Zafi.A

Threat description

Details

CATEGORYMalware
TYPEEmail-Worm

Summary

Zafi is a mass-mailing worm that sends infected emails with Hungarian text and an attachment disguised as a link.The worm sends emails only to addresses that end with .hu so it is not likely to spread outside Hungary.Zafi was programmed to be active only in April and will cease to work starting from the 1st of May.

Removal

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

System Infection

When first run, Zafi copies itself to the Windows System Directory with a random name. The copy is then added to the registry with a random name under

HKLMSoftware\Microsoft\Windows\CurrentVersion\Run

To disguise its presence the worm opens a random link from the user's browser history. This tries to make the user believe that an actual link was opened from the infected email.

Another copy of the worm is created with a random name and '.DLL' extension.

The list of addresses the worm collects is written to several other '.DLL' files in the System Directory.

Email Propagation

Zafi collects email addresses by scanning through files with the following extensions:

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

The worms sends infected messages to all addresses that end with '.hu'.

The infected emails have the following structure:

From: [infected@sender] or [kepeslapok@meglep.hu] 
To: [targeted@user] 
Subject: kepeslap erkezett!

Tisztelt felhaszn¡lo!

annek kepeslapja erkezett!

A kepeslap feladoja: Erzsi

A lapot az alibbi cimen tudja megtekinteni:
http//matav.hu/viewcard/index=p4uo5683535GSb0123fhhf578840f0623cv2
vagy a mellekelt internetlink kattintisival.
 
 Ã…€œdv¶zlettel: Matav e-card!

 http//www.netezz.matav.hu/
 

The attachment is named to 'link.matav.hu.viewcard.index42ADR4502HHJeTYWYJDF334GSDEv25546.com'.

Payload

On 1st of May Zafi displays a political message and exits.

The other payload is a routine that terminates processes of different security applications and system tools:

zonalarm.exe
vbsntw.exe
vbcons.exe
pccguide.exe
outpost.exe
regedit.exe
regedit32.exe
navapw32.exe
pcciomon.exe
navdx.exe
navstub.exe
navw32.exe
nc2000.exe
ndd32.exe
netmon.exe
netarmor.exe
netinfo.exe
nmain.exe
nprotect.exe
ntvdm.exe
ostronet.exe
vsmain.exe
vsmon.exe
vsstat.exe
vbust.exe
mcagent.exe
fsav32.exe
fssm32.exe
fsm32.exe
fsbwsys.exe
fsgk32.exe
dfw.exe
tnbutil.exe
taskmgr.exe
winlogon.exe
fvprotect.exe
 

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