What are good sources for virus signature data?

Is there any website which provides antivirus definition database to help make new antiv开发者_开发技巧irus software?

ClamWin is a free, open-source antivirus software. You might find something useful there.

Have you tried looking into ClamAV? Open source AV program, can be linked to via API, and you should be able to get the database for it, but I'm not sure how offhand.

There are a few CSV files that contain a large (but not even close to commercial companies) virus signature definitions. Bellow there are in total between 2-4k definitions.

http://files.codes-sources.com/fichier_fullscreen.aspx?id=21418&f=virussignatures.txt&lang=en

and here

http://www.nlnetlabs.nl/downloads/antivirus/antivirus/virussignatures.strings

Hope it helps!