Question of the week: What is the antivirus setting called DeepScreen?
DeepScreen is a new technology inside avast! Antivirus 2014. When you are about to run a suspicious program which is not yet known to the other core antivirus technologies, DeepScreen is invoked. Its task is to simply distinguish between good and bad software. Although it seems obvious and simple, it is not.
How DeepScreen uses The Force for good
This (magic) technology is served by two software components (the Jedi, if you will) which work hand-in-hand. One of them is well known from the past: The avast! Sandbox.
When a file is “DeepScreened,” it is actually run in the Sandbox, which is mainly responsible for keeping things isolated while watching for various high-level events and behavior of the program running. For example, it monitors the system call invocation and overall behavior of the program which is being executed. This seems to be just enough to distinguish between the Dark Side and the Light Side of the Force, but unfortunately, it is not that simple.
Firstly, how can you tell good and bad behavior apart? There are plenty of legitimate software products that use "weird" techniques to protect themselves. On the other hand, there is a bunch of malware samples that look innocent and behave well.
Secondly, malware is used to hiding away from the vigilant eyes of the Sandbox. The most common and powerful technique is encryption. In fact, there are more ways of encrypting and packing these well - known bad guys and rendering them undetectable than there are distinct malware samples.
SafeMachine: The new Jedi Order
With the latest version of avast! Antivirus 2014, this technology is fully involved in fighting the bad guys. Whenever DeepScreen runs something in the Sandbox, it also performs binary instrumentation of the process.