I was reading the Wikipedia article about TAO and there is written that:
Details on a program titled QUANTUMSQUIRREL indicate NSA ability to masquerade as any routable IPv4 or IPv6 host. This enables an NSA computer to generate false geographical location and personal identification credentials when accessing the Internet utilizing QUANTUMSQUIRREL.
I know that of course is possible to spoof the IP address of a packet. That is, to send out a packet with a fake "sender" IP address. But then the answer by the server should arrive to the "sender" IP address it sees, not the "real" one.
How, from a technical point of view, can the NSA act as an arbitrary IP address, meaning they can send and receive packets from and to and IP address?
What is the computer science technique they are using?
When they open the terminal, what are the commands they type? What third party utilities they are using?
Would the NSA require cooperation from other parties to achieve this?