Backdoor.Bmbot

SUMMARY

Backdoor.Bmbot is a backdoor Trojan that allows a hacker to gain control of your computer by using Internet Relay Chat (IRC). A false error message is displayed if Backdoor.Bmbot is not executed from the %System% folder.

Protection

• Virus Definitions (LiveUpdate™ Weekly) February 19, 2003
• Virus Definitions (Intelligent Updater) February 18, 2003

Threat Assessment

Wild

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

Damage

• Damage Level: Medium
• Releases Confidential Info: System and network information may be relayed to the hacker.
• Compromises Security Settings: Allows unauthorized access to an infected computer.

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

If Backdoor.Bmbot is not executed from the %System% folder, it does the following:

1. Copies itself as %System%winupdate.exe.
   
   NOTE: %System% is a variable. The Trojan locates the System folder and copies itself to that location. By default, this is C:WindowsSystem (Windows 95/98/Me), C:WinntSystem32 (Windows NT/2000), or C:WindowsSystem32 (Windows XP).
   
2. Adds the value:
   
   Microsoft auto update      winupdate.exe
   
   to the registry key:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
   
   so that the Trojan starts when you start Windows.
   
3. Creates the following registry key and adds multiple values to it:
   
   HKEY_LOCAL_MACHINEWINSOCK_32
   
4. Displays the following message, and then quits:
   
   
   

If Backdoor.Bmbot is executed from the %System% folder, it connects to an IRC server and waits for commands from the hacker to perform the following actions:

• Deliver system and network information to the hacker
• Control the IRC client included in Backdoor.Bmbot
• Delete, download, or execute files
• Update the IRC server address to which the Trojan connects
• Email the Trojan to other people
• Perform HTTP requests
• Perform Denial of Service (DoS) attacks

If Backdoor.Bmbot sends email, the email has the following characteristics:

Attachment: BlueMountaineCard.pif

Subject: Hi, I sent you an eCard from BlueMountain.com

Message: To view your eCard, open the attachment. If you have any comments or questions, please visit http://www.bluemountain.com/customer/index.pd Thanks for using BlueMountain.com.

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

These instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Update the virus definitions.
2. Run a full system scan and delete all the files detected as Backdoor.Bmbot.
3. Delete the value:
   
   Microsoft auto update
   
   from the registry key:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   

For specific details on each of these procedures, read the following instructions.

1. 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 the 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), in the "Protection" section, at the top of this writeup.
• 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), in the "Protection" section, at the top of this writeup.
  
  The 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. Scanning for and deleting the infected files

1. 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."
2. Run a full system scan.
3. If any files are detected as infected with Backdoor.Bmbot, click Delete.

3. Deleting 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 the specified keys only. Read the document, "How to make a backup of the Windows registry," for instructions.

1. Click Start, and then click Run. (The Run dialog box appears.)
2. Type regedit
   
   Then click OK. (The Registry Editor opens.)
   
3. Navigate to the key:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
4. In the right pane, delete the value:
   
   Microsoft auto update
   
5. Exit the Registry Editor.