Threat Description

Zafi.B

Details

Aliases: Zafi.B, W32/Zafi.B@mm, I-Worm.Zafi.b
Category: Malware
Type: Email-Worm
Platform: W32

Summary


A new variant of Zafi worm - Zafi.B is spreading. While the original Zafi.A uses only Hungarian, the new Zafi.B spreads in email in English, Italian, Spanish, Russian, Swedish etc.The worm sends itself in emails mostly as .pif attachment and in rare cases it sends .exe or .com.



Removal


Automatic Disinfection

Allow F-Secure Anti-Virus to disinfect the relevant files.

For more general information on disinfection, please see Removal Instructions.

Eliminating a Local Network Outbreak

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



Technical Details


Zafi.B spreads in FSG! packed form which is 12800 bytes in size. The body unpacks to around 30 KiB of hand-written assembly code.

System Infection

When Zafi.B is started it copies itself to the Windows System Directory with a random .DLL and random .EXE name. The .EXE file is added to the registry as

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]   "_Hazafibb" = "%SysDir%\.exe"    

Several additional files are created in the System Directory with random name and .DLL extension. The worm keeps its internal data in those.

Zafi.B enumerates all the directories in the system and copies itself as either 'winamp 7.0 full_install.exe' or 'Total Commander 7.0 full_install.exe' to the ones that contain 'share' or 'upload' in their name.

Email Propagation

Zafi.B looks into the Windows Address Book and different files and tries to gather email addresses. Files with the following extensions are checked:

htm  wab  txt  dbx  tbb  asp  php  sht  adb  mbx  eml  pmr  

Using its own SMTP engine the worm sends messages with infected attachments in many different languages.

For email addresses in the following domains the worms sends messages in the respective languages:

.hu .sp .ru .dk .ro .se .no .fi .lt .pl .pt .de .nl .cz .fr .it .mx .at   

For Hungarian recipients there are three different messages. Any recipient that is not on the list (including .COM, .NET, etc.) is sent one of the three predefined English messages.

Sender: Anita  Subject: eIngyen SMS!  Attachment: "regiszt.php?3124freesms.index777.pif"  ------------------------ hirdet©s -----------------------------  A sikeres 777sms.hu es az axelero.hu timogatisival ºjra  indul az ingyenes sms k¼ld? szolgiltatis! Jelenleg ugyan  korlitozott szimban, napi 20 ingyen smst lehet felhasznilni.  K¼ldj te is SMST! Nehiny kattintis es a mellekelt regisztricios  lap kit¶ltese utin azonnal igenybevehet?! B?vebb informiciot  a www.777sms.hu oldalon talilsz, de siess, mert az els? ezer  felhasznilo k¶z¶tt ertekes nyeremenyeket sorsolunk ki!  ------------------------ axelero.hu ---------------------------  Sender: Anita  Subject: eTessek mosolyogni!!!  Attachment: "meztelen csajok fociznak.flash.jpg.pif"  Ha ez a kep sem tud felviditani, akkor feladom!  Sok puszi:  Sender: Anita  Subject: eSoxor Csok!  Attachment: "anita.image043.jpg.pif"  Sender: Claudia  Subject: eImportante!  Attachment: "link.informacion.phpV23.text.message.pif"  Informacion importante que debes conocer, -  Sender: Katya  Subject: oKatya  Attachment: "view.link.index.image.phpV23.sexHdg21.pif"  ADAOIU   OEIE  Sender: .  Subject: eE-Kort!  Attachment: "link.ekort.index.phpV7ab4.kort.pif"  Mit hjerte banker for dig!  Sender: Marica  Subject: eEcard!  Attachment: "link.showcard.index.phpAv23.ritm.pif"  De cand te-am cunoscut inima mea are un nou ritm!  Sender: Anna  Subject: eE-vykort!  Attachment: "link.vykort.showcard.index.phpBn23.pif"  Till min Alskade...  Sender: Erica  Subject: eE-Postkort!  Attachment: "link.postkort.showcard.index.phpAe67.pif"  Vakre roser jeg sammenligner med deg...  Sender: Katarina  Subject: eE-postikorti!  Attachment: "link.postikorti.showcard.index.phpGz42.pif"  Iloista kesaa!  Sender: Magdolina  Subject: eAtviruka!  Attachment: "link.atviruka.showcard.index.phpGz42.pif"  Linksmo gimtadieno!  Sender: Beate  Subject: eE-Kartki!  Attachment: "link.kartki.showcard.index.phpVg42.pif"  W Dniu imienin...  Sender: @  Subject: eCartoe Virtuais!  Attachment: "link.cartoe.viewcard.index.phpYj39.pif"  Te amo...  Sender: Alice  Subject: eFlashcard fuer Dich!  Attachment: "link.flashcard.de.viewcard34.php.2672aB.pif"  Hallo!  hat dir eine elektronische Flashcard geschickt.  Um die Flashcard ansehen zu koennen, benutze in deinem Browser  einfach den nun folgenden link:  http://flashcard.de/interaktiv/viewcards/view.php3?card=267BSwr34  Viel Spass beim Lesen wuenscht Ihnen ihr...  Sender:  Subject: eEr staat een eCard voor u klaar!  Attachment: "postkaarten.nl.link.viewcard.index.phpG4a62.pif"  Hallo!  heeft u een eCard gestuurd via de website nederlandse  taal in het basisonderwijs...  U kunt de kaart ophalen door de volgende url aan te klikken of te  kopiren in uw browser link:  http://postkaarten.nl/viewcard.show53.index=04abD1  Met vriendelijke groet,  De redactie taalsite primair onderwijs...  Sender: Hanka  Subject: eElektronicka pohlednice!  Attachment: "link.seznam.cz.pohlednice.index.php2Avf3.pif"  Ahoj!  Elektronick pohlednice ze serveru http://www.seznam.cz  Sender: Claudine  Subject: eE-carte!  Attachment: "link.zdnet.fr.ecarte.index.php34b31.pif"  vous a envoye une E-carte partir du site zdnet.fr  Vous la trouverez, l'adresse suivante link:  http://zdnet.fr/showcard.index.php34bs42  www.zdnet.fr, plus de 3500 cartes virtuelles, vos pages web  en 5 minutes, du dialogue en direct...  Sender: Francesca  Subject: eTi e stata inviata una Cartolina Virtuale!  Attachment: "link.cartoline.it.viewcard.index.4g345a.pif"  Ciao!  ha visitato il nostro sito, cartolina.it e ha creato una  cartolina virtuale per te! Per vederla devi fare click  sul link sottostante: http://cartolina.it/asp.viewcard=index4g345a  Attenzione, la cartolina sara visibile sui nostri server per  2 giorni e poi verra rimossa automaticamente.  Sender: Jennifer  Subject: eYou`ve got 1 VoiceMessage!  Attachment: "link.voicemessage.com.listen.index.php1Ab2c.pif"  Dear Customer!  You`ve got 1 VoiceMessage from voicemessage.com website!  You can listen your Virtual VoiceMessage at the following link:  http://virt.voicemessage.com/index.listen.php2=35affv  or by clicking the attached link.  Send VoiceMessage! Try our new virtual VoiceMessage Empire!  Best regards: SNAF.Team (R).  Szia!  Aranyos vagy, jo volt dumcsizni veled a neten!  Remelem tetszem, es szeretnem ha te is k¼ldenel kepet  magadrol, addig is csok:  Sender: Jennifer  Subject: eDon`t worry, be happy!  Attachment: "www.ecard.com.funny.picture.index.nude.php356.pif"  Hi Honey!  I`m in hurry, but i still love ya...  (as you can see on the picture)  Bye - Bye:  Sender: David  Subject: eCheck this out kid!!!  Attachment: "jennifer the wild girl xxx07.jpg.pif"  Send me back bro, when you`ll be done...(if you know what i mean...)  See ya,   

In rare cases the email will have an attachment with the name 'Surprise' and extension '.com', '.exe' or '.pif'.The worm does not send emails to addresses that contain any of these strings:

win  use  info  help  admi  webm  micro  msn  hotm  suppor  syma  vir  trend  panda  yaho  cafee  sopho  google  kasper   
Payload

Zafi.B terminates any application that has the words 'firewall' or 'virus' in it. These files are overwritten with a copy of the worm.

Several Windows tools, like Task Manager, Registry Editor are disabled when the worm is active. Zafi.B opens these files with exclusive locking to prevent anything else from opening them.






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