In the last few days thousands of computers all over the world have been infected with this virus. Here's a report from Symantec:

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

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

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

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.

It creates the following value

(random letters) (the worm's file name)

in the registry key

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce

The worm creates four major threads

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.

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.
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 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.

My Norton scans all my e-mail and I received it 5 times in about a 2 hour period yesterday morning. Get a good antivirus such as Norton or MacAfee keep it updated, and running folks. Don't click on any file attached unless you knew the file was coming. Do not install any screensavers you get via e-mail (scr extension) as they are an executable) and of course noe exe or inf files. Delete the thing immediately.

amazing how unsecure windows is

In fact, it does not come with any attachments. I share my PC with my family, and my father got it 10 times in one day :/. Of course, it was detected by NAV.

Big whoop, my norton antivirus updated with auto protect will zap it.

I don't even open emails from people I don't know. If the subject doesn't have my DMusic name or my real name in it I delete it.