Rather than go through the bureaucratic fight to move the attack logic into “system low” (and co-located on the wiretap), the NSA sought to work around it in the case of QUANTUMHAND. Instead of targeting just any web connection for exploitation, it targeted persistent “push” connections from Facebook, where a user’s browser would leave an idle connection open, waiting for a command from the server.
This way, even the slow, broken, classified architecture could exploit Facebook users. Sadly for NSA and GCHQ (and FSB, and DGSE, and every other spy agency), Facebook turned on encryption a few months ago, which should thwart this attack.
The biggest limitation on QUANTUM is location: The attacker must be able to see a request which identifies the target. Since the same techniques can work on a Wi-Fi network, a $50 Raspberry Pi, located in a Foggy Bottom Starbucks, can provide any country, big and small, with a little window of QUANTUM exploitation. A foreign government can perform the QUANTUM attack NSA-style wherever your traffic passes through their country.