W32.Ameter@m

SUMMARY

W32.Ameter@m is a worm that requires Borland C++ 6.0 runtime libraries be installed for it to run. It overwrites all .exe files (except for Emm386.exe and Setver.exe) that reside in the %windir% folder.

It also sends itself to an email address that is contained within the worm. This email message has the following characteristics:

Subject: Brigada Ocho Bitmap Tools
Attachment: <original worm file name>

Protection

• Virus Definitions (LiveUpdate™ Weekly) September 25, 2002
• Virus Definitions (Intelligent Updater) September 24, 2002

Threat Assessment

Wild

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

Damage

• Damage Level: High
• Large Scale E-mailing: Attempts to send itself to 1 email address.
• Modifies Files: Overwrites all .exe files in the Windows folder

Distribution

• Distribution Level: Low
• Subject of Email: Brigada Ocho Bitmap Tools
• Name of Attachment:
• Size of Attachment: 10,752 bytes
• Target of Infection: .exe files in the %Windows% directory

TECHNICAL DETAILS

When W32.Ameter@m runs, it does the following:

On Windows NT/2000/XP-based computers it adds the value

brigadaNT <original worm file name>

to the registry key

HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsNTCurrentVersionRunServices

On Windows 95/98/Me-based computers it adds the value

brigadaWin <original worm file name>

to the registry key

HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRunServices

Next, the worm determines whether the following registry key exists:

HKEY_LOCAL_MACHINESoftwarerigadaInstall

If it does not exist, the worm performs the following actions:

It overwrites all .exe files that reside in the %windir% folder, except for Emm386.exe and Setver.exe.

NOTE: %windir% is a variable. The worm locates the Windows installation folder (by default this is C:Windows or C:Winnt) and delete the files in that folder.

The worm then creates the registry key

HKEY_LOCAL_MACHINESoftwareEnergyInstall

If it can successfully find the functions that it needs to send email, it displays this message:



Otherwise, it displays this message:



If it finds the functions that it needs to send email, the worm then checks whether a certain name exists in the Windows Address Book.

• If the name does not exist, the worm displays a message and then deletes all files in the %windir% folder.
• If the name does exist, the worm sends the following email message to the address that is associated with the specific name:
  
  Subject: Brigada Ocho Bitmap Tools
  Message Body:
  Hy <recipient name>
  I was hacked this Tools about Brigada Ocho. This Tools can change your Login Bitmap on Windows Start this Very funny tools, and selected you questions to.
  Attachment: <original worm file name>

• If it is successful in sending the message, the worm displays this message:
  Title: Brigada Ocho Bitmap Tools
  Message: Thanks for Enjoy us
  
• If it fails to send the message, then it displays this message:
  Title: Brigada Ocho Bitmap Tools
  Message: Please Install first vb6 tools

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

NOTES:

• These instructions are for all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.
• If the worm has overwritten or deleted files that are needed by the operating system, you must first reinstall the operating system or restore the files from a clean backup.

1. Update the virus definitions
2. Run a full system scan, and delete all files that are detected as W32.Ameter@m.
3. Delete whichever of these values
   
   brigadaNT <original worm file name>
   brigadaWin <original worm file name>
   
   exists in the registry key
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   

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 one time 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 scan for and delete the infected files:

1. Start your Symantec antivirus program, and make sure that it is configured to scan all files.
   • Norton AntiVirus consumer products: Read the document How to configure Norton AntiVirus to scan all files.
   • Symantec enterprise antivirus products: Read the document How to verify 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 W32.Ameter@m, click Delete.

To delete 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_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
4. In the right pane, delete whichever of these values you find:
   
   brigadaNT <original worm file name>
   brigadaWin <original worm file name>
   
5. Exit the Registry Editor.