I think everyone has come across a malicious app at least one time and whether or not they downloaded it is another story. I like to make use of my older phones that I no longer use if I am not sure about an app just to be cautious.
What are some signs people should be aware of when it comes to malicious apps to better protect themselves, their phones, and their data?
Do you mean on phones? If so just pay attention to the permissions it asks for. If it doesn't make sense for what it is, it is likely malicious.
@glitch72 I was going to mention this. They have a hard time getting through without you knowing on phones. I just don't download anything that asks for permissions that make no sense to the actual app and even then, you want to be careful. I prefer apps that don't need any permissions.
I always check for paid reviews as well as unusual data usage. If you have a basic understanding of how much an app should use, the ones that are double or triple that is a massive red flag and likely had backdoor programming on it.
There are always going to be ways around apps and sneaking things into them or extracting items from your phone through them. I make use of F-Droid. They vet things better and you are able to get real reviews on there.