Scanning should be fine; trying to access them becomes dubious; bruteforcing the login could lead to arrest.
One of the core apps had a control port that implemented HTTP. Unfortunately, my GET hit a route that didn't exist, and that caused a small memory leak every time.
Nothing too bad happened; the leak was slow, and even though the app stayed up many months at a time, we did notice the leak and figured out what was causing it.
As others have stated elsewhere, I've seen completely 'easy going' TCP connections to embedded devices cause immediate crashes.
I wouldn’t guess they would add double sensors for all that information.
Or did you mean well protected, instead of literal air gap?
Fiber optic connections aren't required, anything with separate transmit and receive lines can be turned into a data diode (as long as the protocols used permit it). RS232 null modem cables with the RX lines disconnected are a classic.
The flight critical systems would be isolated from in-flight entertainment system (IFE). The IFE probably has a listen-only tap to flight metric info on an ARINC databus from the flight computer. I did a quick search and looks like 787 uses ARINC 667, a fiber optic interconnect.
> These special conditions are issued for the Boeing Model 787-8 airplane. This airplane will have novel or unusual design features when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. The architecture of the Boeing Model 787-8 computer systems and networks may allow access to external systems and networks
[1] https://www.federalregister.gov/documents/2007/12/28/E7-2507...
Agree the IFE could crash, but can't see how there is even a remote risk to critical systems, or any risk to the IFE that isn't solved by (yet another) reboot of it.
In the UK for example, the computer misuse act says that using any tool with the intent of accessing a system (without actually doing so, let alone doing so successfully) is an offence.