I often get asked what makes Immunet’s approach to detecting threats different than the mainstream Anti-Virus companies. In a nutshell, our goal is to find threats which are in small parts of our community, analyze them and then protect the whole community from them as fast as possible, often in near real time.
We do not focus on obscure threats, or threats which circulate outside of our community. We are not big fans of the 'boil the ocean' approach to doing Anti-Virus. It works well for reviewers (who test with everything under the sun) but it rarely really helps your community. There is a reason people are still getting viruses and it's time we rethink our (the industry) approach to tackling this problem.
As to 'how' we convict files. All of our current approaches entail communication back and forth with the cloud so that rarely is a decision made in 'decision support isolation’. This allows you to work with the most current, up to the minute, information that we have. Here are some of the approaches we use:
- Generic detection of threats through broad hashing. We look for things that look 'like' threats we know of and try to further analyze them for conviction so we can protect the community. This can also be called a 'heuristic' engine if you like. Our generic engine is ETHOS; we have another planned for May, which is called SPERO.
- Context conviction, this is where we make decisions based off the data we receive about a file in field. From community collected data we can make assumptions about whether a file is a virus or not. For example, did our AV stop working after it was installed? Did the system start to see other viruses after it was installed? Questions like this will often lead to answers, which make us highly suspicious of a file.
- One-to-One conviction, this is where there is a known threat we've collected from the community, through collection trading or gathered from web crawling. For each of these collected (and verified malicious files) we generate a signature. When users do file look-ups this signature is sent to us, if it matches a known threat we convict the file as a virus.
There are a few other ways as well and each of those approaches above could be a daylong chat on their own but that's the mile high view today (March 7, 2010).