BAT.Beckow.B@mm

SUMMARY

BAT.Beckow.B@mm is a worm that sends itself to all addresses in the Microsoft Outlook Address Book. It also propagates through IRC. It attempts to copy itself to drive A, overwrite .reg, .vbs, .bat, .ifk, .pif, and .lnk files, and delete files that are associated with several antivirus programs.

Protection

• Virus Definitions (LiveUpdate™ Weekly) June 26, 2002
• Virus Definitions (Intelligent Updater) June 25, 2002

Threat Assessment

Wild

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

Damage

• Damage Level: Medium
• Payload: Overwrites and attempts to delete files. Sends itself to all recpients in the Outlook Address Book
• Large Scale E-mailing: Sends itself to all recpients in the Outlook Address Book
• Deletes Files: Attempts to delete files that are associated with several antivirus programs
• Modifies Files: Overwrites .reg, .vbs, .bat, .ifk, .pif, and .lnk files. Win.ini. System.ini.
• Compromises Security Settings: Attempts to delete files associated with several antivirus programs.

Distribution

• Distribution Level: High
• Name of Attachment: marcos.BAT
• Size of Attachment: 9612 bytes

TECHNICAL DETAILS

When BAT.Beckow.Worm runs, it does the following:

It creates these files in the folder that contains the worm:

• Anderson.reg
• Denilson.vbs
• Vx.vbs (the primary worm file)

It also creates the following files:

• C:This_Is_Just_A_Simple_Worm_By_Galaxynet_IRC_#VXRonaldo.jpg.bat (the primary worm file)
• C:Lucio.vbs (the worm component that performs the email routine)
• C:Marcos.bat (the primary worm file)
• \%Windows%Dida.bat
• \%Windows%Kaka.bat
• \%Windows%Carlos.vbs
• \%Windows%Chmxc.bat
• \%Windows%Paulista.bat
• \%Windows%Silva.bat
• \%Windows%SystemWini.bat (the primary worm file)
• \%Windows%Startm~1ProgramsStartUpKleberson.bat (the primary worm file)
• A:Cafu.bat (the primary worm file)

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

The worm then sends itself to all contacts in the Outlook Address Book. The email message has the following characteristics:

Subject: (The subject line is empty.)
Message: Trashing Turkey Tactics!! Fresh From Brazil Coach!!
Attachment: Marcos.bat

The worm then renames the C:Autoexec.bat file to C:Cafu.bat and overwrites .reg, .vbs, .bat, .ifk, .pif, and .lnk files in various locations on the computer.

This worm is also an IRC worm. It attempts to find an mIRC installation on the computer and replace the Script.ini file with a script that propagates the worm. The name of the attachment that it tries to send to IRC users is C:This_Is_Just_A_Simple_Worm_By_Galaxynet_IRC_#VXonaldo.jpg.bat.

To evade detection, the worm tries to delete the following files from various antivirus software:

• C:Prlandgra~1Kasper~1Avp32.exe
• C:Prlandgra~1Norton~1*.exe
• C:Prlandgra~1Trojan~1Tc.exe
• C:PrlandgraNorton~1S32integ.dll
• C:PrograF-Prot95Fpwm32.dll
• C:Progra McafeeScan.dat
• C:PrlandgraTbavTbav.dat
• C:PrograAvpersonalAntivir.vdf
• C:Tbavw95Tbscan.sig

NOTE: The previous paths are hardcoded into the worm.

Due to bugs in the worm, some functions do not work correctly; however, the mass-mailing function does work.

Finally, this worm displays the following message:

Brazil shall win the World Cup 2002!!

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

1. Update the virus definitions, run a full system scan. Record the names of any .reg, .vbs, .bat, .ifk, .pif, or .lnk, files that were overwritten by the worm, and delete all files that Norton AntiVirus (NAV) detects as BAT.Beckow.B@mm.
2. Rename C:Cafu.bat back to C:Autoexec.bat (Windows 95/98/Me only).
3. Replace overwritten files from a clean backup.

For details on how to do this, read the following instructions.

To scan with Norton AntiVirus and delete the infected files:

1. Obtain the most recent virus definitions. There are two ways to do this:
   • Run LiveUpdate, which 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.
   • NAV Consumer products: Read the document How to configure Norton AntiVirus to scan all files.
   • NAV Enterprise products: Read the document How to verify a Symantec Corporate antivirus product is set to scan All Files.
3. Run a full system scan.
4. Write down the names and locations of any files that NAV detects as BAT.Beckow.B@mm, and then delete them.
5. Replace the deleted .reg, .vbs, .bat, .ifk, .pif, and .lnk, files (other than those that were dropped by the worm) from a clean backup, or reinstall them. For a list of the files that the worm dropped (copied to the system), read the technical description section of this document.

To rename C:Cafu.bat back to C:Autoexec.bat (Windows 95/98/Me only):

1. Using Windows Explorer, locate C:Cafu.bat.
2. Right-click the file, and then click Rename.
3. Change the name to Autoexec.bat.
4. Click anywhere outside the Rename field to save the changes.