Discovered: June 04, 2003
Updated: February 13, 2007 12:02:04 PM
Also Known As: Win32.Bugbear.B [Computer Asso, W32/Bugbear.b@MM [McAfee], PE_BUGBEAR.B [Trend], W32/Bugbear-B [Sophos], I-Worm.Tanatos.b [Kaspersky], W32/Bugbear.B [Panda], Win32/Bugbear.B@mm [RAV]
Type: Worm, Virus
Systems Affected: Windows
CVE References: CVE-2001-0154
W32.Bugbear.B@mm worm is:
- A variant of W32.Bugbear@mm.
- A mass-mailing worm that also spreads through network shares.
- Polymorphic and also infects a select list of executable files.
- Possesses keystroke-logging and Backdoor capabilities.
- Attempts to terminate the processes of various antivirus and firewall programs.
The worm uses the Incorrect MIME Header Can Cause IE to Execute E-mail Attachment vulnerability to cause unpatched systems to auto-execute the worm when reading or previewing an infected message.
In addition, the worm contains routines that specifically affect financial institutions. This functionality will cause the worm to send sensitive data to one of 10 hard-coded, public Internet e-mail addresses. The sent information includes cached passwords and key-logging data.
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.
- If you believe your computer may already be infected with W32.Bugbear.B@mm because your antivirus software does not work, scan your system over the Internet with Symantec Security Check.
- Symantec has recorded a Web cast discussing information about W32.Bugbear.B@mm. You can access the Web cast at: https://www76.placeware.com/cc/symantec/view?id=bugb2. Input your name and click View.
Security Response has received many submissions of corrupted W32.Bugbear.B@mm samples. A specific detection for this type of infected file has been added as W32.Bugbear.B.Dam. This detection is available in virus definitions dated June 6, 2003. Be sure to delete the files detected as W32.Bugbear.B.Dam.
Antivirus Protection Dates
- Initial Rapid Release version June 05, 2003
- Latest Rapid Release version December 01, 2019 revision 018
- Initial Daily Certified version June 05, 2003
- Latest Daily Certified version December 19, 2019 revision 021
- Initial Weekly Certified release date June 05, 2003
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
When W32.Bugbear.B@mm runs, it copies itself to the \Startup folder as a filename, which is composed of a few characters, such as ????.exe, where the question mark symbol (?) represents the letters that the worm chooses.
For example, the worm may copy itself as:
- C:\Windows\Start Menu\Programs\Startup\Cyye.exe when it runs on a Windows 95/98/Me-based system.
- C:\Documents and Settings\<current user name>\Start Menu\Programs\Startup\Cti.exe when it runs on a Windows NT/2000/XP-based system.
When the mass-mailing routine runs, it does the following:
- Searches for the email addresses in the current Inbox, as well as in the files with the following extensions:
- Retrieves the current user's email address and SMTP server from the registry key:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Internet Account Manager\Accounts
- Uses its own SMTP engine to send itself to all the email addresses it finds. As part of the routine, the worm spoofs the From: address.
The worm can reply or forward an existing message, or create a new message with one of the following subject lines:
- Payment notices
- Just a reminder
- Correction of errors
- history screen
- I need help about script!!!
- Please Help...
- Membership Confirmation
- Get a FREE gift!
- Today Only
- New Contests
- Lost & Found
- bad news
- click on this!
- Market Update Report
- empty account
- My eBay ads
- 25 merchants and rising
- CALL FOR INFORMATION!
- new reading
- Sponsors needed
- SCAM alert!!!
- its easy
- free shipping!
- Daily Email Reminder
- Tools For Your Online Business
- New bonus in your cash account
- Your Gift
- $150 FREE Bonus!
- Your News Alert
- Get 8 FREE issues - no risk!
For the attachment filename, the worm uses filenames in the My Documents folder location, which have one of the following extensions:
Then, the filename is concatenated with one of the following extensions:
In addition, the filename can consist of one of the following words:
The content type of the message is matched to the file type, and can be one of the following:
Finally, the email message may be composed with or without using the Incorrect MIME Header Can Cause IE to Execute E-mail Attachment vulnerability to automatically execute on a vulnerable system.
Local and network file infection
The worm will also infect the files on the local and network shares, which match the following filenames. The worm appends itself and is polymorphic.
- Internet Explorer\iexplore.exe
- adobe\acrobat 5.0\reader\acrord32.exe
- Windows Media Player\mplayer2.exe
- Outlook Express\msimn.exe
- Adobe\Acrobat 4.0\Reader\AcroRd32.exe
- MSN Messenger\msnmsgr.exe
- Zone Labs\ZoneAlarm\ZoneAlarm.exe
- Lavasoft\Ad-aware 6\Ad-aware.exe
Network share infection
The worm enumerates all the network shares and computers and attempts to copy itself to those shares. Also, the worm attempts to copy itself to the Windows Startup folder located on remote systems.
The worm does not differentiate between computers and printers. Thus, the worm will inadvertently attempt to queue itself as a print job on network-shared printers.
The worm drops a keylogger as a randomly named DLL in the \Windows\System folder. The file is 5,632 bytes in size and is detected as PWS.Hooker.Trojan. The worm creates additional encrypted files in the Windows and \Windows\System folders with randomly named filenames, and with the extensions .dll or .dat. These files store configuration information and encrypted keystrokes that the keylogger records. Further, the worm will log the text of the foreground window and data stored on the clipboard.
These data files are not malicious and may be deleted.
This key logger data file will be sent to one of the following email addresses every two hours, or when the log file is greater than 25,000 bytes:
When sending the key log file, the worm first disables auto-dialing through the registry to avoid arousing suspicion if you are currently not connected. Once the worm has completed sending the key log file, the worm restores the original setting.
W32.Bugbear.B@mm has functionality that specifically targets financial institutions. The worm contains a large list (over one thousand) of targeted bank domain names from around the world.
If W32.Bugbear.B@mm determines that the default e-mail address of the local system belongs to a banking company, in addition to sending the above key log file, the worm will also send cached dial-up networking passwords to the creator of the worm.
This information is sent to one of the following email addresses every two hours, or when the log file is greater than 25,000 bytes:
Therefore, banking institutions may be considered to be at greater risk.
The worm attempts to terminate security product processes that match the following names:
The worm also opens a listening port on port 1080. The worm's creator can connect to this port and perform the following actions:
- Delete files.
- Terminate processes.
- List processes and deliver the list to the worm's creator.
- Copy files.
- Start processes.
- List files and deliver the list to the worm's creator.
- Deliver intercepted keystrokes to the worm's creator in an encrypted form. This action could release confidential information typed on a computer (passwords, login details, and so on).
- Deliver the system information to the worm's creator in the following form:
- User: <user name>
- Processor: <type of processor used>
- Windows version: <Windows version, build number>
- Memory information: <Memory available, and so on>
- Local drives, their types (for example, fixed/removable/RAM disk/CD-ROM/remote), as well as their physical characteristics.
- List the network resources and their types and deliver the list to the worm's creator.
Symantec Gateway Security
On June 6, 2003, Symantec released an update for Symantec Gateway Security, via LiveUpdate.
On June 5, 2003, Symantec released Intruder Alert 3.5/3.6 Integration Policy for NetProwler 3.5x SU26.
On June 5, 2003, Symantec released NetProwler 3.5.1 Security Update 26 , which includes a detection for W32.Bugbear.B@mm.
To specifically detect this threat as W32.Bugbear.B@mm, Symantec recommends that you use a Symantec ManHunt product to activate the HYBRID MODE function and apply the following custom rules.
NOTE : Each signature should be on a single line. It has been broken up for the purposes of formatting on the Web site.
alert tcp any any -> any 25 (msg:"BugBear B SMTP Worm Propagation"; content:"CwEGAAAgAQAAEAAAAOAGACABCAAA8AYAABAIAAAAQAAAEAAAAAIAAAQAAAAA";)
alert tcp any any -> any 139 (msg:"BugBear B Network Worm Propagation"; content:"|0B010600002001000010000000E006002001080000F006000010080000004000001000000002
alert tcp any any -> any 445 (msg:"BugBear B Network Worm Propagation"; content:"|0B010600002001000010000000E006002001080000F006000010080000004000001000000002
These signatures will trigger on propagation of the worm during a network infection and over SMTP. For more information on how to create custom signatures, refer to "Symantec ManHunt Administrative Guide: Appendix A Custom Signatures for HYBRID Mode."
Further, the Symantec ManHunt Protocol Anomaly currently detects the Backdoor activity associated with W32.Bugbear.B@mm as "SOCKS Malformed Data." To specifically detect this Backdoor activity as W32.Bugbear.B@mm, Symantec recommends that you also apply the following custom rules.
NOTE : Use discretion when applying these Backdoor signatures, as they may be prone to false positives.
alert tcp any any -> any 1080 (msg: "BugBear B Backdoor Attack"; content: "|3b|p"; offset: 20; depth: 2; dsize:>21; )
alert tcp any any -> any 1080 (msg: "BugBear B Backdoor Attack"; content: "|3b|e"; offset: 20; depth: 2; dsize:>21; )
alert tcp any any -> any 1080 (msg: "BugBear B Backdoor Attack"; content: "|3b|f"; offset: 20; depth: 2; dsize:>21; )
alert tcp any any -> any 1080 (msg: "BugBear B Backdoor Attack"; content: "|3b|s"; offset: 20; depth: 2; dsize:>21; )
alert tcp any any -> any 1080 (msg: "BugBear B Backdoor Attack"; content: "|3b|c"; offset: 20; depth: 2; dsize:>21; )
alert tcp any any -> any 1080 (msg: "BugBear B Backdoor Attack"; content: "|3b|o"; offset: 20; depth: 2; dsize:>21; )
alert tcp any any -> any 1080 (msg: "BugBear B Backdoor Attack"; content: "|3b|k"; offset: 20; depth: 2; dsize:>21; )
alert tcp any any -> any 1080 (msg: "BugBear B Backdoor Attack"; content: "|3b|d"; offset: 20; depth: 2; dsize:>21; )
alert tcp any any -> any 1080 (msg: "BugBear B Backdoor Attack"; content: "|3b|r"; offset: 20; depth: 2; dsize:>21; )
alert tcp any any -> any 1080 (msg: "BugBear B Backdoor Attack"; content: "|3b|h"; offset: 20; depth: 2; dsize:>21; )
alert tcp any any -> any 1080 (msg: "BugBear B Backdoor Attack"; content: "|3b|i"; offset: 20; depth: 2; dsize:>21; )
alert tcp any any -> any 1080 (msg: "BugBear B Backdoor Attack"; content: "|3b|z"; offset: 20; depth: 2; dsize:>21; )
alert tcp any any -> any 1080 (msg: "BugBear B Backdoor Attack"; content: "|3b|y"; offset: 20; depth: 2; dsize:>21; )
alert tcp any any -> any 1080 (msg: "BugBear B Backdoor Attack"; content: "|3b|t"; offset: 20; depth: 2; dsize:>21; )
Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":
- Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
- 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.
- Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
- Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
- Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
- Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
- If a 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.
- Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
- Isolate compromised computers quickly to prevent threats from spreading further. 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.
- If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
- For further information on the terms used in this document, please refer to the Security Response glossary.
Removal using the W32.Bugbear.B@mm Removal Tool
Symantec Security Response has created a tool to remove W32.Bugbear.B@mm, which is the easiest way to remove this threat.
As an alternative to using the removal tool, you can manually remove this threat.
The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.
- Disable System Restore (Windows Me/XP).
- Update the virus definitions.
- Restart the computer in Safe mode (Windows 95/98/Me/2000/XP) or VGA mode (Windows NT).
- Ensure that all network connections are not open, including cable and DSL.
- Run a full system scan and repair or delete all the files detected as W32.Bugbear.B@mm.
For specific details on each of these steps, read the following instructions.
1. Disabling System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.
Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.
Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.
For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:
- "How to disable or enable Windows Me System Restore"
- "How to turn off or turn on Windows XP System Restore"
For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article, "Antivirus Tools Cannot Clean Infected Files in the _Restore Folder ," Article ID: Q263455.
2. Updating the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:
- Running LiveUpdate, which is the easiest way to obtain virus definitions: These virus definitions are posted to the LiveUpdate servers once each week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, refer to the Virus Definitions (LiveUpdate).
- Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to the Virus Definitions (Intelligent Updater).
The Intelligent Updater virus definitions are available: Read "How to update virus definition files using the Intelligent Updater" for detailed instructions.
3. Restarting the computer in Safe mode or VGA mode
- For Windows 95, 98, Me, 2000, or XP users, restart the computer in Safe mode. For instructions, refer to the document, "How to start the computer in Safe Mode."
- For Windows NT 4 users, restart the computer in VGA mode.
4. Ensuring that all network connections are not open, including cable and DSL
If you are on a network or have a full-time connection to the Internet, such as a DSL or cable modem, make sure that the computer is disconnected from the network and the Internet. Disable or password-protect file sharing, or set the shared files to Read Only, before reconnecting the computers to the network or the Internet.
Because this worm spreads by using shared folders on networked computers, to ensure that the worm does not re-infect the computer after it has been removed, Symantec suggests sharing with Read Only access or by using password protection. For instructions on how to do this, refer to your Windows documentation, or the document, "How to configure shared Windows folders for maximum network protection ."
5. Scanning for and repairing or deleting the infected files
- Start your Symantec antivirus program and make sure that it is configured to scan all the files.
- For Norton AntiVirus consumer products: Read the document, "How to configure Norton AntiVirus to scan all files."
- For Symantec AntiVirus Enterprise products: Read the document, "How to verify that a Symantec Corporate antivirus product is set to scan all files."
- Run a full system scan.
- If any files are detected as infected with W32.Bugbear.B@mm, click Repair. For files that cannot be repaired, Click Delete.
Writeup By: Eric Chien