W32.Brid.A@mm

Printer Friendly Page

Discovered: November 04, 2002
Updated: February 13, 2007 11:41:07 AM
Also Known As: PE_BRID.A [Trend], W32/Braid.a@mm [McAfee], W32/Braid-A [Sophos], Win32.Braid.A [CA], I-Worm.Bridex.a [KAV], W32/Bride [Panda], W32/Bridex.A@mm [F-Prot]
Type: Worm
Systems Affected: Windows
CVE References: CVE-2001-0154


Due to a decreased rate of submissions, Symantec Security Response has downgraded this threat from a Category 3 to a Category 2 as of May 5, 2003.

W32.Brid.A@mm is a mass-mailing worm that includes a slightly modified variant of W32.FunLove.4099 . When W32.Brid.A@mm runs, it attempts to insert several files onto the system and mass-mail itself. The worm contains its own SMTP engine, and it attempts to obtain the address of the email server and contact it directly. The email message has the following characteristics:
Subject: [Registered Windows company name]
Attachment : Readme.exe

The worm uses a known exploit in Internet Explorer, Incorrect MIME Header can cause IE to Execute E-mail attachment.

NOTE: Symantec antivirus products will detect the W32.Funlove.4099 virus component with definitions that have dates of November 8, 1999, or later.




If the worm is active in memory, it may stop the processes for various security products, including Norton AntiVirus and Symantec AntiVirus. If this happens, then the process for the worm must be removed from memory before you can use your Symantec antivirus product to remove it. To do this, follow the instructions in the previous section "To remove the value that the worm added to the registry," restart the computer, and then follow the removal instructions from the beginning.

Antivirus Protection Dates

  • Initial Rapid Release version November 04, 2002
  • Latest Rapid Release version March 23, 2017 revision 037
  • Initial Daily Certified version November 04, 2002
  • Latest Daily Certified version March 23, 2017 revision 041
  • Initial Weekly Certified release date November 04, 2002

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Writeup By: Neal Hindocha

Discovered: November 04, 2002
Updated: February 13, 2007 11:41:07 AM
Also Known As: PE_BRID.A [Trend], W32/Braid.a@mm [McAfee], W32/Braid-A [Sophos], Win32.Braid.A [CA], I-Worm.Bridex.a [KAV], W32/Bride [Panda], W32/Bridex.A@mm [F-Prot]
Type: Worm
Systems Affected: Windows
CVE References: CVE-2001-0154


When this worm runs, it first attempts to connect to www.hotmail.com. If the worm is unable to connect, a short delay occurs before the worm continues its malicious actions.

Next, the worm inserts several files onto the system, modifies the Windows registry, runs the slightly modified variant of W32.Funlove.4099 , and emails itself to all contacts in the Microsoft Outlook Address Book.

File Insertion
The worm insert several files on the computer.

It copies these files to the Windows desktop:

  • Help.eml
  • Explorer.exe

Help.eml is a Microsoft Outlook Express file. If this file is opened on an unpatched system, the attachment (which is the worm) runs automatically. This is due to the use of the known exploit, Incorrect MIME Header can cause IE to Execute E-mail attachments.

Explorer.exe is a copy of the worm.

W32.Brid.A@mm also creates these files:
  • %system%\Bride.exe
  • %system%\Msconfig.exe
  • %system%\Regedit.exe
    NOTE: %system% is a variable. The worm locates the System folder and copies itself to that location as %system%\Regedit.exe. By default this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).

%system%\Bride.exe and %system%\Msconfig.exe contains the virus W32.Funlove.4099 . The worm executes this file.

Registry modification
The worm adds the value

regedit %system%\regedit.exe

to the registry key

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

so that the worm runs each time that you start Windows.

It also adds three keys under

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
CurrentVersion\Explorer\RemoteComputer

Virus insertion
This worm contains a slightly modified variant of W32.Funlove.4099 . The worm attempts to execute this virus. The main difference between this variant of the virus and the original W32.Funlove.4099 is the file name that is uses. This variant uses the file name Bride.exe instead of Flcss.exe.

For further information, please refer to the W32.Funlove.4099 write-up.
    NOTE: Symantec antivirus products will detect the W32.Funlove.4099 virus component with definitions that have dates of November 8, 1999, or later.

Email routine
The worm contains its own SMTP engine, and it attempts to find and contact the email server directly.

It attempts to email everyone in the Microsoft Outlook Address Book, as well as any email address it may find inside .htm and .dbx files. The email message that this worm sends will appear as follows:

From: [Registered Windows user name]
    NOTE: The text in the "From:" field may, in some cases, be identical to the text in the "To:" field.

Subject: [Registered Windows company name]
Message Body:
Hello,

Product Name: [Windows Version]
Product ID: [Windows ID]
Product Key: [Key]
Process List: [List of processes]

Thank you.

All of the information inside the brackets is taken from the infected computer. The worm is attached to the email message, and if the email message is viewed on an unpatched system, the worm will run automatically.

For further information about this exploit, please see the Microsoft Security Bulletin.

Recommendations

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.

Writeup By: Neal Hindocha

Discovered: November 04, 2002
Updated: February 13, 2007 11:41:07 AM
Also Known As: PE_BRID.A [Trend], W32/Braid.a@mm [McAfee], W32/Braid-A [Sophos], Win32.Braid.A [CA], I-Worm.Bridex.a [KAV], W32/Bride [Panda], W32/Bridex.A@mm [F-Prot]
Type: Worm
Systems Affected: Windows
CVE References: CVE-2001-0154


NOTES:

  • These instructions are for all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.
  • Whether you remove this threat manually or by using the removal tool, on Windows 98/Me computers, it is likely that the worm has overwritten the Windows file Msconfig.exe. Although this file is not necessary for Windows to function, it is a useful tool, and should be replaced from a clean backup or reinstalled.

Removal using the removal tool
Symantec Security Response has provided a free tool to remove infections of W32.Brid.A@mm, W32.Funlove.4099, and W32.Funlove.int. This is the easiest way to do this. For complete instructions on how to obtain and use the W32.Brid.A@mm/W32.Funlove.4099 Removal Tool , click here .


Manual removal

NOTE: Do this in the order shown. On Windows 95/98/Me computers, if you run (the legitimate Windows file) Regedit.exe (step 4) before you remove the copy that the worm placed in the%system% folder, it will run the copy that the worm created.
  1. Update the virus definitions.
  2. Restart the computer in Safe mode.
  3. Run a full system scan, and repair all files that are detected as W32.Funlove.4099. Delete all files detected as W32.Brid.A@mm or W32.Funlove.int.
  4. Delete the value

    regedit

    that the worm added to the registry key

    HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
For details on how to do this, read the following instructions.

To update the virus definitions:
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 once 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 repair the infected files:
  1. Start your Symantec antivirus software and make sure that it is configured to scan all files.
  2. Run a full system scan.
  3. If any files are detected as infected with W32.Funlove.4099, click Repair.
  4. If any files are detected as infected with W32.Funlove.int or W32.Brid.A@mm, click Delete.

To remove the value that the worm added to 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 the key

    HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
  4. In the right pane, delete the value

    regedit
  5. Exit the Registry Editor.


Writeup By: Neal Hindocha