Email-Worm.Win32.LovGate.b

Technical Details

I-Worm.Lovgate.a (aka Supnot.a) is a worm virus spreading via the Internet as an attachment to infected emails. The worm also spreads through local area networks and has a backdoor routine. There are several worm variants known which are very similar to each other.

The worm itself is a Windows PE EXE file, written in Microsoft Visual C++, and compressed by AsPack.

The compressed file size is about 77K, decompressed size - about 164K.

The worm activates from infected email only when a user clicks on the attached file. While spreading through local area networks the worm tries to run its remote copies by using WinNT functions.

When run the worm installs itself to the system, runs its spreading and backdoor routines.

Installing

While installing the worm copies itself to the Windows system directory under several names and registers these files in the system registry auto-run key (under WinNT) and/or in the "run" command in the WIN.INI file (under Win9x).

Worm copies have the following names:

rpcsrv.exe
syshelp.exe
winrpc.exe
WinGate.exe
WinRpcsrv.exe

The registry keys are:

[HKCU\Software\Microsoft\Windows NT\CurrentVersion\Windows]
 "Run"="rpcsrv.exe"

[HKLM\Software\Microsoft\Windows\CurrentVersion\Run]
 "syshelp"="%SystemDir%\syshelp.exe"

[HKLM\Software\Microsoft\Windows\CurrentVersion\Run]
 "WinGate initialize"="%SystemDir%\WinGate.exe -remoteshell"
 "Module Call initialize"="RUNDLL32.EXE reg.dll ondll_reg"

[HKCR\txtfile\shell\open\command]
 "winrpc.exe %1"

Spreading: email

To spread in emails 'supnot' uses two different methods:

1. The worm looks for "*.HT*"-files (HTM, HTML) in the current directory, Windows directory and the "My Documents" directory (including subdirectories as well), scans them for email-like text strings and sends infected messages to addresses found. To send infected message the worm uses a direct connection to the default SMTP server, or connects to the "smtp.163.com" server.

Following are different variations of 'supnot' message attributes:

 Subject:
 Text:
 Attachment:

  Cracks!
    Check our list and mail your requests!
    CrkList.exe

  The patch
    I think all will work fine.
    Patch.exe

  Last Update
    This is the last cumulative update.
    LUPdate.exe

  Do not release
    This is the pack ;)
    Pack.exe

  Beta
    Send reply if you want to be official beta tester.
    _SetupB.exe

  Help
    I'm going crazy... please try to find the bug!
    Source.exe

  Evaluation copy
    Test it 30 days for free.
    Setup.exe

  Pr0n!
    Adult content!!! Use with parental advisory.
    Sex.exe

  Roms
    Test this ROM! IT ROCKS!.
    Roms.exe

  Documents
    Send me your comments...
    Docs.exe
  

The worm gets emails from Inboxes and "answers" them by using Windows MAPI functions. Replies look like:

 Subject:   Re: [original email subject]
 Text:

   [user name] wrote:
   ====
   > [original email text]
   ====
   [email domain name] account auto-reply:

  ' I'll try to reply as soon as possible.
  Take a look to the attachment and send me your opinion! '

        > Get your FREE [email domain name] account now! <
 

for example:

The attached file name is randomly selected from the following variants:

  pics.exe          SETUP.EXE     
  images.exe        Card.EXE      
  joke.exe          billgt.exe    
  PsPGame.exe       midsong.exe   
  news_doc.exe      s3msong.exe   
  hamster.exe       docs.exe      
  tamagotxi.exe     humor.exe     
  searchURL.exe     fun.exe       

Infecting Local Networks
The worm finds network resources (shared writeable disks and directories) and copies itself to them under randomly chosen names:

  pics.exe             SETUP.EXE
  images.exe           Card.EXE
  joke.exe             billgt.exe
  PsPGame.exe          midsong.exe
  news_doc.exe         s3msong.exe
  hamster.exe          docs.exe
  tamagotxi.exe        humor.exe
  searchURL.exe        fun.exe

If a network resource is password protected it also tries to request 'write' access using the following information:

 Login:    "guest", "Administrator"
 Password: "123", "321", "123456", "654321", "administrator", "admin",
           "111111", "666666", "888888", "abc", "abcdef", "abcdefg", "12345678", "abc123"

If the login is successful the worm creates a remote copy of itself named "stg.exe" and tries to launch it on the remote computer.

Backdoor

Supnot launches a "backdoor" routine that uses the IPC (Interprocess Communication) technique: it creates a pipe connected to a command processor that is launched on the victim computer - CMD.EXE in Windows NT/2000/XP or COMMAND.COM in Windows 9x/ME. This allows the worm's "owner" to control the victim computer remotely.

The backdoor is launched three different ways:

  My I-WORM-and-IPC-20168 running!