CS558: Network Security
- 9.2 (b,d)
- Consider an active attacker Igor who is capable of inserting packets into
connection between Alice and Bob, and can forge the source (and destination;
so in particular, Igor can insert packets in such a way that they
appear to come from Alice) of these packets. But Igor's ability to spoof
is not strong enough to receive packets destined to
Alice (or to Bob). How can we defend against Igor (with the least costs)?
In particular, do we need signatures
and PKI (Public Key Infrastructure: the certificates and the Certificate
Authorities to issue them)? What about if Igor joins forces with his
friend Keila who can kill any connection (in one or both directions, that
is she can make it so that no packets get from Alice to Bob; the spoofed
packets from Igor to Bob, pretending to be from Alice, would still get through)?