From my book Data and Goliath:
...when I was working with the Guardian on the Snowden documents, the one top-secret program the NSA desperately did not want us to expose was QUANTUM. This is the NSA's program for what is called packet injection -- basically, a technology that allows the agency to hack into computers. Turns out, though, that the NSA was not alone in its use of this technology. The Chinese government uses packet injection to attack computers. The cyberweapons manufacturer Hacking Team sells packet injection technology to any government willing to pay for it. Criminals use it. And there are hacker tools that give the capability to individuals as well. All of these existed before I wrote about QUANTUM. By using its knowledge to attack others rather than to build up the Internet's defenses, the NSA has worked to ensure that anyone can use packet injection to hack into computers.
And that's true. China's Great Cannon uses QUANTUM. The ability to inject packets into the backbone is a powerful attack technology, and one that is increasingly being used by different attackers.
Even when technologies are developed inside the NSA, they don't remain exclusive for long. Today's top-secret programs become tomorrow's PhD theses and the next day's hacker tools.
I could have continued with "and the next day's homework assignment," because Michalis Polychronakis at Stony Book University has just assigned building a rudimentary QUANTUM tool as a homework assignment. It's basically sniff, regexp match, swap sip/sport/dip/dport/syn/ack, set ack and push flags, and add the payload to create the malicious reply. Shouldn't take more than a few hours to get it working. Of course, it would take a lot more to make it as sophisticated and robust as what the NSA and China have at their disposal, but the moral is that the tool is now in the hands of anyone who wants it. We need to make the Internet secure against this kind of attack instead of pretending that only the "good guys" can use it effectively.
End-to-end encryption is the solution. Nicholas Weaver wrote:
The only self defense from all of the above is universal encryption. Universal encryption is difficult and expensive, but unfortunately necessary.
Encryption doesn't just keep our traffic safe from eavesdroppers, it protects us from attack. DNSSEC validation protects DNS from tampering, while SSL armors both email and web traffic.
There are many engineering and logistic difficulties involved in encrypting all traffic on the internet, but its one we must overcome if we are to defend ourselves from the entities that have weaponized the backbone.
And this is true in general. We have one network in the world today. Either we build our communications infrastructure for surveillance, or we build it for security. Either everyone gets to spy, or no one gets to spy. That's our choice, with the Internet, with cell phone networks, with everything.