W32.HLLW.Lovgate@mm

W32.HLLW.Lovgate@mm is a mass mailing worm that attempts to email itself to all the email addresses that it finds in the files, with a file extension that starts with "ht" (for example, all the .htm or .hta files). The subject and attachment of the incoming email are chosen from a predetermined list. W32.HLLW.Lovgate@mm also attempts to copy itself to all the computers on a local network, and then infect these computers. The worm also has a backdoor Trojan capability. By default, the Trojan component listens on port 10168. If the infected computer runs Windows NT, 2000, or XP, the worm will attempt to disguise itself as the normal Windows process, "LSASS.EXE." W32.HLLW.Lovgate@mm is written in the C++ programming language and is compressed with ASPack.

Also Known As:	Win32/Lovgate.A@mm [RAV], W32/Lovgate.a@M [McAfee], I-Worm.Supnot.b [KAV]
Type:	Worm
Infection Length:	77,312 bytes
Systems Affected:	Windows 95, Windows 98, Windows NT, Windows 2000, Windows XP, Windows Me
Systems Not Affected:	Windows 3.x, Macintosh, OS/2, UNIX, Linux

Virus Definitions (LiveUpdate™ Weekly) February 19, 2003 Virus Definitions (Intelligent Updater) February 19, 2003

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: Email itself to all the email addresses found in the files
  • Releases confidential info: Has backdoor capability

Distribution

• Subject of email: Various
• Name of attachment: Various
• Size of attachment: 77,312 bytes
• Ports: 10168, 20168
• Target of infection: Windows NT, 2000, XP

When W32.HLLW.Lovgate@mm is executed, it does the following:

1. Copies itself to the %System% folder as:
   • WinRpcsrv.exe
   • syshelp.exe
   • winrpc.exe
   • WinGate.exe
   • rpcsrv.exe
     
     NOTE: %System% is a variable. The worm locates the System folder and copies itself to that location. By default, this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).
     
     
2. If the infected computer runs Windows 95, 98, or ME, it adds the following line:
   
   run=rpcsrv.exe
   
   to the [windows] section in the Win.ini file.
   
3. Copies the following files to the %System% folder, and then executes them.
   • ily.dll
   • task.dll
   • reg.dll
   • 1.dll
     
     NOTE: These files are the Backdoor Trojan components of W32.HLLW.Lovgate@mm. Symantec Antivirus products will detect them as Backdoor.Trojan.
     
     
4. Adds the values:
   
   syshelp                             %system%\syshelp.exe
   WinGate initialize           %system%\WinGate.exe -remoteshell
   Module Call initialize     RUNDLL32.EXE reg.dll ondll_reg
   
   to the registry key:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
   
5. Modifies the default value of the following registry key:
   
   HKEY_CLASS_ROOT\txtfile\shell\open\command
   
   to:
   
   winrpc.exe %1
   
6. Copies itself to all the network-shared folders and subfolders as any of the following:
   
   • pics.exe
   • images.exe
   • joke.exe
   • pspgame.exe
   • news_doc.exe
   • hamster.exe
   • tamagotxi.exe
   • searchurl.exe
   • setup.exe
   • card.exe
   • billgt.exe
   • midsong.exe
   • s3msong.exe
   • docs.exe
   • humor.exe
   • fun.exe
     
     
7. Listens on port 10168 and notifies the hacker via email. The worm has a password authentication routine. After entering the correct password, the worm will start a command shell for the hacker.
   
8. Searches the following folders:
   
   • .\ (This is the folder in which the worm has been executed.)
   • winpath\
   • The folder listed in the following registry value:
     
     HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
     Explorer\Shell Folders\Personal
     
     
9. If the worm finds any files in the aforementioned folders, whose extension starts with "ht," then it will attempt to get all the email addresses from the files, create an email with an attachment infected with W32.HLLW.Lovgate@mm, and then send the infected email to the email addresses in the .ht* file.
   

1. Copies itself as %System%\ssrv.exe and creates the following registry key:
   
   HKEY_LOCAL_MACHINE\Software\KittyXP.sql\Install
   
   NOTE: %System% is a variable. The worm locates the System folder and copies itself to that location. By default, this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).
   
2. Adds the value:
   
   run              rpcsrv.exe
   
   to the registry key:
   
   HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
   
3. If the worm detects the process, "LSASS.EXE," it will attempt to create a remote thread in that particular process and inject itself into it.
   
4. Injects another thread into "LSASS.EXE", which starts a listening server that provides a command shell on port 20168 without requiring any authentication.
   
5. Starts the Backdoor Trojan component as the service, "Windows Management Extension."
   
6. Scans all the computers on the local network and uses the following passwords to log in as "Administrator:"
   • <empty.password>
   • 123
   • 321
   • 123456
   • 654321
   • guest
   • administrator
   • admin
   • 111111
   • 666666
   • 888888
   • abc
   • abcdef
   • abcdefg
   • 12345678
   • abc123
     
     NOTE: <empty.password> is a variable, which is an empty password.
     
     
7. If the worm successfully logs on to a remote computer, it will attempt to copy itself as:
   
   \\<remote.computer.name>\admin$\system32\stg.exe
   
   and then attempt to start the file on the remote computer as the service, "Microsoft NetWork Services FireWall."
   
   NOTE: <remote.computer.name> is a variable, which refers to the name of the remote computer.

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 using the W32.HLLW.Lovgate Removal Tool
This is the easiest way to remove this threat. Symantec Security Response has created a W32.HLLW.Lovgate Removal Tool.

Manual Removal
As an alternative to using the removal tool, you can manually remove this threat.

These instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Reverse the changes that the worm made to the registry.
2. Remove the text from the Windows 95, 98, Me Win.ini file (Windows 95, 98, ME only)
   Restart the computer.
3. Update the virus definitions.
4. Run a full system scan and delete all the files detected as W32.HLLW.Lovgate@mm or Backdoor.Trojan.

1. Click Start, and then click Run. (The Run dialog box appears.)
2. Type regedit
   
   Then click OK. (The Registry Editor opens.)
   
3. Navigate to the key:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   
4. In the right pane, delete the values:
   
   syshelp
   WinGate initialize
   Module Call initialize
   
5. Navigate to the key:
   
   HKEY_CLASS_ROOT\txtfile\shell\open\command
   
6. In the right pane, modify the default value to:
   
   notepad.exe %1
   
7. Navigate to the key:
   
   HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
   
8. In the right pane, delete the value: run
   
9. Delete the key:
   
   HKEY_LOCAL_MACHINE\Software\KittyXP.sql
   
10. Exit the Registry Editor.

1. Click Start, and then click Run.
2. Type the following:
   
   edit c:\windows\win.ini
   
   And then click OK. (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 an entry similar to:
   
   run=rpcsrv.exe
   
4. If this line exists, highlight the text. Be sure that you do not select any other text, and then press Delete.
   
5. Click File, and then click Save.
   
6. Click File, and then click Exit.

• 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 here. For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, click here.

1. 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."
2. Run a full system scan.
3. If any files are detected as infected with W32.HLLW.Lovgate@mm or Backdoor.Trojan, click Delete.

Revision History:

January 24, 2003: Added link to the W32.HLLW.Lovgate Removal Tool.

Write-up by: Robert X Wang and Peter Ferrie