W32.Sowsat.J@mm

SUMMARY

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.

Protection

• Virus Definitions (LiveUpdate™ Weekly) August 27, 2003
• Virus Definitions (Intelligent Updater) August 25, 2003

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Moderate

Damage

• Damage Level: Low
• Payload: Sends itself to all the email addresses found, by searching HTML files.

Distribution

• Distribution Level: High
• Subject of Email: Varies
• Name of Attachment: Varies with .exe file extension

TECHNICAL DETAILS

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

1. Creates the folder, C:WindowsTemp, if it does not exist.
   
   
2. Copies itself into C:WindowsTemp with the name Taskmgr32N.exe (where N is a number greater than or equal to zero).
   
   
3. Creates a zip file in C:WindowsTemp 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:WindowsTemp 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_USERSoftwareMicrosoftWindows
   
   
6. Adds the value:
   
   "cftmon32"="c:windows emp askmgrN.exe" (where N has the same value as in step 2).
   
   to the registry key:
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun
   
   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":

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended 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 (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• 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.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. 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.

REMOVAL

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:

• "How to disable or enable Windows Me System Restore"
• "How to turn off or turn on Windows XP System Restore"

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.
   • For Norton AntiVirus consumer products: Read the document, "How to configure Norton AntiVirus to scan all files."
   • For Symantec AntiVirus Enterprise products: Read the document, "How to verify that a Symantec Corporate antivirus product is set to scan all 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_USERSoftwareMicrosoftWindows
   
   
4. In the right pane, delete the values:
   
   cftmon32
   jto
   pcount
   
   
5. Navigate to the key:
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun
   
   
6. In the right pane, delete the value:
   
   ctfmon32
   
   
7. Exit the Registry Editor.