Information on Page/ Symantec Security Response - W32.Klez.H@mm

[Guest guest]

Good morning. This is from Norton. I get my update every day and scan

twice a day, automatically.

Barb in Arlington

http://www.symantec.com/avcenter/venc/data/w32.klez.h (AT) mm (DOT) html

--

" When we do the best that we can, we never know what miracle is wrought

in our life,

or in the life of another. " --Helen Keller

© 1995-2002 Symantec Corporation.

All rights reserved.

Legal Notices

Privacy Policy

W32.Klez.H@mm

Discovered on: April 17, 2002Last Updated on: May 10, 2002 at 11:27:01 AM PDT

W32.Klez.H@mm is a modified variant of the worm W32.Klez.E (AT) mm (DOT) This variant is capable of spreading by email and network shares. It is also capable of infecting files.

Removal tool

Symantec has provided a tool to remove infections of all known variants of W32.Klez and W32.ElKern. Click here to obtain the tool.

This is the easiest way to remove these threats and should be tried first.

Note on W32.Klez.gen@mm detections:

W32.Klez.gen@mm is a generic detection that detects variants of W32.Klez. Computers that are infected with W32.Klez.gen@mm have most likely been exposed to either W32.Klez.E@mm or W32.Klez.H (AT) mm (DOT) If your computer is detected as infected with W32.Klez.gen@mm, download and run the tool. In most cases, the tool will be able to remove the infection.

Also Known As: W32/Klez.h@MM, WORM_KLEZ.H, W32/Klez-G, I-Worm.Klez.h, Klez.H, W32/Klez.H, Win32.Klez.H, WORM_KLEZ.I

Type: Worm

Beta Virus Definitions

April 17, 2002

Virus Definitions (Intelligent Updater)*

April 17, 2002

Virus Definitions (LiveUpdate)**

April 17, 2002

*

Intelligent Updater virus definitions are released daily, but require manual download and installation.Click here to download manually.

**

LiveUpdate virus definitions are usually released every Wednesday.Click here for instructions on using LiveUpdate.

Wild:

Number of infections: More than 1000

Number of sites: More than 10

Geographical distribution: High

Threat containment: Moderate

Removal: Difficult

Threat Metrics

Wild:High

Damage:Medium

Distribution:High

Damage:

Payload: This worm infects executables by creating a hidden copy of the original host file and then overwriting the original file with itself. The hidden copy is encrypted, but contains no viral data. The name of the hidden file is the same as the original file, but with a random extension.

Large scale e-mailing: This worm searches the Windows address book, the ICQ database, and local files for email addresses. The worm sends an email message to these addresses with itself as an attachment.

Releases confidential info: Worm randomly chooses a file from the machine to send along with the worm to recipients. So files with the extensions:

".mp8" or ".txt" or ".htm" or ".html" or ".wab" or ".asp" or ".doc" or ".rtf" or ".xls" or ".jpg" or ".cpp" or ".pas" or ".mpg" or ".mpeg" or ".bak" or ".mp3" or ".pdf" would be attached to e-mail messages along with the viral attachment.

Distribution:

Subject of email: Random

Name of attachment: Random

When this worm is executed, it does the following:

It copies itself to \%System%\Wink<random characters>.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.

It adds the value

Wink<random characters> %System%\Wink<random characters>.exe

to the registry key

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

or it creates the registry key

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Wink[random characters]

and inserts a value in that subkey so that the worm is executed when you start Windows.

The worm attempts to disable on-access virus scanners and some previously distributed worms (such as W32.Nimda and CodeRed) by stopping any active processes. The worm removes the startup registry keys used by antivirus products and deletes checksum database files including:Anti-Vir.datChklist.datChklist.msChklist.cpsChklist.tavIvb.ntzSmartchk.msSmartchk.cpsAvgqt.datAguard.dat

Local and Network Drive copying:

The worm copies itself to local, mapped, and network drives as: A random file name that has a double extension. For example, Filename.txt.exe. A .rar archive that has a double extension. For example, Filename.txt.rar.

Email:

This worm searches the Windows address book, the ICQ database, and local files for email addresses. The worm sends an email message to these addresses with itself as an attachment. The worm contains its own SMTP engine and attempts to guess at available SMTP servers. For example, if the worm encounters the address user@... it will attempt to send email via the server smtp.abc123.com.

The subject line, message bodies, and attachment file names are random. The From address is randomly-chosen from email addresses that the worm finds on the infected computer.

The worm will search files that have the following extensions for email addresses:mp8.exe.scr.pif.bat.txt.htm.html.wab.asp.doc.rtf.xls.jpg.cpp.pas.mpg.mpeg.bak.mp3.pdf

In addition to the worm attachment, the worm also may attach a random file from the computer. The file will have one of the following extensions:mp8.txt.htm.html.wab.asp.doc.rtf.xls.jpg.cpp.pas.mpg.mpeg.bak.mp3.pdf

As a result, the email message would have 2 attachments, the first being the worm and the second being the randomly-selected file.

The email message that this worms sends is composed of " random " strings. The subject can be one of the following:

Undeliverable mail-- " [Random word] " Returned mail-- " [Random word] " a [Random word] [Random word] gamea [Random word] [Random word] toola [Random word] [Random word] websitea [Random word] [Random word] patch[Random word] removal toolshow are youlet's be friendsdarlingso cool a flash,enjoy ityour passwordhoneysome questionsplease try againwelcome to my hometownthe Garden of Edenintroduction on ADSLmeeting noticequestionnairecongratulationssos!japanese girl VS playboylook,my beautiful girl friendeager to see youspice girls' vocal concertjapanese lass' sexy pictures

The random word will be one of the following:newfunnynicehumourexcitegoodpowfulWinXPIE 6.0W32.ElkernW32.Klez.ESymantecMcafeeF-SecureSophosTrendmicroKaspersky

The body of the email message is random.

NOTES:Because this worm uses a randomly chosen address that it finds on an infected computer as the " From: " address, numerous cases have been reported in which users of uninfected computers received complaints that they sent an infected message to someone else.

For example, is using a computer that is infected with W32.Klez.H (AT) mm (DOT) is not using a antivirus program or does not have current virus definitions. When W32.Klez.H@mm performs its emailing routine, it finds the email address of Harold Logan. It inserts Harold's email address into the " From: " portion of an infected message that it then sends to Janet Bishop. Janet then contacts Harold and complains that he sent her an infected message, but when Harold scans his computer, Norton AntiVirus does not find anything--as would be expected--because his computer is not infected.

If you are using a current version of Norton AntiVirus and have the most recent virus definitions, and a full system scan with Norton AntiVirus set to scan all files does not find anything, you can be confident that your computer is not infected with this worm.

There have been several reports that, in some cases, if you receive a message that the virus has sent using its own SMTP engine, the message appears to be a " postmaster bounce message " from your own domain. For example, if your email address is jsmith@..., you could receive a message that appears to be from postmaster@..., indicating that you attempted to send email and the attempt failed. If this is the false message that is sent by the virus, the attachment includes the virus itself. Of course, such attachments should not be opened.

If the message is opened in an unpatched version of Microsoft Outlook or Outlook Express, the attachment may be automatically executed. Information about this vulnerability and a patch are available at

http://www.microsoft.com/technet/security/bulletin/MS01-020.asp

Virus Insertion:

This worm inserts the virus W32.Elkern.4926 as a file with a random name in the \%Program Files% folder and executes it.

NOTE: %Program Files% is a variable. The worm locates the \Program Files folder (by default this is C:\Program Files and copies the virus to that location.

Symantec Security Response offers these suggestions on how to configure Symantec products in order to minimize your exposure to this threat.

Norton AntiVirus for Gateways (SMTP)

Block incoming attachments with .bat, .exe, .pif and .scr extensions

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, a telnet server, 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.

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 using the removal tool

Removal tool

Symantec has provided a tool to remove infections of all known variants of W32.Klez and W32.ElKern. Click here to obtain the tool.

This is the easiest way to remove these threats and should be tried first.

Note on W32.Klez.gen@mm detections:

W32.Klez.gen@mm is a generic detection that detects variants of W32.Klez. Computers that are infected with W32.Klez.gen@mm have most likely been exposed to either W32.Klez.E@mm or W32.Klez.H (AT) mm (DOT) If your computer is detected as infected with W32.Klez.gen@mm, download and run the tool. In most case, the tool will be able to remove the infection..

Manual removal procedure for Windows 95/98/Me

If W32.Klez.H@mm has activated, in most cases you will not be able to start Norton AntiVirus. Once this worm has executed, it can be difficult and time consuming to remove. The procedure that you must use to do this varies with the operating system. Please read and follow all instructions for your operating system.

Follow the instructions in the order shown. Do not skip any steps. This procedure has been tested and will work in most cases.

NOTE: Due to the damage that can be done by this worm, and depending on how many times the worm has executed, the process may not work in all cases. If it does not, you may need to obtain the services of a computer consultant.

1. Download virus definitionsDownload the definitions using the Intelligent Updater. Save the file to the Windows desktop. This is a necessary first step to make sure that you have current definitions available later in the removal process. Intelligent Updater virus definitions are available at

http://securityresponse.symantec.com/avcenter/defs.download.html

For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, read the document How to update virus definition files using the Intelligent Updater.

2. Restart the computer in Safe modea. Shut down the computer and turn off the power. Wait thirty seconds. Do not skip this step.

b. Restart the computer in Safe mode. For instructions, read the document How to restart Windows 9x or Windows Me in Safe mode.

3. Edit the registryYou must edit the key HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Current Version\Run and remove the wink???.exe value after you write down the exact name of the wink file.

CAUTION: We strongly recommend that you back up the system registry before you make any changes. Incorrect changes to the registry could result in permanent data loss or corrupted files. Please make sure that you modify only the keys that are specified. Please see the document How to back up the Windows registry before you proceed.a. Click Start, and click Run. The Run dialog box appears.

b. Type regedit and then click OK. The Registry Editor opens.

c. Navigate to the following key:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

d. In the right pane, look for the following values:

Wink[random characters] %System%\Wink[random characters].exe

WQK %System%\Wqk.exe

e. Write down the exact file name of the Wink[random characters].exe file

f. Delete the Wink[random characters] value and the WQK value (if it exists).

g. Navigate to and expand the following key:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services

h. In the left pane, under the \Services key, look for the following subkey, and delete it, if it exists:

\Wink[random characters]

NOTE: This probably will not exist on Windows 95/98/Me-based computers, but you should check for it anyway.

i. Click Registry, and click Exit.

4. Delete the actual Wink[random characters] fileUsing Windows Explorer, open the C:\Windows\System folder and locate the Wink[random characters].exe file. (Depending on your system settings, the .exe extension may not be displayed.)

NOTE: If you have Windows installed to a location other than C:\Windows, make the appropriate substitution.

5. Empty the Recycle BinRight-click the Recycle Bin on the Windows desktop, and click Empty Recycle Bin.

6. Run the Intelligent UpdaterDouble-click the file that you downloaded in Step 1. Click Yes or OK if prompted.

7. Restart the computerShut down the computer, and turn off the power. Wait 30 seconds, and then restart it.

CAUTION: This step is very important. Reinfection will occur if this is not followed.

Allow the computer to start normally. If any files are detected as infected by W32.Klez.H@mm or W32.Klez.gen@mm, Quarantine them. Some of the files that you may find are Luall.exe, Rescue32.exe, and Nmain.exe.

8. Scan with Norton AntiVirus (NAV) from a command lineBecause some NAV files were damaged by the worm, you must scan from a command line.

NOTE: These instructions are only for consumer versions of NAV. The file Navw32.exe is not part of Enterprise versions of NAV such as NAVCE. The NAVCE command line scanner, Vpscan.exe, will not remove the worm.

a. Click Start, and click Run.

b. Type--or copy and paste--the following, and then click OK:

NAVW32.EXE /L /VISIBLE

c. Allow the scan to run. Quarantine any additional files that are detected.

9. Restart the computerAllow the computer to start normally.

10. Reinstall NAV

NOTE: If you are using NAV 2002 on Windows XP, this may not be possible on all systems. You can, however, try the following: Open the Control Panel, double-click Administrative Tools, and then double-click Services. In the list, select Windows Installer. Click Action and then click Start.

Follow the instructions in the document How to restore Norton AntiVirus after removing a virus to reinstall NAV.

11. Restart the computer and scan againa. Shut down the computer, and turn off the power. Wait 30 seconds and then restart it.

CAUTION: This step is very important. Reinfection will occur if this is not followed.

b. Run LiveUpdate and download the most current virus definitions.

c. 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.

d. Run a full system scan. Quarantine any files that are detected as infected by W32.Klez.H@mm or W32.Klez.gen (AT) mm (DOT)

Manual removal procedure for Windows 2000/XP

1. Download virus definitionsDownload the definitions using the Intelligent Updater. Save the file to the Windows desktop. This is a necessary first step to make sure that you have current definitions available later in the removal process. Intelligent Updater virus definitions are available at

http://securityresponse.symantec.com/avcenter/defs.download.html

For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, read the document How to update virus definition files using the Intelligent Updater.

2. Restart the computer in Safe modea. Shut down the computer and turn off the power. Wait thirty seconds. Do not skip this step.

b. You must do this as the first step. All Windows 32-bit operating systems except Windows NT can be restarted in Safe mode. Read the document for your operating system.How to start Windows XP in Safe modeHow to start Windows 2000 in Safe mode3. Edit the registryYou must edit the key HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services and remove the wink[random characters].exe subkey after you write down the exact name of the wink file.

CAUTION: We strongly recommend that you back up the system registry before you make any changes. Incorrect changes to the registry could result in permanent data loss or corrupted files. Please make sure that you modify only the keys that are specified. Please see the document How to back up the Windows registry before you proceed.

a. Click Start, and click Run. The Run dialog box appears.

b. Type regedit and then click OK. The Registry Editor opens.

c. Navigate to the following key:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services

d. In the left pane, under the \Services key, look for the following subkey:

\Wink[random characters]

e. Write down the exact file name of the Wink[random characters].exe file

f. Delete the Wink[random characters] subkey.

g. Navigate to the following key:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

h. In the right pane, look for the following values, and delete them if they exist:

Wink[random characters] %System%\Wink[random characters].exe

WQK %System%\Wqk.exe

NOTE: They probably will not exist on Windows 2000/XP-based computers, but you should check for them anyway.

i. Click Registry, and click Exit.

4. Configure Windows to show all filesDo not skip these steps:a. Start Windows Explorer.

b. Click the Tools menu, and click " Folder options. "

c. Click the View tab.

d. Uncheck " Hide file extensions for known file types. "

e. Uncheck " Hide protected operating system files, " and under the " Hidden files " folder, click " Show hidden files and folders. "

f. Click Apply, and then click OK.

5. Delete the actual Wink[random characters] fileUsing Windows Explorer, open the C:\Winnt\System folder and locate the Wink[random characters].exe file. (Depending on your system settings, the .exe extension may not be displayed.)

NOTE: If you have Windows installed to a location other than C:\Windows, make the appropriate substitution.

6. Empty the Recycle BinRight-click the Recycle Bin on the Windows desktop, and click Empty Recycle Bin.

7. Run the Intelligent UpdaterDouble-click the file that you downloaded in Step 1. Click Yes or OK if you are prompted.

8. Restart the computerShut down the computer, and turn off the power. Wait 30 seconds, and then restart it.

CAUTION: This step is very important. Reinfection will occur if this is not followed.

Allow the computer to start normally. If any files are detected as infected by W32.Klez.H@mm or W32.Klez.gen@mm, Quarantine them. Some of the files that you may find are Luall.exe, Rescue32.exe, and Nmain.exe.

9. Scan with Norton AntiVirus (NAV) from the command lineBecause some NAV files were damaged by the worm, you must scan from the command line.

NOTE: These instructions are only for consumer versions of NAV. The file Navw32.exe is not part of Enterprise versions of NAV such as NAVCE. The NAVCE command line scanner, Vpscan.exe, will not remove the worm.

a. Click Start, and click Run.

b. Type--or copy and paste--the following, and then click OK:

NAVW32.EXE /L /VISIBLE

c. Allow the scan to run. Quarantine any additional files that are detected.

10. Reinstall NAV

NOTE: If you are using NAV 2002 on Windows XP, this may not be possible on all systems. You can, however, try the following: Open the Control Panel, double-click Administrative Tools, and then double-click Services. In the list, select Windows Installer. Click Action, and then click Start.

Follow the instructions in the document How to restore Norton AntiVirus after removing a virus to reinstall NAV.

11. Restart the computer and scan againa. Shut down the computer, and turn off the power. Wait 30 seconds and then restart it.

CAUTION: This step is very important. Reinfection will occur if this is not followed.

b. Run LiveUpdate and download the most current virus definitions.

c. 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.

d. Run a full system scan. Quarantine any files that are detected as infected by W32.Klez.H@mm or W32.Klez.gen (AT) mm (DOT)

Additional information:

Information for Novell users

Novell servers are not directly vulnerable, but a Novell client running under Windows can access the Novell server and execute the file from there (using a login script or other means), which can spread the virus further.

Revision History:

May 2, 2002.Added Additional information for Novell usersAdded additional alias information

Write-up by: Neal Hindocha