I am not that familiar with security and malware analysis, but I know it is theoretically possible to embed a malware into files like video, audio ...
Say that someone managed to embed a malware into an mp4 file and send it via gmail.
I have the following questions.
Is it easy to bypass the google security that is implemented in gmail so that it will not be detected as virus/malware by gmail?
Once, downloaded the video, how to check whether it contains a malware/virus or not (other methods than using virustotal...)?
Is it possible that the malware can infect multiple OS (Windows and Linux: mainly Ubuntu)?