Classification

Category :

Malware

Type :

Worm

Aliases :

Netav, I-Worm.Netav

Summary

NetAV is the worm that spreads in email messages. email addresses are collected from the users' Address Book and HTML files located in the 'Temporary Internet Files' folder. Every Tuesday the worm searches for *.DOC files in the 'My Documents' folder and, if there are several files there, picks one randomly and sends it out. The worm does not spread on Tuesday, it only sends *.DOC files out.

Removal

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

Every Thursday the worm regenerates the new address list that stores in the ICMAIL.DLL file in the Windows System directory.

This worm sends itself with the following subject lines:

Hello
For you
Try it
Re:

and the following bodies:

Hi
Here is what you asked, bye.
Hello
Maybe you could help me with this, bye.
Hello
Now you can try it, bye.

The following names are given to the worm's attachment:

HGAME.EXE
MININET.EXE
NETAV.EXE

Subject, body and attachment name are selected randomly from the above given list.

When the worm is first started it shows a fake error message:

"This file does not work on this system"

And then it installs itself to system. It copies itself to Windows System Directory as 'NETAV.EXE' file. Then it adds the path of that file to the System Registry:

[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run\NETAV Agent]

This way the worm starts during all Windows sessions. To disinfect the worm it's enough to delete its file from Windows System folder.