May have been posted already... if so... sorry... if not...
Source: Symantec Corporation
Discovered on: April 14, 2004
W32.Netsky.V@mm is a mass-mailing worm that sends itself to email addresses it gathers from certain files on the system. This variant does not send an attachment with its email messages, but instead sends a link to the compromised computer in its attempt to download and run the worm's executable.
W32.Netsky.V@mm relies on several exploits to replicate successfully (see the Technical Details section below).
The From line of the email is spoofed, and its Subject line and message body vary. The worm is packed with UPXSh!t v0.07, UPXSh!t v0.06, and UPX 1.24.
Also Known As: W32/Netsky.v@MM
Infection Length: 19,432 bytes (including 1,000 bytes appended)
Systems Affected: Windows 2000, Windows 95, Windows 98, Windows Me, Windows NT, Windows Server 2003, Windows XP
Systems Not Affected: DOS, Linux, Macintosh, OS/2, UNIX
When W32.Netsky.V@mm is executed, it performs the following actions:
1. Copies itself using the following filenames:
Note: %Windir% is a variable. The worm locates the Windows installation folder (by default, this is C:\Windows or C:\Winnt) and copies itself to that location.
2. Creates a mutex named "_-=oOOSOkOyONOeOtOo=-_", which allows only one instance of the worm to execute.
3. Adds the value:
to the registry key:
so that the dropper component of the worm runs when you start Windows.
4. Launches a separate thread that enumerates all the disk drives and retrieves email addresses from the files with the following extensions:
5. If the system date is April 22nd, 2004 through April 28th, 2004 it will attempt to perform a Denial of Service (DoS) attack against the following sites:
6. The worm installs an HTTP server that listens on port 5557.
7. The worm installs an FTP server that listens on port 5556. The FTP connection is logged into the file c:\fvw.log.
8. W32.Netsky.V@mm uses its own SMTP client engine to send itself to the email addresses it finds.
The email has the following characteristics:
Subject: randomly selected from the following list:
Gateway Status failure
Server Status failure
Mail delivery failed
Mail Delivery Sytem failure
Body: randomly selected from the following list:
The processing of this message can take a few minutes...
Converting message. Please wait...
Please wait while loading failed message...
Please wait while converting the message...
The From: field of the message may be spoofed using the following email address:
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.
The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.
1. Disable System Restore (Windows Me/XP).
2. Update the virus definitions.
3. Restart the computer in Safe mode or VGA mode.
4. Run a full system scan and delete all the files detected as W32.Netsky.V@mm.
5. Reverse the changes made to the registry.
For details on each of these steps, read the following instructions.
1. To disable 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.
Note: When you are completely finished with the removal procedure and are satisfied that the threat has been removed, re-enable System Restore by following the instructions in the aforementioned documents.
2. To update 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. To restart the computer in Safe mode or VGA mode
Shut down the computer and turn off the power. Wait for at least 30 seconds, and then restart 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, read the document, "How to start the computer in Safe Mode."
For Windows NT 4 users, restart the computer in VGA mode.
4. To scan for and delete the infected files
a. 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."
b. Run a full system scan.
c. If any files are detected as infected with W32.Netsky.V@mm, click Delete.
5. To reverse the changes made to the registry
WARNING: Symantec strongly recommends that you back up the registry before making 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.
a. Click Start, and then click Run. (The Run dialog box appears.)
b. Type regedit
Then click OK. (The Registry Editor opens.)
c. Navigate to the key:
d. In the right pane, delete the value:
e. Exit the Registry Editor.
f. Restart the computer in Normal mode. For instructions, read the section on returning to Normal mode in the document, "How to start the computer in Safe Mode."