Learn English – Serious word for ‘a bad guy’

formalitynounssingle-word-requests

I was trying to raise awareness of XSS attacks on a website, by launching a harmless XSS attack and showing the follow message if users fell for it:

IT WAS AN XSS ATTACK!

HAD IT BEEN MADE BY A BAD GUY, YOUR ACCOUNT WOULD HAVE BEEN STOLEN.

I want my message to sound serious, but 'a bad guy' seems informal. I quickly Googled a list of synonyms, but, as a non-native speaker, couldn't figure out which fits more in this content. Can you provide suggestions?

Well, maybe I should tell my professor his site is flawed directly.

Best Answer

I would change the wording to refer more to the attack than the person.

"Had it been malicious, your account would have been stolen."