There are no anti-virus or software that are alike. There are "basic firewalls" that come with certain tweaks for added security in terms of encryption such as GNU Privacy Guard for OpenPGP, but other than that, unless you forcefully install a virus/malware/spyware, or pirate, you should have no worries about anything in terms of security. Other than that, if you have OpenSSH installed, changing your password is a must.