends one of the following four email messages:

Message 1

From: AVP-Team(AVP.Mailer@avp.com)
Subject: AVP-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, AVP Team
Attachment: Setupc.exe

Message 2

From: Crazy Games inc. -New gaming company(Crazygames@crazygamez.com)
Subject:  freeware nice game
Message: hya, chaeck this cool freeware!
Attachment: Setupc.exe

Message 3

From: Your friend(john@yahoo.com)\
Subject: My cool, litle program
Message: Something I programmed.It's really cool!
Attachment: Setupc.exe

Message 4

From: Screensaver-Demo coder(Demos@screensave.org)
Subject: Kewl FX screensaver
Message: A nice FX-screensaver.Better than the last one!
Attachment: Setupc.exe

The worm adds the value

Cow       Mooo

to the registry key

HKEY_CURRENT_USER\Software\Microsoft\Windows

It also adds the value

CoW       %System%\Sysc#.exe

to the registry key

KEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

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: Douglas Knowles

Discovered: April 30, 2002
Updated: February 13, 2007 11:59:26 AM
Also Known As: W32/Sowsat@MM
Type: Worm
Systems Affected: Windows


Delete files that are detected as W32.Sowsat@mm, and remove the values that the worm added to the registry.

To delete the W32.Sowsat@mm files:

  1. Obtain the most recent virus definitions. There are two ways to do this:
    • Run LiveUpdate. LiveUpdate is the easiest way to obtain virus definitions. These virus definitions have undergone full quality assurance testing by Symantec Security Response and are posted to the LiveUpdate servers one time each week (usually Wednesdays) unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, look at the Virus Definitions (LiveUpdate) line at the top of this write-up.
    • Download the definitions using the Intelligent Updater. Intelligent Updater virus definitions have undergone full quality assurance testing by Symantec Security Response. They are posted on U.S. business days (Monday through Friday). They must be downloaded from the Symantec Security Response Web site and installed manually. To determine whether definitions for this threat are available by the Intelligent Updater, look at the Virus Definitions (Intelligent Updater) line at the top of this write-up.

      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.
  2. Start Norton AntiVirus (NAV), and make sure that NAV is configured to scan all files. For instructions on how to do this, read the document How to configure Norton AntiVirus to scan all files.
  3. Run a full system scan.
  4. Delete all files that are detected as W32.Sowsat@mm.

To remove the value from the registry:

CAUTION : 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 only the keys that are specified. Read the document How to make a backup of the Windows registry for instructions.
  1. Click Start, and click Run. The Run dialog box appears.
  2. Type regedit and then click OK. The Registry Editor opens.
  3. Navigate to the following key:

    HKEY_CURRENT_USER\Software\Microsoft\Windows
  4. In the right pane, delete the following value:

    Cow       Mooo
  5. Navigate to the following key:

    KEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
  6. In the right pane, delete the following value:

    CoW       %System%\Sysc#.exe
  7. Click Registry, and click Exit.


Writeup By: Douglas Knowles