Email-Worm.VBS.LoveLetter

Detect Date 08/18/2000
Class Email-Worm
Platform VBS
Description

Technical Details

This is the Internet worm that caused the global epidemic at the beginning of May 2000. The worm spreads via e-mail by sending infected messages from
affected computers. While spreading, the worm uses MS Outlook and sends itself to all addresses that are stored in the MS Outlook Address Book. As a result, an infected computer sends as many messages to as many addresses that are kept in the MS Outlook contacts list.

The worm is written in the scripting language “Visual Basic Script” (VBS). It operates only on computers on which the Windows Scripting Host (WSH) has been installed. In Windows 98 and Windows 2000, WHS is installed by default. To
spread itself, the worm accesses MS Outlook and uses its functions and address lists, which is available in Outlook 98/2000 only, so the worm is
able to spread only in case one of these MS Oulook versions is installed.

When run, the worm sends its copies by e-mail, installs itself into the system, performs destructive actions, downloads and installs a Trojan program. The worm also has the ability to spread through the mIRC channels.

The worm contains “copyright” strings:

barok -loveletter(vbe) < i hate go to school >
by: spyder / ispyder@mail.com / @GRAMMERSoft Group / Manila,Philippines

Spreading

The worm arrives to a computer as an e-mail message with an attached VBS file that is the worm itself. The message in the original worm version has:

 The Subject:          ILOVEYOU
Message body: kindly check the attached LOVELETTER coming from me.
Attached file name: LOVE-LETTER-FOR-YOU.TXT.vbs

Upon activation by a user, (by double clicking on an attached file) the worm opens MS Outlook, gains access to the Address Book, gets all addresses from there
and sends messages with its attached copy to all of them. The message subject, body and attached file name are the same as above.

The worm also installs itself into the system. It creates its copies in the Windows directories with the names:

 in Windows directory:         WIN32DLL.VBS
 
 in Windows system directory:  MSKERNEL32.VBS, LOVE-LETTER-FOR-YOU.TXT.VBS

These files are then registered in the Windows auto-run section in the system registry:

HKLMSoftwareMicrosoftWindowsCurrentVersionRunMSKernel32 = MSKERNEL32.VBS

HKLMSoftwareMicrosoftWindowsCurrentVersionRunServicesWin32DLL = Win32DLL.VBS

As a result, the worm is re-activated each time Windows boots up.

The worm also creates a HTM dropper in the Windows system directory to use it while spreading to mIRC channels (see below). This copy has the following name:

LOVE-LETTER-FOR-YOU.TXT.HTM

Downloading a Trojan file

To install the Trojan program to the system, the worm modifies the URL to the Internet Explorer start page. The new URL points to a Web site (randonly selected from four variants) and forces Explorer to download an EXE file
from there. That file has the WIN-BUGSFIX.EXE name and is the Trojan program. The worm then registers this file in the system registry in an auto-run section:

HKLMSoftwareMicrosoftWindowsCurrentVersionRunWIN-BUGSFIX = WIN-BUGSFIX.exe

Upon the next run, Internet Exlorer downloads the Trojan and stores it in the Download directory in the system. Upon the next Windows startup, the Trojan gets control, and
copies itself to the Windows system directory with WINFAT32.EXE name.

When the Trojan has been installed into the system, the worm sets the Internet Explorer start page to blank (“about:blank”).

The downloaded and installed file is a password-stealing Trojan. It obtains the local machine name and IP address, network login(s) and password(s), RAS
information, etc., and sends them to the Trojan host. The samples that have been analyzed send messages to “mailme@super.net.ph”, the message subject looks
like what follows:

Barok… email.passwords.sender.trojan

Spreading to IRC channels

The worm scans local drives and looks for files:

MIRC32.EXE, MLINK32.EXE, MIRC.INI, SCRIPT.INI, MIRC.HLP

In case at least one of these files is found in a subdirectory, the worm
drops a new SCRIPT.INI file to there. That file contains mIRC instructions
that send a worm copy (the LOVE-LETTER-FOR-YOU.TXT.HTM file) to all users
that join to the infected IRC channel.

The SCRIPT.INI file contains the comments:

mIRC Script
Please dont edit this script… mIRC will corrupt, if mIRC will
corrupt… WINDOWS will affect and will not run correctly. thanks

Khaled Mardam-Bey
http://www.mirc.com

When an IRC user receieves that infected HTML, it is copied to an IRC download directory. The worm then is activated from that file only in case the user clicks it on. Because the browser’s security settings don’t allow scripts to access disk files and display a warning message, the worm uses a trick to avoid that. First, it displays a message to fool the user:

This HTML file need ActiveX Control
To Enable to read this HTML file
– Please press ‘YES’ button to Enable ActiveX

In case the user really clicks ‘YES’ the worm gets access to disk files and
installs itself into the system. It drops its VBS code to the Windows system directory with the MSKERNEL32.VBS name and registers it in the Windows auto-run section in system registry:

HKLMSoftwareMicrosoftWindowsCurrentVersionRunMSKernel32 = MSKERNEL32.VBS

In case ‘NO’ is chosen, the worm intercepts the mouse movement and keypress events and
reloads itself then. As a result, a user receives a warning message in an endless loop until it presses ‘YES’.

Destructive action

The worm scans the subdirectory trees on all available local and mapped drives, lists all files there and depending on the filename extension, performs actions:

  • VBS, VBE: the worm overwrites these files with its VBS body. As a result, all VBS and VBE programs in the system are overwritten with worm code.
  • JS, JSE, CSS, WSH, SCT, HTA: the worm creates a new file with an original filename plus “.VBS” extention and deletes original file; i.e., the worm
    overwrites these files with its code and renames them with VBS extension.
    For example, “TEST.JS” becowes “TEST.VBS”.
  • JPG, JPEG: the worm does the same as above, but adds a “.VBS” extension to the full file name (does not rename to “.VBS”). For example, “PIC1.JPG” becomes
    “PIC1.JPG.VBS”.
  • MP2, MP3: the worm creates a new file with a “.VBS” extension (for “SONG.MP2”, the worm creates the “SONG.MP2.VBS” file), writes its code to there and
    sets the file attribute “hidden” for the original file.

Other variants

The worm itself is a text script program, and it is spread in text source form. The worm’s code may be easily modified by hackers, and as a result, there are many variants of the original worm. Most of them are just minor
remakes and differ to the original worm just in details – there are message-fields text changed, different file names, different set of affected disk files extensions (for example, .BAT and .INI).

The Subject, message body and attached file name in different variants appear as listed below (the first block belongs to original worm version):

 Subject/body/attach name

 ILOVEYOU
   kindly check the attached LOVELETTER coming from me.
 LOVE-LETTER-FOR-YOU.TXT.vbs

 Mothers Day Order Confirmation
   We have proceeded to charge your credit card for the amount of $326.92
   for the mothers day  diamond special. We have attached a detailed
   invoice to this email. Please print out the attachment and keep it in a
   safe place.Thanks Again and Have a Happy Mothers Day!
   mothersday@subdimension.com
 mothersday.vbs

 fwd: Joke
     - no message body in message
 Very Funny.vbs

 Susitikim shi vakara kavos puodukui...
   kindly check the attached LOVELETTER coming from me.
 LOVE-LETTER-FOR-YOU.TXT.vbs

 Important ! Read carefully !!
   Check the attached IMPORTANT coming from me !
 IMPORTANT.TXT.vbs

 Dangerous Virus Warning
   There is a dangerous virus circulating.
   Please click attached picture to view it and learn to avoid it.
 virus_warning.jpg.vbs

 How to protect yourself from the IL0VEY0U bug!
   Here's the easy way to fix the love virus.
 Virus-Protection-Instructions.vbs

 Thank You For Flying With Arab Airlines
   Please check if the bill is correct, by opening the attached file.
 ArabAir.TXT.vbs

 Bewerbung Kreolina
   Sehr geehrte Damen und Herren!
 BEWERBUNG.TXT.vbs

 LOOK!
   hehe...check this out.
 LOOK.vbs

 Variant Test
   This is a variant to the vbs virus.
 IMPORTANT.TXT.vbs

 Yeah, Yeah another time to DEATH...
   This is the Killer for VBS.LOVE-LETTER.WORM.
 Vir-Killer.vbs

 I Cant Believe This!!!
   I Cant Believe I Have Just Recieved This Hate Email .. Take A Look!
 KillEmAll.TXT.vbs

 New Variation on LOVEBUG Update Anti-Virus!!
   There is now a newer variant of love bug. It was released at
   8:37 PM Saturday Night. Please Download the fo llowing patch.
   We are trying to isolate the virus. Thanks Symantec.
 antivirusupdate.vbs

 IMPORTANT: Official virus and bug fix
   This is an official virus and bug fix. I got it from our system admin.
   It may take a short while to update your system files after you run the
   attachment.
 Bug and virus fix.vbs

 Recent Virus Attacks-Fix
   Attached is a copy of a script that will reverse the effect of
   the LOVE-LETTER-TO-YOU.TXT.vbs as well as the FW:JOKE,
   Mother's Day and Lituanian Siblings.
 BAND-AID.DOC.vbs

 PresenteUOL
   O UOL tem um grande presente para voce, e eh exclusivo.
   Veja o arquivo em anexo.
   http://www.uol.com.br
 UOL.TXT.vbs

 BUG & VIRUS FIX
   I got this from our system admin. Run this to help pervent a ny recent or
   future bug & virus attack's. It may take a small while up update your files.
 MAJOR BUG & VIRUS FIX.vbs
FREE SEXSITE PASSWORDS
   cHECK IT OUT ; FREE SEX SITE PASSWORDS.
 FREE SEXSITE PASSWORDS.HTML.vbs

 You May Win $1,000,000! 1 Click Away
   kindly check the attached WIN coming from me.
 WIN.vbs

 Virus Warnings !!!
   VERY IMPORTANT PLEASE READ THIS TEXT.         TEXT ATTACHMENT.
 very-important-txt.vbs

 HOW TO BEAT VIRUSES
   kindly check the attached VIRUS INFORMATION coming from me.
   This is how you can be immune to any virus. It really helps alot!
 HOW_TO_BEAT_VIRUSES.TXT.vbs

You must read this!
   Have you read this text? You must do it!!
 C:NOTES.TXT.exe

New virus discovered!
   A new virus has been discovered! It's name is @-@Alha and Omega@-@.
   Full list of virus abilities is included in attached file @-@info.txt@-@.
   For the last information go to McAfee's web page
   Please forward this mesage to everyone you care about.
 info.txt.vbs

 Wish you were Here!
   Wish you were Here! Im having a great time!
 Wish you were Here!.postcard.vbs