W32.HLLW.Nautic

SUMMARY

W32.HLLW.Nautic is a worm that creates and shares a folder on the network. The worm then copies itself to this folder as a file name that is designed to trick users into executing the malicious files. Some of the possible file names are as follows:

• Windows XP Crack.exe
• Warcraft III Trainer (Cheats).exe
• Norton Antivirus 2003 Installer.exe
• Bikini Girls.exe
• Halflife Patch.exe
• Funny Screensaver.exe
• Hack Hotmail Account.exe
• Age of Empires II_Keygen(Serial).exe
• Warcraft III - Crack.exe
• Winzip 8.2 (Beta 3) Full Version Installer.exe
• Playboy_Screensaver_Install.exe

The worm also listens for commands on one of the following ports:

• 335
• 2281
• 5679
• 9148

Protection

• Virus Definitions (LiveUpdate™ Weekly) September 4, 2002
• Virus Definitions (Intelligent Updater) August 30, 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: Low
• Compromises Security Settings: Allows unauthorized access to an infected computer

Distribution

• Distribution Level: Medium
• Ports: 335, 2281, 5679, 9148
• Shared Drives: Creates and shares a folder on an infected computer. Can also modify Drives D through K if a given command is passed through the network connection.

TECHNICAL DETAILS

When W32.HLLW.Nautic runs, it first checks for the presence of an installed Windows Debugger. If it finds one, it exits. If it does not find one, it does the following:

If the day is December 25, the worm displays the text:

Today is Christmas day !! Yah ?? - Santa Claus [--Nautical--]

The worm checks if the current file name is one of the following:

• NTDLL.exe
• Win32.exe
• Explore.exe
• Kernel32.exe
• krnl286.exe
• Dllhost32.exe
• MSTCP.exe
• CRSS.exe
• Winlogon32.exe
• Winsrvc.exe
• Ntoskrn.exe
• Vmm32.exe
• Sysmon.exe
• System32.exe
• Sys.exe
• Win.exe
• Rundil32.exe
• Msrvcp.exe
• Msgmsr.exe
• Mscde32.exe
• Regsvclib.exe
• Reg32.exe
• Registry32.exe
• Service.exe
• Rpcsrvc.exe

If the current file name is not one of the following, it displays the following message:



It then copies itself to the %system% folder as one of the files in the previous list.

The worm then checks whether the value

Nautical

under the registry key

HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersion

is equal to "1".

If it is not, the worm configures itself to start when Windows starts by performing one of the following actions:

• Adding the value
  
  Run %system%<file name from above list>
  
  to the registry key
  
  HKEY_CURRENT_USERSoftwareMicrosoftWindows NTCurrentVersionWindows
  
• Adding the value
  
  System32 %system%<file name from above list>
  
  to the registry key
  
  HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
  
• Adding the value
  
  WinSys %system%<file name from above list>
  
  to the registry key
  
  HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun
  
• Adding the value
  
  Msgsvc32 %system%<file name from above list>
  
  to the registry key
  
  HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
  
• Adding the line
  
  run=%system%<file name from above list>
  
  to the %windir%Win.ini file

After it has completed these actions, it sets the value

Nautical

under the registry key

HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersion

to 1.
W32.HLLW.Nautic creates and shares a folder on the network. This folder is created in the %system% folder, the %windir% folder, or the %Program Files% folder. The folder name is one of the following:

• Porn Stuff
• My Personal Stuff
• Softwarez
• Cracrs_Serials
• Private - Do Not Enter
• Mp3z
• Misc Stuff
• Fun Stuff
• Pics
• Xxx Movies
• Full Vcds
• Top Secret
• My Projects
• Funny Pictures
• Nude Pics

The worm then copies itself to this folder as a file name that is designed to trick users into executing the malicious files. The following are some of the possible file names:

• Windows XP Crack.exe
• Warcraft III Trainer (Cheats).exe
• Norton Antivirus 2003 Installer.exe
• Bikini Girls.exe
• Halflife Patch.exe
• Funny Screensaver.exe
• Hack Hotmail Account.exe
• Age of Empires II_Keygen(Serial).exe
• Warcraft III - Crack.exe
• Winzip 8.2 (Beta 3) Full Version Installer.exe
• Playboy_Screensaver_Install.exe

It configure this folder to be shared on the network by adding the following registry values

Flags
Parm1enc
Parm2enc
Path <folder path from above, for example %Program Files%NUDE PICS>
Remark
Type

to the registry key

HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionNetworkLanMan<folder path from above>

After the worm shares the folder, it sets the value

Nautica

under the registry key

HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersion

to 1.

The worm also supports certain backdoor-like functionality. It supports two different commands:

• EJECT
• UNLOAD

The EJECT function attempts to send commands to drives D through K.
The UNLOAD function closes the network connection and stops listening.

The worm listens for commands on one of the following ports:

• 335
• 2281
• 5679
• 9148

When the worm receives a connection to the port, it displays this message:



The worm propagates the command to all infected computers on a given domain by using mailslots. A mailslot is described by Microsoft as follows:

"A mailslot is a mechanism for one-way interprocess communications (IPC). Applications can store messages in a mailslot."

The worm uses this mechanism to propagate commands sent to any of the infected computers to all computers on the infected domain.

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

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 W32.HLLW.Nautic.
2. Reverse any changes that the worm made to the registry.
3. On Windows 95/98/Me-based computers, remove the line that the worm added to the Win.ini file.
   

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 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.
3. Run a full system scan.
4. If any files are detected as infected with W32.HLLW.Nautic, click Delete.

To reverse changes that the worm made 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.

NOTE: Because the worm makes different changes to the registry on different computers, you must check all locations that are described here.

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_MACHINESoftwareMicrosoftWindowsCurrentVersionNetworkLanMan<folder path to worm>
   
   Delete the key if it exists.
   
4. Navigate to the key
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindows NTCurrentVersionWindows
   
5. In the right pane, delete the value
   
   Run %System%<file name from above>
   
6. Navigate to the key
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
   
7. In the right pane, delete these values:
   
   System32 %System%<worm file name>
   Msgsvc32 %System%<file name from above>
   
8. Navigate to the key
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun
   
9. In the right pane, delete the value
   
   WinSys %System%<worm file name>
   
10. Exit the Registry Editor.

To edit the Win.ini file (Windows 95/98/Me only):

NOTE: (For Windows Me users only) Due to the file-protection process in Windows Me, a backup copy of the file that you are about to edit exists in the C:WindowsRecent folder. Symantec recommends that you delete this file before you continue with the steps in this section. To do this using Windows Explorer, go to C:WindowsRecent, and in the right pane select the Win.ini file and delete it. It will be regenerated as a copy of the file that you are about to edit when you save your changes to that file.

1. Click Start, and click Run.
2. Type the following, and then click OK.
   
   edit c:windowswin.ini
   
   The MS-DOS Editor opens.
   
   NOTE: If Windows is installed in a different location, make the appropriate path substitution.
   
3. In the [windows] section of the file, look for a line similar to the following:
   
   run=%system%<worm file name>
   
4. If it exists, select the entire line. Be sure that you do not select any other text, and then press Delete.
5. Click File, and click Save.
6. Click File, and click Exit.