In theory, perfect software applications are possible but in real life, they don't exist. When attackers know the software, they can send payloads to exploit vulnerabilities and run any arbitrary code ...
Can I attack a PC via the VGA port? Is VGA one way or does it accept data from the other side? How about HDMI or DVI? And if so, are there known malware or PoCs to do that? or is it theoretically ...
Using Passware Forensic Toolkit you can extract the bitlocker key using live memory dumping through Firewire (either by using an existing Firewire port, or by inserting an pcmcia/expresscard ...
What are the track records of popular Hardware Security Modules (HSMs)? Have any been found vulnerable to hacking via creative use of the API, timing or power-monitoring attacks, etc?