Symantec Security Response
http://securityresponse.symantec.com
VBS.Neiber.A@mm
Discovered on: August 7, 2002
Last Updated on: August 8, 2002 11:30:14 AM PDT
VBS.Neiber.A@mm is a mass-mailing worm that sends itself to all addresses in the Microsoft Outlook Address Book.
The subject of the email is: Attention virus
There is no attachment. The worm is contained within the HTML body of the email message.
The worm overwrites all .vbs, and .vbe files with itself and attempts to crash the computer by continuously opening instances of Notepad.
Also Known As: VBA_NEIBER.A [Trend]
Type: Worm
Infection Length: 5,652 bytes
Systems Affected: Windows 95, Windows 98, Windows NT, Windows 2000, Windows XP, Windows Me
Systems Not Affected: Macintosh, Unix, Linux
Virus Definitions (Intelligent Updater) *
August 8, 2002
Virus Definitions (LiveUpdate?) **
August 14, 2002
*
Intelligent Updater virus definitions are released daily, but require manual download and installation.
Click here to download manually.
**
LiveUpdate virus definitions are usually released every Wednesday.
Click here for instructions on using LiveUpdate.
Wild
Number of infections: 0 - 49
Number of sites: 0 - 2
Geographical distribution: Low
Threat containment: Easy
Removal: Easy
Threat Metrics
Wild:
Low
Damage:
Medium
Distribution:
High
Damage
Payload:
Large scale e-mailing: Sends a viral email message to all address in the Microsoft Outlook Address Book
Modifies files: Overwrites all files that have the .vbs and .vbe extensions with the worm
Degrades performance: Opens an large number of occurances of Notepad.
Distribution
Subject of email: Attention Virus
Name of attachment: No attachment; the worm inserts itself into the HTML Body of the viral email message
Target of infection: Overwrites .vbs and .vbe files.
When an email containing VBS.Neiber.A@mm is received, the viral HTML body creates and executes the file %windir%\Bernie.vbs. This file contains the worm.
NOTE: %windir% is a variable. The worm locates the Windows main installation folder (by default this is C:\Windows or C:\Winnt) and copies itself to that location.
Upon execution of Bernie.vbs, VBS.Neiber.A@mm does the following:
It copy itself to %system%\Bernie.vbs,
so that it runs when you start Windows. It adds the value
Bernie wscript.exe %system%\Bernie.vbs
NOTE: %system% is a variable. The worm locates the System folder. By default this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP), and copies itself to that location.
to the registry key
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Curr entVersion\Run
Next, it checks if the value mailed equals 1 under the registry key
HKEY_CURRENT_USER\software\Bernie
If this value is not 1 then it send itself to all addresses in the Microsoft Outlook Address Book. Each address will be added to the BCC field of the email message. The email message has the following characteristics:
Subject: Attention virus
Message Body: The message body appears to be blank, but it contains the HTML source of the worm.
Attachment: There is no attachment. The worm is contained within the HTML body of the email message.
After sending the email, the worm searches local and mapped drives for files that have .vbs or .vbe extensions, and overwrite these files with the worm itself.
Finally, the worm open numerous copies of Notepad until the computer crashes.
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.
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.
NOTE: These instructions are for all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.
1. Update the virus definitions, run a full system scan, and delete all files that are detected as VBS.Neiber.A@mm.
2. Delete the value
Bernie wscript.exe %system%\Bernie.vbs
from the registry key
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Curr entVersion\Run
For details on how to do this, read the following instructions.
To scan for and delete the infected files:
1. Obtain the most recent virus definitions. There are two ways to do this:
Run LiveUpdate, which is the easiest way to obtain virus definitions. These virus definitions have undergone full quality assurance testing by Symantec Security Response and 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 have undergone full quality assurance testing by Symantec Security Response. They 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.
2. Start your Symantec antivirus program, and ensure 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.
3. Run a full system scan.
4. If any files are detected as infected by VBS.Neiber.A@mm, click Delete.
To remove 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 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_MACHINE\SOFTWARE\Microsoft\Windows\Curr entVersion\Run
4. In the right pane, delete the value
Bernie wscript.exe %system%\Bernie.vbs
5. Exit the Registry Editor.
Write-up by: Douglas Knowles
Linear Mode
