Blank Text Message from random number - is it a virus?

So I just got a blank text message from some number that I don't know. My worry is that this is some sort of intrusion attempt. My understanding is whenever I receive a text message, or a message with media, my phone automatically downloads it. So me receiving a blank text message from some unknown number leads me to believe that there was some sort of virus attached to the message and when the phone downloads the message, it will download that virus automatically. So my questions are: - Is it possible that this is a virus? - How can I check to see if my phone has a virus? - Is there a way to detect an intrusion attempt so that my phone will tell me if something is happening that shouldn't be?