You might be better off not using SSH, its not mandatory to use it, and if you dont change the password it is very likely that you can get a virus. There was a "Rick Astley" virus a while ago and I got it on my iphone 4 just by using SSH once, then deleting it because i really wasnt interested in using it and i did not change password the 2 days i had it, and i realized i had the virus after phone lagging a lot and some other symptoms and I googled the heck out of solutions and finally got rid of it by deleting files I had to find in the phone system, and re-downloaded terminal and changed the password and then got rid of it again and never used it since.