Re Forbes' article, "How to Hijack 'Every iPhone iIn The World' ", here is Forbes' take on the present issue under discussion:
Researcher Says He's Found Hackable Flaws In Airplanes' Navigation Systems (Update: The FAA Disagrees) - Forbes
The claim has been made that the author of this presentation could send radio signals to aircraft such that aircraft so hacked could be commanded to change direction, altitude and speed.
So far, no one has even outlined the steps and process let alone detailed the unbroken chain of technical events which would lead to an Android phone taking control of an aircraft beyond the crew's awareness or ability to counter the hack.
For the reasons I have posted above and in subsequent posts I suggest that the challenges are almost insurmountable when it comes to actually manipulating the flight controls as claimed by Mr. Teso.
That ACARS, ADS and CPDLC are potentially hackable is not in dispute. It is the extent of the threat that requires delineation, and I propose that such threats do not encompass actual control of the aircraft.
Hacking instrument displays such as Primary Flight Displays and Nav Data Displays with examples such as TCAS & GPWS indications still require assessment, resolution and action by crew members, and are not automatic responses by the autoflight systems. The implementation of providing uploaded data to make such a system "think" there is either an intruder (TCAS) or a legitimate EGPWS warning, is a herculian undertaking which would yield very little cockpit effect and zero aircraft effect. The "return" on the "investment" required just isn't there.
Route changes require manual executions using the FMS keyboard interface; no autoflight system changes altitude without manual input by the flight crew; speed changes are an autothrust function but inputs are reasonableness-checked by the FMS.
PJ2