This is critically different. Part of the issue with intelligence agencies using exploits is that using an exploit often means sending it to somebody untrusted (often the target of the attack!)
c2 servers and machines used to deliver exploits are necessarily connected to the internet, and often are from low-tier commercial hosting services- c2.tao.nsa.gov is a bit too easy to attribute, as it turns out.
An IM backdoor could rely on a key kept in an HSM, across an airgapped network allowing only encrypted messages in one direction and decryptions in the other. Assuming the airgapped side only needs to decrypt something like a LEAF, communication over something like serial means almost zero attack surface would be exposed to anything reachable from the internet.
So, yes, you probably can control an IM backdoor significantly better than the NSA can control their offensive tools. Will the government manage that? Ehhhhhhh.
There are much better arguments against an IM backdoor. Saying "the government can't keep it secure" is especially problematic because if that's perceived as the anti-backdoor argument and the government comes up with a secure way to implement a backdoor...well, then, why not do it?
Again, the Shadow Brokers stuff is "a staging server was compromised", which just isn't that related to the problem of securing an IM backdoor. Snowden leaked information he had access to, but measures like storing the key in an HSM (and not allowing it to be extracted) largely mitigate that threat.
Do you have somewhere I can read on the Shadow Brokers' compromised staging server? I was under the impression that actual source code was released (implying a much deeper break) but seems I was wrong, as no article I could find through Google mentions a source code leak -- but none mention a staging server either.
it shouldn't need to touch almost any code in the OS- the UART can pretty much receive raw bytes. There's no signalling layer besides start/stop. The serial "stack" is tiny- as long as you don't somehow manage to involve the OS's terminal emulation layer, which should generally not be a concern- compared to TCP/IP.
there's no risk of accidentally leaving a service listening on the machine
it's incompatible with normal network connections- don't really have concerns about somehow connecting it to the Internet.
all network adapters on the machine can be disabled, rather than "only one network adapter"
But the main point is the reduction of attack surface going from a general purpose networking stack to a bidirectional stream of bytes.
c2 servers and machines used to deliver exploits are necessarily connected to the internet, and often are from low-tier commercial hosting services- c2.tao.nsa.gov is a bit too easy to attribute, as it turns out.
An IM backdoor could rely on a key kept in an HSM, across an airgapped network allowing only encrypted messages in one direction and decryptions in the other. Assuming the airgapped side only needs to decrypt something like a LEAF, communication over something like serial means almost zero attack surface would be exposed to anything reachable from the internet.
So, yes, you probably can control an IM backdoor significantly better than the NSA can control their offensive tools. Will the government manage that? Ehhhhhhh.
There are much better arguments against an IM backdoor. Saying "the government can't keep it secure" is especially problematic because if that's perceived as the anti-backdoor argument and the government comes up with a secure way to implement a backdoor...well, then, why not do it?