Threat description


Category: Malware
Type: Virus
Platform: W32


A new variant of the Yaha virus family was found on Tuesday the 31st of December, 2002. This version, also known as Yerh, is a massmailer - like the others.


Automatic action

Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.

More scanning & removal options

More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.

You may also refer to the Knowledge Base on the F-Secure Community site for further assistance.

Eliminating a Local Network Outbreak

If the infection is in a local network, please follow the instructions on this webpage:

Technical Details

The naming of the variants in the Yaha family is a total mess. There seems to be no consensus for the variant letters and various anti-virus companies are coming up with new naming conventions and random new names for this virus. Sorry for that.

To block the virus, strip attachments ending with .SCR and .EXE and .COM at your firewall.

Technical Description

The new Yaha.M worm is very close to Yaha.K worm variant. It looks like the Yaha.K variant was a test-drive version of the worm and then its creators released a tested version with very minor modifications, that was classified as Yaha.M.

The new variant is packed with UPX file compressor. The packed file size is a bit over 34 kilobytes, the unpacked file size is over 77 kilobytes.

When run, the worm installs itself to system by copying its file to Windows System directory 3 times with the following names:

  • tcpsvs32.exe
  • nav32_loader.exe
  • WinServices.exe

Then the worm creates a startup key for WinServices.exe file in System Registry:

  • [HKLM\Software\Microsoft\Windows\CurrentVersion\Run] "WinServices" = "%WinSysDir%\WinServices.exe"
  • [HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices "WinServices" = "%WinSysDir%\WinServices.exe"

The %WinSysDir% represents Windows System directory name. Also the worm modifies the default EXE file startup key:

  • [HKCR\exefile\shell\open\command] @ = "%WinSysDir%\nav32_loader.exe "%1"%*"

The worm creates several threads that refresh its Registry keys and continuously restore worm's files if they are deleted from a hard drive. One of the threads kills processes with the following names:

  • CFINET32
  • LOCKDOWN2000
  • AVP32
  • VSHWIN32
  • NAVAPW32
  • NAVW32
  • NSCHED32
  • SCAN32
  • TDS2-98
  • TDS2-NT
  • RESCUE32
  • NAVLU32
  • PVIEW95
  • F-PROT95
  • PCCWIN98
  • IOMON98
  • FP-WIN
  • NVC95
  • _AVP32
  • _AVPCC
  • NOD32
  • NRESQ32
  • NSCHED32
  • NAVAPW32
  • NAVLU32
  • NAVW32
  • _AVPM
  • N32SCANW
  • VET95
  • SWEEP95
  • VSHWIN32
  • PCCWIN98
  • F-AGNT95
  • ACKWIN32

The worm looks for e-mail addresses in Windows Address Book, cache folders of NET and MSN messengers and in Yahoo Messenger profile folders.

Then the worm sends itself to all found e-mail addresses. The worm composes several different types of e-mails. In those messages subjects, bodies and attachment names are correlated.

A subject of an infected e-mail can be one of the following:

  • Sample Screensavers
  • Project
  • Free Screensavers 4 U
  • Patch for Klez.H
  • Patch for Klez.H
  • Patch for Elkern.gen
  • Lovers Corner
  • Things to note
  • Wanna be friends ?
  • Freak Out
  • WWE Screensavers
  • Free Screensavers
  • Free XXX
  • Free Screenavers of Love
  • Who is your Valentine
  • Are you beautiful
  • Need money ??
  • Wanna be friends ??
  • Wanna be friends ??
  • Free Demo Game
  • Demo KOF 2002
  • Play KOF 2002 4 Free
  • Wanna Rumble ??
  • Wanna Brawl ??
  • The King of KOF
  • Sample KOF 2002
  • Wanna be friends ??
  • Wanna Hack ??
  • Feel the fragrance of Love
  • Free Screensavers
  • Free rAVs Screensavers
  • XXX Screensavers
  • Jenna 4 U
  • Screensavers from Club Jenna
  • Wanna be my sweetheart ??
  • Whats up
  • World Tour
  • One Hacker's Love
  • One Virus Writer's Story
  • Visit us
  • Wanna be a HE-MAN
  • We want peace
  • Free Screensavers 4 U
  • XXX Screensavers 4 U
  • Hardcore Screensavers 4 U
  • Sample Playboy
  • Check it out
  • Check it out
  • Check it out
  • Sexy Screensavers 4 U
  • Are you a Soccer Fan ?
  • Wanna be like a stone ?
  • I Love You..
  • Learn SQL 4 Free
  • Free Win32 API source
  • Are you the BEST

An infected attachment name can be one of the following:

  • Love.scr
  • Project.exe
  • Romantic.scr
  • FixKlez.com
  • FixKlez.com
  • FixElkern.com
  • Cupid.scr
  • Notes.exe
  • MyPic.scr
  • FreakOut.exe
  • THEROCK.scr
  • Britney_Sample.scr
  • zXXX_BROWSER.exe
  • Love.scr
  • Valentines_Day.scr
  • Beautifull.scr"
  • Ways_To_Earn_Money.exe
  • MyProfile.scr
  • My_Sexy_Pic.scr
  • KOF.exe
  • King_of_Figthers.exe
  • KOF2002.exe
  • KOF_The_Game.exe
  • KOF_Demo.exe
  • KOF_Sample.exe
  • KOF_Fighting.exe
  • MyPic.scr
  • Hacker.scr
  • Romeo_Juliet.scr
  • Free_Love_Screensavers.scr
  • Ravs.scr
  • zDenka.scr
  • Jenna_Jemson.scr
  • Sexy_Jenna.scr
  • Sweetheart.scr
  • up_life.scr
  • World_Tour.scr
  • Hacker_The_LoveStory.scr
  • VXer_The_LoveStory.scr
  • Services.scr
  • Body_Building.scr
  • Peace.scr
  • Screensavers.scr
  • xxx4Free.scr
  • Hardcore4Free.scr
  • Playboy.scr
  • Plus2.scr
  • Plus6.scr
  • Real.scr
  • Sex.scrSoccer.scr
  • Stone.scr
  • I_Love_You.scr
  • SQL_4_Free.scr
  • Codeproject.scr
  • The_Best.scr

An infected message body can contain one of the following:

Hello,   The attached product is send as a part of our official campaign   for the popularity of our product.   You have been chosen to try a free fully functional sample of our   product.If you are satified then you can send it to your friends.   All you have to do is to install the software and register an account   with us using the links provided in the software. Then send this software   to your friends using your account ID and for each person who registers   with us through your account, we will pay you $1.5.Once your account reaches   the limit of $50, your payment will be send to your registration address by   check or draft.   Please note that the registration process is completely free which means   by participating in this program you will only gain without loosing anything.   Best Regards,   Admin    or     Klez.H is the most common world-wide spreading worm.It's very   dangerous by corrupting your files. Because of its very smart   stealth and anti-anti-virus technic,most common AV software   can't detect or clean it.   We developed this free immunity tool to defeat the malicious virus.   You only need to run this tool once,and then Klez will never   come into your PC    or     Hello,   Looking for some Hardcore mind boggling action ?   Install the attached browser software and browse   across millions of paid hardcore sex sites for free.   Using the software you can safely and easily browse   across most of the hardcore XXX paid sites across the   internet for free. Using it you can also clean all   traces of your web browsing from your computer.   Note:The attached browser software is made exclusivley   for demo only. You can use the software for a limited   time of 35 days after which you have to register it   at our official website for its furthur use.   Regards,   Admin.  or     Hello,   I just came across your email ID while searching in the Yahoo profiles.   Actually I want a true friend 4 life with whom I can share my everything.   So if you are interested in being my friend 4 life then mail me.   If you wanna know about me, attached is my profile along with some of my   pics. You can check and if you like it then do mail me.   I will be waiting for your mail.   Best Wishes   Your Friend..  or     <<<<<>>>>><<<<<>>>>><<<<<>>>>><<<<<>>>>><<<<<>>>>><<<<<>>>>>     This E-Mail is never sent unsolicited. If you receive this   E-Mail then it is because you have subscribed to the official   newsletter at the KOF ONLINE website.   King Of Fighters is one of the greatest action game ever made.   Now after the mind boggling sucess of KOF 2001 SNK proudly   presents to you KOF 2002 with 4 new charecters.   Even though we need no publicity for our product but this   time we have decided to give away a fully functional trial   version of KOF 2002. So check out the attached trial version   of KOF 2002 and register at our official website to get a free   copy of KOF2002 original version     Best Regards,   Admin,KOF ONLINE..   ><<<<<>>>>><<<<<>>>>><<<<<>>>>><<<<<>>>>><<<<<>>>>><<<<<>>>>>    

Also the worm can compose e-mails with the following subjects:

  • Hi
  • Hello
  • Check this shit
  • hey check it yaar
  • Who is ur Best Friend
  • make ur friend happy
  • True Love
  • Looking for Friendship
  • Let's Dance and forget pains
  • love speaks from the heart
  • Say 'I Like You' To ur friend
  • Need a friend?
  • war Againest Loneliness
  • How sweet this Screen saver
  • love speaks from the heart"
  • Shake it baby
  • The world of Friendship
  • Check ur friends Circle
  • Wowwwwwwwwwww check it
  • Are you looking for Love
  • Learn How To Love
  • Find a good friend
  • to ur friends
  • to ur lovers
  • U realy Want this
  • The Hotmail Hack
  • You are so sweet
  • I Love You
  • One Hacker's Love
  • I am in Love
  • Are you in Love

The composed e-mails can have worm's attachments with one of the following names:

  • funny.scr
  • friendship_funny.scr
  • colour_of_life.scr
  • life.scr
  • Best_Friend.scr
  • Friend_Happy.scr
  • True_Love.scr
  • GC_Messenger.exe
  • dance.scr"
  • I_Like_You.scr
  • Friend_Finder.exe
  • Be_Happy.scr
  • Sweet.scr
  • Love.scr
  • shake.scr
  • world_of_friendship.scr
  • friendship.scr
  • love.scr
  • hotmail_hack.exe

The composed e-mail body can be one of the following:

hey   did u always dreamnt of hacking ur friends hotmail account..   finally i got a hotmail hack from the internet that really works..   ur my best friend thats why sending to u..   check it..just run it..enter victim's address and u will get the pass.  or     hi,   check the attached love screensaver   and feel the fragrance of true love..  or     Hi,   check the attached screensaver..   its really wonderfool..   i got it from freescreensavers.com    or     Hi,   check ur friends circle using the attached friendship screensaver..   check the attached screensaver   and if u like it send it to all those you consider   to be true friends... if it comes back to you then   you will know that you have a circle of friends..  or     Hi,   check the attached screensaver   and enjoy the world of friendship..  or     Hi,   are u in a rocking mood...   check the attached scrennsaver and start shaking..  or     Hi,   Check the attached screensaver..  or     Hi,   Are you lonely ??..   check the attached screensaver and   forget the pain of loneliness    or     Hi,   Looking for online pals..   check the attached friend finder software..  or     Hi,   sending you a screensaver..   check it and let me know how it is...  or     Hi,   Check the attached screensaver   and feel the fragrance of true love...  or     Hey,   I just got this wonderfull screensaver from freescreensaver.com..   Just check it out and let me know how it is..  or     Hi,   I just came across it.. check out..    =====================================================================   Are you one of those unfortunate human beings who are desperately   looking for friends.. but still not getting true friends with whom   you can share your everything..    anyway you wont feel down any more cause GC Chat Network has brought   up a global chat and online match making system using its own GC   Messenger. Attached is the fully functional free version of GC   Instant Messenger and Match Making client..   Just install, register an account with us and find thousands of online   pals all over the world..   You can also search for friends by specific country,city,region etc.    Regards Admin,   GC Global Chat Network System..  or     Hi,   So you think you are in love..   is it true love ? you may think right now that you are in   true love but it is certainly possible that it is nothing   but a mere infatuation to you..    anyway to know yourself better than you have ever known check   the attached screensaver and feel the fragrance of true love..  or     Hey pal,   you know friendship is like a business...   to get something you need to give something..   though its not that harsh as business but to   get love and care from your friends you need to give   love,care and respect to your friends.. right    check the attached screensaver and you will learn how to   make your friends happy..  or     Hi,   Its quite obvious that in our life we have numerous friends   but.. BUT Best Friend can only be ONE.. right   so can you decide who is your best friend   i guess not.. cause mostly you will find that your best friend   wont care about u like somebody else..    anyway i found one way to find who is my best friend..   check it..   just check the attached screensaver.. answer some questions   in it and also ask your best friend to answer the questions..   ..then you will know more about him..  or     Hey pal,   wanna have some fun in life...   feel like life is too boring and monotonous..   check the attached screensaver and bring colours   to your black & white life.. :)    or     Hi,   I just came across this funny screensaver..   sending it to u.. hope u like it..   check out and die laughing.. :)    

It should be noted that some messages might not be displayed correctly due to typos in the tag that the author uses to separate text lines.

The worm fakes sender's name and e-mail address by substituting it with data that is hard-coded in its body. It should be noted that many names and e-mails belong to real persons or companies.

Below is the list of senders names that the worm uses:

  • Love Inc.
  • Jericho
  • Romantic Screensavers
  • Trend Micro
  • Norton Antivirus
  • McAfee Inc.
  • Cupid
  • Jonathan
  • Susan
  • Noopman
  • The Rock
  • britneyspears.org
  • zporNstarS
  • Lovers Screensavers
  • Valentine Screensavers
  • American Beauty
  • John Vandervochich
  • Ross Anderson
  • Jasmine Stevens
  • Ralph Jones
  • Clark Steel
  • Kyo Kusanagi
  • Iori Yagami
  • Terry Bogard
  • Omega Rugal
  • KOF Online
  • Cathy Kindergarten
  • Jaucques Antonio Barkinstein
  • Romeo & Juliet
  • Screensavers of Love
  • Raveena Pusanova
  • Zdenka Podkapova
  • Jenna Jameson
  • Club Jenna
  • Veronica Anderson
  • Benting
  • Paul Owen
  • admin@hackers.com
  • admin@viruswriters.com
  • admin@hackersclub.com
  • Nicolas Schwarzeneggar
  • Keanu Stevenson
  • Nomadic Screensavers
  • XXX Screensavers
  • Hardcore Screensavers
  • Playboy Inc.
  • Plus 2
  • Plus 6
  • Real Inc.
  • Sexy Screensavers
  • Super Soccer
  • Rocking Stone
  • me2K
  • SQL Library
  • Codeproject
  • Klein Anderson

And that is the list of e-mail addresses that the worm uses to fake the sender's e-mail address in an infected message:

  • loverscreensavers@love.com
  • caijob@online.sh.cn
  • romanticscreensavers@love.com
  • av_patch@trendmicro.com
  • av_patch@norton.com
  • av_patch@mcafee.com
  • cupid@freescreensavers.com
  • yjworks@online.sh.cn
  • samsun@online.sh.cn
  • ericpan@online.com.pk
  • therock@wwe.com
  • newsletters@britneyspears.org
  • admin@zpornstars.com
  • screensavers@lovers.com
  • valentinescreensavers@t2k.com
  • luoairong@21cn.com
  • hamada@seikosangyo.com
  • lubing@7135.com
  • zhouyuye@citiz.net
  • admin@kofonline.com
  • admin@kofonline.com
  • admin@kofonline.com
  • admin@kofonline.com
  • admin@kofonline.com
  • admin@kofonline.com
  • admin@kofonline.com
  • cathy@21cn.com
  • super@21cn.com
  • DNA_seraph@163.com
  • love@lovescreensavers.com
  • ravs@go2pussy.com
  • zdenka@zpornstars.com
  • jenna@jennajameson.com
  • admin@clubjenna.com
  • services@tcsonline.com
  • btq@263.com
  • paul@kqscore.com
  • admin@hackers.com
  • admin@viruswriters.com
  • admin@hackersclub.com
  • nics@nomadic.com
  • kkn@k2k.comscreensavers@nomadic.com
  • free@xxxscreensavers.com
  • free@hardcorescreensavers.com
  • sales@playboy.com
  • plus@real.com
  • plus@real.com
  • sales@real.com
  • free@sexyscreensavers.com
  • marketing@suppersoccer.com
  • stone@esterplaza.com
  • me@me2K.com
  • free@sql.library.com
  • admin@codeproject.com
  • kl@aminoprojects.com

The worm can change the default Internet Explorer startup page to point to one of these sites:

  • http://www.unixhideout.com
  • http://www.hirosh.tk
  • http://www.neworder.box.sk
  • http://www.blacksun.box.sk
  • http://www.coderz.net
  • http://www.hackers.com/html/neohaven.html
  • http://www.ankitfadia.com
  • http://www.hrvg.tk
  • http://www.hackersclub.up.to
  • http://geocities.com/snak33y3s

The worm tries to create a DoS (Denial of Service) attack on the infopak.gov.pk website.

The worm also contains an internal text message from its authors. We are not going to show it here as it uses bad language and style.

Description Created: 2006-01-01 12:59:47.0

Description Last Modified: 2006-01-01 00:00:00.0


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