Summary

Zafi.C is a variant of the Zafi mass-mailing worm family. This worm sends email messages with infected attachments in several different languages.

The payload of Zafi.C is a Distributed Denial-of-Service attack against google.com, microsoft.com and www.miniszterelnok.hu.

Additional Details

System Infection

When the worm's file is run, it copies itself as 'svchost.com' to Windows System folder and creates a startup key for this file in the Registry:

 [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
 "_svchost.con" = "%SystemDir%\svchost.com"

%SystemDir% represents the Windows System folder name, for example C:\Windows\System32 on Windows XP systems.

Another copy is created in the same directory as 'svchost.con'.

Zafi.C keeps its state information in the registry under

 [HKEY_LOCAL_MACHINE\Software\Microsoft\UpdateZ3]

Email propagation

Zafi.C collects email addresses from Windows Address Book and different files (eg. HTM, TXT, MBX, etc). The worm composes the messages it sends based on complex rules in many different languages. The email attachments might have double extensions (composed from .DOC/.TXT and .EXE/.SCR).

Payload

The payload of Zafi.C is a Distributed Denial-of-Service attack against

 google.com
 microsoft.com
 www.miniszterelnok.hu

Detection

Detection for this malware was published on October 27th, 2004 in the following F-Secure Anti-Virus updates:

[FSAV_Database_Version]
Version=2004-10-27_03



Write-up: F-Secure Antivirus Research Team, October 27th, 2004;