Net_Runner's through the use of extensive cybernetics and brain-computer interfaces allow them to access, infiltrate, and/or manipulate pre-established systems as well as others augments and cybernetics. A netrunner knows the ins and outs of computer systems, the programming languages, how to write or mod a killer virus, as well as interface with vehicle systems and automations. Many netrunners are free agents working only for themselves, but a few have signed their own pacts with megacorps and work to keep corporate data fortresses solid and impenetrable.
Through the use of direct interfacing your have to gain a comprehensive knowledge of computer systems exploring, manipulating, and modifying them given enough time and familiarization.