So basically what you're suggesting is this e virus like Stuxnet that sweetie's harping about is very difficult to introduce into a Chinese IADS & that it's something which can be done for less sophisticated IADS .
Please note sweetie . Learn something constructive from the above write up or come up with an informed rebuttal instead of making a nuisance of yourself out here. Ja ? @Innominate
Let's leave nationality, it makes things emotional, defensive, egoistic, arrogant.
All of us want our offence & defence both to succeed, right? So does the enemy.
From purely tech PoV, for successfull hack, the H/w & S/w aspects of target should be known otherwise how to start in 1st place also is not known.
Secret custom communication protocol.
Secret custom multiple security protocols.
Secret, changing frequency hopping pattern.
Secret, changing passocdes & encryption keys.
Secret H/w architecture.
All wrong pattern of 0s & 1s will be detected & rejected, initially.
So the 1st step of handshake & synchronisation will fail.
Then, spoofing, copying & masquerading like imposter can get us in BUT very limitedly.
The encryption keys alone makes things impossible bcoz they can be 128/256/512 bit leading to billions of combinations.

A Super-computer with AI & brute force attack focussing all its power on breaking the key can also take years.

This is not guessing our lost email, FB account password with unlimited attempts.
In military, just 1 wrong attempt is enough for suspicion. It can be relaxed to 2, 3 or fw more attempts, may be, IDK exactly, considering jamming, poor signal strength, cross-talk, etc.
An entire industry is dedictaed to cyber-security.
REAL LIFE has spies, BUT is NOT like MISSION IMPOSSIBLE, SWORDFISH or any other spy/hack movie.