Symantec Security Response Bugbear Virus

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W32.Bugbear@mm

Discovered on: September 30, 2002

Last Updated on: October 2, 2002 06:17:34 PM PDT

NOTE: Due to an increased rate of submissions, Symantec Security Response has upgraded this threat from a Category 3 to a Category 4 as of October 2, 2002.

W32.Bugbear@mm is a mass-mailing worm. It can also spread through network shares. It has keystroke-logging and backdoor capabilities. The worm also attempts to terminate the processes of various antivirus and firewall programs.

Security Response has seen that because the worm does not properly handle the network resource types, it may flood shared printer resources, which causes them to print garbage or disrupt their normal functionality.

It is written in the Microsoft Visual C++ 6 programming language and is compressed with UPX v0.76.1-1.22.

Also Known As: W32/Bugbear-A [Sophos], WORM_BUGBEAR.A [Trend], Win32.Bugbear [CA], W32/Bugbear@MM [McAfee], I-Worm.Tanatos [AVP], W32/Bugbear [Panda], Tanatos [F-Secure]
Type: Worm
Infection Length: 50,688 bytes
Systems Affected: Windows 95, Windows 98, Windows NT, Windows 2000, Windows XP, Windows Me
Systems Not Affected: Macintosh, Unix, Linux
CVE References: CVE-2001-0154

• Virus Definitions (Intelligent Updater) *

September 30, 2002

• Virus Definitions (LiveUpdate™) **

September 30, 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: Moderate

Threat Metrics
Wild: High			Damage: Medium			Distribution: High

Damage

• Payload:
  • Large scale e-mailing: Attemps to mass-mail to addresses harvested from a compromised host using it's own SMTP engine

  • Compromises security settings: May allow unauthorized access to compromised machines. Attempts to terminate processes of various antivirus and firewall programs.

Distribution

• Subject of email: Variable
• Name of attachment: Variable, with double extension ending in .exe, .scr, or .pif
• Size of attachment: 50,688 bytes
• Ports: 36794
• Shared drives: Attempts to connect to available network resources

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

It copies itself as %system%\????.exe, where ? represents letters that are chosen by the worm.

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 copies itself to the \Startup folder as ???.exe, where ? represents letters that are chosen by the worm. For example,

• It may copy itself as C:\Windows\Start Menu\Programs\Startup\Cuu.exe when it runs on a Windows 95/98/Me-based system
• It may copy itself as C:\Documents and Settings\<current user name>\Start Menu\Programs\Startup\Cti.exe when it runs on a Windows NT/2000/XP-based system.

It creates three encrypted .dll files in the %system% folder and two encrypted .dat files in the %windir% folder. One of the dropped .dll files is used by the worm to install hook procedures into a hook chain to monitor the system for any keyboard and mouse messages. The keyboard hook procedures process the messages and pass the hook information to the next hook procedure in the current hook chain. This allows the worm to intercept keystrokes. The installed .dll is 5,632 bytes in size and is detected by Symantec antivirus product as PWS.Hooker.Trojan.

Files that are not detected by Symantec antivirus product are not malicious. The worm uses them to store internal configuration information in an encrypted form. You should delete these files manually. For example, the worm may create the following files:

• %system%\Iccyoa.dll
• %system%\Lgguqaa.dll
• %system%\Roomuaa.dll
• %windir%\Okkqsa.dat
• %windir%\Ussiwa.dat

NOTES: %windir% is a variable. The worm locates the \Windows folder (by default this is C:\Windows or C:\Winnt) and creates files in that location.

It creates the following value

<random letters> <the worm's file name>

in the registry key

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce

NOTE: Normally, the operating system removes values from this key as soon as the programs refered to by these values are launched during startup. In this case the worm recreates the value so that it starts each time that you start Windows.

The worm creates four major threads. The first one activates its payload every 30 seconds to stop the following processes if they are running:

• Zonealarm.exe
• Wfindv32.exe
• Webscanx.exe
• Vsstat.exe
• Vshwin32.exe
• Vsecomr.exe
• Vscan40.exe
• Vettray.exe
• Vet95.exe
• Tds2-Nt.exe
• Tds2-98.exe
• Tca.exe
• Tbscan.exe
• Sweep95.exe
• Sphinx.exe
• Smc.exe
• Serv95.exe
• Scrscan.exe
• Scanpm.exe
• Scan95.exe
• Scan32.exe
• Safeweb.exe
• Rescue.exe
• Rav7win.exe
• Rav7.exe
• Persfw.exe
• Pcfwallicon.exe
• Pccwin98.exe
• Pavw.exe
• Pavsched.exe
• Pavcl.exe
• Padmin.exe
• Outpost.exe
• Nvc95.exe
• Nupgrade.exe
• Normist.exe
• Nmain.exe
• Nisum.exe
• Navwnt.exe
• Navw32.exe
• Navnt.exe
• Navlu32.exe
• Navapw32.exe
• N32scanw.exe
• Mpftray.exe
• Moolive.exe
• Luall.exe
• Lookout.exe
• Lockdown2000.exe
• Jedi.exe
• Iomon98.exe
• Iface.exe
• Icsuppnt.exe
• Icsupp95.exe
• Icmon.exe
• Icloadnt.exe
• Icload95.exe
• Ibmavsp.exe
• Ibmasn.exe
• Iamserv.exe
• Iamapp.exe
• Frw.exe
• Fprot.exe
• Fp-Win.exe
• Findviru.exe
• F-Stopw.exe
• F-Prot95.exe
• F-Prot.exe
• F-Agnt95.exe
• Espwatch.exe
• Esafe.exe
• Ecengine.exe
• Dvp95_0.exe
• Dvp95.exe
• Cleaner3.exe
• Cleaner.exe
• Claw95cf.exe
• Claw95.exe
• Cfinet32.exe
• Cfinet.exe
• Cfiaudit.exe
• Cfiadmin.exe
• Blackice.exe
• Blackd.exe
• Avwupd32.exe
• Avwin95.exe
• Avsched32.exe
• Avpupd.exe
• Avptc32.exe
• Avpm.exe
• Avpdos32.exe
• Avpcc.exe
• Avp32.exe
• Avp.exe
• Avnt.exe
• Avkserv.exe
• Avgctrl.exe
• Ave32.exe
• Avconsol.exe
• Autodown.exe
• Apvxdwin.exe
• Anti-Trojan.exe
• Ackwin32.exe
• _Avpm.exe
• _Avpcc.exe
• _Avp32.exe

The worm determines which version of the operating system is running and uses different routines to accomplish its task.

The second thread is responsible for the mass-mailing payload. It searches for email addresses in the current inbox and in files that have these extensions:

• .mmf
• .nch
• .mbx
• .eml
• .tbb
• .dbx
• .ocs

It retrieves the current user's email address and SMTP server from the registry key

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Internet Account Manager\Accounts

It then uses its own SMTP engine to send itself to all email addresses that it finds. The worm also has the ability to construct addresses for the From: field from information harvested off the infected users system. For example, the worm may find the addresses a@a.com, b@b.com and c@c.com. Then the worm could create an email addressed to a@a.com and spoof the from address to report c@b.com. The spoofed address can also be a valid email address found on the system.

In addition to the following list of subjects, the worm can create a new message as a reply to or forward of an existing message on the infected system.

• Greets!
• Get 8 FREE issues - no risk!
• Hi!
• Your News Alert
• $150 FREE Bonus!
• Re:
• Your Gift
• New bonus in your cash account
• Tools For Your Online Business
• Daily Email Reminder
• News
• free shipping!
• its easy
• Warning!
• SCAM alert!!!
• Sponsors needed
• new reading
• CALL FOR INFORMATION!
• 25 merchants and rising
• Cows
• My eBay ads
• empty account
• Market Update Report
• click on this!
• fantastic
• wow!
• bad news
• Lost & Found
• New Contests
• Today Only
• Get a FREE gift!
• Membership Confirmation
• Report
• Please Help...
• Stats
• I need help about script!!!
• Interesting...
• Introduction
• various
• Announcement
• history screen
• Correction of errors
• Just a reminder
• Payment notices
• hmm..
• update
• Hello!

The worm reads the contents of the Personal value in the registry key

SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders

and lists the files that are stored at that location (which by default is C:\My Documents on Windows 95/98/Me and C:\Documents and Settings\<User Name>\My Documents on Windows NT/2000/XP). These retrieved file names may be used to compose file name of the viral attachment. In addition, the file name may consist of one of the following words:

• readme
• Setup
• Card
• Docs
• news
• image
• images
• pics
• resume
• photo
• video
• music
• song
• data

The file name's extension is chosen from the following list:

• .scr
• .pif
• .exe

If the worm used a file name that it retrieved from the My Documents folder, it will modify the content type of the message to match the file's extension. The list of the analysed extensions is:

• .reg
• .ini
• .bat
• .diz
• .txt
• .cpp
• .html
• .htm
• .jpeg
• .jpg
• .gif
• .cpl
• .dll
• .vxd
• .sys
• .com
• .exe
• .bmp

The content type of the composed message is modified to one of the following:

• text/html
• text/plain
• application/octet-stream
• image/jpeg
• image/gif

The email message can be composed with or without the use of the Incorrect MIME Header Can Cause IE to Execute E-mail Attachment vulnerability to autoexecute on a vulnerable system. Please go to http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS01-020.asp for additional information.

The third thread that the worm creates is a backdoor routine. It opens port 36794 and listens for commands from the hacker. The commands permit the worm to perform the following actions:

• Delete files.
• Terminate processes.
• List processes and deliver the list to the hacker.
• Copy files.
• Start processes.
• List files and deliver the list to the hacker.
• Deliver intercepted keystrokes to the hacker (in an encrypted form). This may release confidential information that typed on a computer (passwords, login details, and so on).
• Deliver the system information to the hacker in the following form:
  • User: <user name>
  • Processor: <type of processor used>
  • Windows version: <Windows version, build number>
  • Memory information: <Memory available, etc.>
  • Local drives, their types (e.g., fixed/removable/RAM disk/CD-ROM/remote), and their physical characteristics
• List network resourses and their types, and deliver the list to the hacker.

If the operating system is Windows 95/98/Me, the worm attempts to obtain access to the password cache on the local computer. The cached passwords include modem and dial-up passwords, URL passwords, share passwords, and others. This is done using an officially undocumented function--WNetEnumCachedPasswords--that exists only in Windows95/98/Me versions of the Mpr.dll file.

One of the commands permits the Trojan component to deliver data using HTTP port 80. The results of the backdoor activity may be represented in the form of HTML pages. This gives a hacker a convienient way to browse the compromised computer resources.

The fourth worm thread replicates across the network. To do this, the worm lists all of the resources in the network. If it locates open administrator shares, it attempts to copy itself to the Startup folder of the remote computer. This leads to the infection of the compromised network computers as soon as they are restarted.

Because the worm does not properly handle the network resource types, it may flood shared printer resources, which causes them to print garbage or disrupt their normal functionality.

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.
• 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 W32.Bugbear@mm Removal Tool
This is the easiest way to remove this threat. Symantec Security Response has created a W32.Bugbear@mm Removal Tool. Click here to obtain the tool.

Manual Removal
As an alternative to using the removal tool, you can remove this threat manually.

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. Restart the computer in Safe mode.
3. Run a full system scan, and delete all files that are detected as W32.Bugbear@mm.
4. Delete the value added by the worm from the registry key

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce

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

To update the virus definitions:

NOTE: If the worm is currently active on your computer, you will not be able to run LiveUpdate. In this case, you must download the definitions using the Intelligent Updater.

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 restart the computer in Safe mode:
All Windows 32-bit operating systems, except Windows NT, can be restarted in Safe mode. For instructions on how to do this, read the document How to start the computer in Safe Mode.

To scan for and delete the infected files:

1. Start your Symantec antivirus program, and ensure that it is configured to scan all files.
• Norton AntiVirus consumer products: Read the document How to configure Norton AntiVirus to scan all files.
• Symantec enterprise antivirus products: Read the document How to verify 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.Bugbear@mm, write down the file name and then click Delete.

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 this key:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce

4. In the right pane, locate and delete the line that refers to the file that was detected as infected with W32.Bugbear@mm.
5. Exit the Registry Editor.

Revision History:

• September 30, 2002.
  • Added alias information.
  • Upgraded from Category 2 to Category 3 based on increased rate of submissions.
• October 1, 2002. Provided W32.Bugbear@mm removal tool.
• October 2, 2002.
  • Upgraded from Category 3 to Category 4 based on increased rate of submissions.
  • Updated mailing information to included spoofed from addresses and subject lines pulled from existing email messages found on the infected system.

Write-up by: Yana Liu and Serghei Sevcenco

[Mixer]

This is very serious for those of us that are in charge of networks and can also be a threat to home networks as well.

[Poohbah]

This is very serious

It might also be "vey series," too!

[bonesmccoy]

Thanks... I appreciate the info. The war on terrorism requires improved network tools to identify threats and neutralize their servers.

[Mixer]

This virus was discovered on September 30th...a day that a lot of other same type back door viruses were found. I wonder if these will all tie into something bigger

[TaRaRaBoomDeAyGoreLostToday!]

I auto updated this morn. am I OK?

[TaRaRaBoomDeAyGoreLostToday!]

I will bet in the next 15 posts SOMEONE that is an APPLE user (I like Mac's myself) will say na knee na knee na knee, Apple's don't have to worry about this!

SERIOUSLY THOUGH...

WARNING I HAD a iMac and was hit BAD!!! (meltdown of entire hard drive) So Apple folks best get anti virus protection.

[Mixer]

I auto updated this morn. am I OK?

You should be but it couldnt still hurt to check your PCs to be sure. It only takes about 15-25 minutes depending on the speed of your computer(s)

[bonesmccoy]

Yes, I don't know about you guys, but I began seeing very aggressive attacks on our corporate network back in May 2001 and even called FBI to complain and to investigate if NPIC was doing any good.

[TaRaRaBoomDeAyGoreLostToday!]

Puter is running odd and slow today. So I manually hit LIVE UPDATE even after I had an auto update today. I missed some definitions...so all should hit live update.

[rockrr]

Thanx for the post.
Two points to all to ponder....

1. Most of these viruses are unleashed by opening an attachment to an email. DON'T open attachments unless you know that it is from a trusted source! Actually, my mom knows not to open any attachments even from me unless I send her a notice that it is on its way (just in case my email address gets hacked)

2. Many viruses are spread by accessing your email program's Address Book and sending emails IN YOUR NAME containing the virus to your friends. I would recommend that you create a new entry in your Address Book that contains the name _000 or !000 and lists the email as "user@name.com". This places an invalid email address at the top of your list. Most of the viruses choke on this name and can't get any further. It isn't infallible, but it does offer a bit of insurance.

Be safe

[TaRaRaBoomDeAyGoreLostToday!]

Odd...my icon that usually floats to the right is gone yet all is well and ENABLED. When I did manual update I see it was needed----and quite a download. AND auto live update is enabled.

[Ford Fairlane]

I run esafe - got the following email from them yesterday

----------------------------------------

SPECIAL CSRT BULLETIN

----------------------------------------

New malicious Internet worm spreading fast !!!

eSafe Proactive Content Security In Action

----------------------------------------------------

We would like to inform you that since last night, eSafe Gateway and Mail installed worldwide, has blocked thousands of emails infected with Win32.BugBear Vandal - WITHOUT REQUIRING AN UPDATE! This is achieved with the eSafe new and improved XploitStopper(tm) mechanism that stops cold any email spreading malicious code that attempts to exploit security holes.

Win32.BugBear is a fast spreading Trojan/Worm that can allow hackers full remote control of the infected PC, can monitor all keyboard strokes, steal files and confidential information including passwords, deactivate most desktop anti-virus programs and personal firewalls and perform other malicious activity.

For more information see:

1.Aladdin PR:

http://www.ealaddin.com/news/2002/esafe/bugbear.asp

2. Aladdin CSRT Alert:

http://www.ealaddin.com/home/csrt/valerts2.asp?virus_no=10446

3. C|NET article:

http://news.com.com/2100-1001-960365.html

4. BBC article:

http://news.bbc.co.uk/1/hi/technology/2290153.stm

5. CNN article:

http://europe.cnn.com/2002/TECH/biztech/10/01/tech.bugbear.worm.reut

6. eWeek article:

http://www.eweek.com/article2/0,3959,562163,00.asp

[AdA$tra]

W32.Opaserv.Worm is another one that has been popping up on my enterprise virus protection radar the last couple of days. Not as devistating a payload as bugbear but spreads through drive shares across a network as well as email.

For details:

http://securityresponse.symantec.com/avcenter/venc/data/w32.opaserv.worm.html

Make sure your virus defs are updated. I have a client that had W32.Opaserv.Worm all over his network yesterday due to a failure to update.

[Travis McGee]

Bump to save while I update definitions!

[Mixer]

Thanks for the tips. I do have a question though. Won't the virus simply pass that email address that you created and go onto your next address in the list? What would make it choke that way. I would think it could send to mulitple addresses at once as well?

[stlrocket]

THIS IS NO JOKE!!!!!!!!!!!

I JUST SPENT THE ENTIRE MORNING CLEANING IT OUT!

I NEVER OPEN ANY EXE'S --- BUT THIS CHANGES THEM AND DISGUISES WHAT THE ATTACHMENT IS.

THE PEOPLE WHO MAKE THESE SHOULD BE DRAWN AND QUARTERED IMMEDIATELY!!!!!!!!

[Flyer]

*PING!*

[Dataman]

This is very serious for those of us that are in charge of windows crashware networks and can also be a threat to windows home networks as well.

[Justa]

7. Turn off your computer. Go outside.

[Mixer]

This is very serious for those of us that are in charge of windows crashware networks and can also be a threat to windows home networks as well.

Corporate networks are rarely run on anything else. Sure there are examples of corporate networks without a trace of Windows but very far and few between.