Parent class: VirWare
Viruses and worms are malicious programs that self-replicate on computers or via computer networks without the user being aware; each subsequent copy of such malicious programs is also able to self-replicate. Malicious programs which spread via networks or infect remote machines when commanded to do so by the “owner” (e.g. Backdoors) or programs that create multiple copies that are unable to self-replicate are not part of the Viruses and Worms subclass. The main characteristic used to determine whether or not a program is classified as a separate behaviour within the Viruses and Worms subclass is how the program propagates (i.e. how the malicious program spreads copies of itself via local or network resources.) Most known worms are spread as files sent as email attachments, via a link to a web or FTP resource, via a link sent in an ICQ or IRC message, via P2P file sharing networks etc. Some worms spread as network packets; these directly penetrate the computer memory, and the worm code is then activated. Worms use the following techniques to penetrate remote computers and launch copies of themselves: social engineering (for example, an email message suggesting the user opens an attached file), exploiting network configuration errors (such as copying to a fully accessible disk), and exploiting loopholes in operating system and application security. Viruses can be divided in accordance with the method used to infect a computer:- file viruses
- boot sector viruses
- macro viruses
- script viruses
Class: Email-Worm
Email-Worms spread via email. The worm sends a copy of itself as an attachment to an email message or a link to its file on a network resource (e.g. a URL to an infected file on a compromised website or a hacker-owned website). In the first case, the worm code activates when the infected attachment is opened (launched). In the second case, the code is activated when the link to the infected file is opened. In both case, the result is the same: the worm code is activated. Email-Worms use a range of methods to send infected emails. The most common are: using a direct connection to a SMTP server using the email directory built into the worm’s code using MS Outlook services using Windows MAPI functions. Email-Worms use a number of different sources to find email addresses to which infected emails will be sent: the address book in MS Outlook a WAB address database .txt files stored on the hard drive: the worm can identify which strings in text files are email addresses emails in the inbox (some Email-Worms even “reply” to emails found in the inbox) Many Email-Worms use more than one of the sources listed above. There are also other sources of email addresses, such as address books associated with web-based email services.Read more
Platform: VBS
Visual Basic Scripting Edition (VBScript) is a scripting language interpreted by Windows Script Host. VBScript is widely used to create scripts on Microsoft Windows operating systems.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
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