The question is simple, How does Panda Cloud Antivirus work?
I mean how can it detect an infected file without having an offline database or sending the actual file to be checked by a remote server?
closed as not constructive by Nifle, Paul, Diogo, Mokubai♦, Simon Sheehan Jul 15 '12 at 0:38
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Webapps are quite complex these days and technologies such as Flash, Java, ActiveX, Silverlight and others allow a great number of features that a virus scanner would need.
Java in particular is a full blown programming language and if you give it the permissions to run on your machine has the same power and abilities as any locally run application.
If it were programmed in Java or similar then it would simply download the core application in your browser and then load the virus definitions from "the cloud". It would then run locally as if it were your standard virus scanner. All it would lack would be the administrator privileges that a properly installed virus scanner would have.
ActiveX would have allowed similar power but I believe its use is deprecated now. There are probably other tools that can do similar.
I suspect that the "cloud" feature is simply a constantly evolving virus definition database with some heuristics involved, if one computer user determines something is a threat then that detection is immediately pushed to other computers.
The "Cloud" is simply the current hot phrase to try and sell your product. Marketing BS basically.