Threat Description



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


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, and


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 scanning or removal options is available in the documentation for your F-Secure security product on the Downloads section of our Home - Global site.

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

Contact Support

For further assistance, F-Secure customers can request support online via the Request support or the Chat forms on our Home - Global site.

Technical Details

System Infection

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

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

%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

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).


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


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

Detection Type: PC
Database: 2004-10-27_03

Description Details: F-Secure Antivirus Research Team, October 27th, 2004


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