Where are good places to look for internships? (3rd year undergrad here)

I want to do an internship over the summer of 2020, and am going into my 3rd year in college right now. What are some good companies to look into that do internships? Or the best way to find them? I've taken only the basic classes right now since I'm a transfer, but I know that I want to do security and am much more inclined to work in the private sector than for defense contractors or anyone requiring a clearance.