UPDATE (2002-12-03 14:00 GMT)
F-Secure is downgrading the Bugbear/Tanatos email worm from Level 1 to Level 2 as it is not spreading as fast as before.
UPDATE (2002-10-02 13:30 GMT)
F-Secure is upgrading the Bugbear/Tanatos email worm to Level 1 as it continues to spread rapidly. Currently it is the most widespread virus in the world together with Klez. For more information, see Global Bugbear worm Information Center: http://www.europe.f-secure.com/bugbear/
When run, the worm copies itself to Windows System directory with a random name (JFMV.EXE for example) and adds a startup key for this file to the Registry:
It also drops a keylogging component as a DLL file with a randomly-generated name (ZLQPUPP.DLL for example) to Windows System folder. The worm also creates 2 more DLL files and stores some encrypted data there. The worm creates 2 randomly named DAT files in root Windows folder too.
The worm's file is a PE EXE (portable executable), 50688 bytes long and it is compressed with UPX file compressor. Bugbear spreads in email messages as an attachment with randomly-generated names and with one or more extensions. Subjects and bodies of infected emails are also different. The mass-mailing routine is quite complex.
The worm has the ability to fake information in email headers, so sometimes the sender's email address gets replaced with another address that the worm finds on an infected system.
The worm's messages can contain IFrame exploit that allows it to run automatically on some computers when an infected email is viewed (for example, with Outlook and IE 5.0 or 5.01). This vulnerability is fixed and a patch for it is available on the Microsoft site:
Bugbear worm looks for email addresses in INBOX (Netscape incoming email database) and in files with the following extensions:
Sometimes the worm picks up email messages from infected user's database and sends them out with its copy attached. Also the worm can place contents of a random text file from an infected hard drive to an infected message's body. It can send itself in a message with one of the following subjects:
- Get 8 FREE issues - no risk!
- Your News Alert
- $150 FREE Bonus!
- Your Gift
- New bonus in your cash account
- Tools For Your Online Business
- Daily Email Reminder
- free shipping!
- its easy
- SCAM alert!!!
- Sponsors needed
- new reading
- CALL FOR INFORMATION!
- 25 merchants and rising
- My eBay ads
- empty account
- Market Update Report
- click on this!
- bad news
- Lost & Found
- New Contests
- Today Only
- Get a FREE gift!
- Membership Confirmation
- Please Help...
- I need help about script!!!
- history screen
- Correction of errors
- Just a reminder
- Payment notices
The worm doesn't send itself to addresses that contain the following strings (to avoid bounces and other unwanted events):
Bugbear can send itself as an attachment with with double extensions. The first extension can be one of the following:
It sets the content type of an infected attachment according to the above file types. Content type can be one of the following:
The second extension of an infected attachment can be one of the following:
Also the worm can 'borrow' the name for its attachment from one of files on an infected hard drive and then to add an executable extension to it, for example it can send itself as AGREEMENT.DOC.PIF file. The name of the infected attachment can contain one of the following strings:
Propagation (Local Area Network)
Bugbear has local network spreading capabilities. The worm enumerates network resources and tries to locate \Start Menu\Programs\Startup\ folder on remote systems. If such path is found, the worm copies itself there with a random name. When a remote system is restarted, the worm's file gets control and infects a system.
The worm continuously looks for and terminates processes with the below-given names:
The worm uses separate routines for process killing on Windows 9x- and NT-based systems. In most cases the worm effectively disables security and anti-virus software that fail to detect it entering a system.
Bugbear worm also listens to port 36794 and can provide access to an infected system and the network it is connected to via an internal backdoor component. The backdoor component allows an attacker to access an infected system through a web-based interface. The worm generates HTML pages on-the-fly when an attacker browses directories on an infected remote computer.
It contains several icons that it uses to identify the type of remote drives and files. The backdoor component also allows to browse shared network resources that an infected computer has access to. The worm also uses icons to identify network resources.
Bugbear allows an attacker to get information about the infected system: operating system, processor type, fixed and network drives.
The worm has password stealing capabilities. It installs a keylogging component to a system, records keystrokes and saves them into a file. Then it sends this file to a few email addresses that are stored in encrypted for in the worm's body. The smtp server names that the worm uses to send the files are also stored in encrypted form in the worm's body.
According to reports, network printers start to print a lot of garbage when the worm infects a network. This might be the side-effect of the worm's attempts to infect a network.