W32.Chet@mm

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Discovered: September 10, 2002
Updated: February 13, 2007 11:40:26 AM
Also Known As: W32/Chet@MM [McAfee], W32/Chet-A [Sophos], Win32.Chet [CA], WORM_CHET.A [Trend], I-Worm.Chet [AVP]
Type: Worm
Systems Affected: Windows


W32.Chet@mm is a mass-mailing worm that attempts to send itself to all email addresses in Windows Address Book. The email has the following characteristics,

From:  main@world.com
Subject:  All people!!
Attachment: 11september.exe

NOTE: The attachment name contains a space at the end of the file name.

Antivirus Protection Dates

  • Initial Rapid Release version September 11, 2002
  • Latest Rapid Release version November 04, 2016 revision 023
  • Initial Daily Certified version September 11, 2002
  • Latest Daily Certified version November 05, 2016 revision 001
  • Initial Weekly Certified release date September 11, 2002

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

Writeup By: Yana Liu

Discovered: September 10, 2002
Updated: February 13, 2007 11:40:26 AM
Also Known As: W32/Chet@MM [McAfee], W32/Chet-A [Sophos], Win32.Chet [CA], WORM_CHET.A [Trend], I-Worm.Chet [AVP]
Type: Worm
Systems Affected: Windows


When W32.Chet@mm runs, it does the following:

It copies itself as C:\%system%\Synchost1.exe,

NOTE: %system% is a variable. The worm locates the System folder and copies itself to that location. By default this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).

It adds the value

ICQ1 C:\%system%\synchost1.exe

to the registry key

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

This causes the worm to run when you restart Windows.

The worm creates a file named C:\Boot.txt. This file is zero bytes in length.

The worm searches the registry to find the location of the Windows Address Book file. It attempts to email itself to all contacts in the Windows Address Book. However, Security Response has been unable to reproduce this behavior. If it were successful, the email would have the following characteristics:

From:  main@world.com
Subject:  All people!!
Attachment: 11september.exe
Message:
Dear ladies and gentlemen!
The given letter does not contain viruses, and is not Spam.
We ask you to be in  earnest to this letter. As you know America and
England have begun bombardment of  Iraq, cause of its threat for all the world.
It isn't the truth. The real reason is  in money laundering and also to cover up traces
after acts of terrorism  September, 11, 2001. Are real proofs of connection between
Bush and Al-Qaeda  necessary for you? Please! There is a friendly dialogue between
Bin Laden and the secretary of a state security of USA in the given photos.
In the following photo you'll see, how FBI discusses how to strike over New York to lose
people as much as possible. And the document representing the super confidential
agreement between CIA and Al-Qaeda is submitted to your attention. All this
circus was specially played to powder brains!! You'll find out the truth.
Naked truth, instead of TV showed.
For your convenience, and to make letter less, all documentary  materials
(photos and MS Word documents) are located in one EXE file.  Open it, and all materials will be
installed on your computer. You will receive the  freshest and classified
documents automatically from our site.
It isn't a virus! You can trust us absolutely. We hope, that it will open your
eyes on many things occurring in this world.

The worm also attempts to send email to some email addresses predefined in the worm code. The email has the following characteristics,
From:  Fu****
To:  Ripper
Subject:
Otchet from usersfirst
or
Otchet

The body of the email message contains a list of contacts in the Windows Address Book, IP addresses, and the name of the infected computer.

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: September 10, 2002
Updated: February 13, 2007 11:40:26 AM
Also Known As: W32/Chet@MM [McAfee], W32/Chet-A [Sophos], Win32.Chet [CA], WORM_CHET.A [Trend], I-Worm.Chet [AVP]
Type: Worm
Systems Affected: Windows


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

  1. Update the virus definitions.
  2. Run a full system scan, and delete all files that are detected as W32.Chet@mm.
  3. Delete the value

    ICQ1 C:\%System%\synchost1.exe

    from the registry key

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
For details on how to do this, read the following instructions.

To update the virus definitions:
All virus definitions receive full quality assurance testing by Symantec Security Response before being posted to our servers. There are two ways to obtain the most recent virus definitions:
  • Run LiveUpdate, which is the easiest way to obtain virus definitions. These virus definitions 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 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.

To scan for and delete the infected files:
  1. Start your Symantec antivirus program, and make sure that it is configured to scan all files.
  2. Run a full system scan.
  3. If any files are detected as infected with W32.Chet@mm, click Delete.

To remove the value that the worm added to 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 key

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
  4. In the right pane, delete the value

    ICQ1 C:\%System%\synchost1.exe
  5. Exit the Registry Editor.


Writeup By: Yana Liu