Is this weird offensive (or defensive, I'm not sure) security idea even possible? Or is this sci-fi already?
So I am still a beginner in cybersecurity, tbh I still don't know whether to specialize in defensive security or offsec operations; my passion is obviously in offsec operations (and I'm pretty sure a large majority of us as well), but defensive security is where job stability is. I am interested in both, just with passion and my weird curiosities learning towards offsec.
So I was just thinking of random stuff awhile ago like some interesting things I want to be able to do after having years of experience of self-studying and experience, in either defensive or offensive security, just for fun. Maybe I could even make it as a research project if I do graduate studies, or something. But primarily I just thought of this just for fun but I was also wondering if at the same time, if it is still within the bounds of computing (?)
Is it possible for like, for example, if I send someone a text message in a message app (messenger, telegram, line, whatever), or to make it simpler I guess we could use email, if someone opens that, but it contains maybe a simple message, or random gibberish, or a content, but the person just views it, marks it as spam, doesn't do anything with it but opened it. But it turns out, the (malware? is it right to call malware?) already has started, like maybe the OS has been tricked and it executed now? And the person does not know this, like the attacker can maybe see "everything" what the user is doing, being able to control it is an extra like maybe go beyond it, but that's the general idea. Maybe it could be used for espionage or something.
Idk how to describe it really, but like for those professionals reading this, is this even real and possible? I thought maybe this delves into sci-fi now or I don't know; I lack the vocabulary and knowledge yet to explain these things, nor I don't even know what to search for this without putting that bunch of explanation, but any help is appreciated.