These techniques are becoming insufficient. Indeed, emulation based techniques can only check the program's behavior in a limited time interval. As for signature based systems, it is very easy to virus developers to get around them. Thus, a robust malware detection technique needs to check the behavior (not the syntax) of the program without executing it. We show in this talk how using behavior signatures allow to efficiently detect malwares in a completely static way. We implemented our techniques in a tool, and we applied it to detect several viruses. Our results are encouraging. In particular, our tool was able to detect more than 800 viruses. Several of these viruses could not be detected by well-known anti-viruses such as Avira, Avast, Norton, Kaspersky and McAfee.