Silence on the Wire

Back to System Fingerprinting

Indeed, a couple of truly fascinating consequences result from our ability to map out the dynamics of a sequence number generator in a particular system and from the fact that most implementations exhibit certain more or less unique phase-space patterns. The most obvious trick is the application of ISN probing to old-school system fingerprinting.

By observing a couple of sequence numbers acquired from a remote system (for example, when a party attempts to establish several connections to a server) you can attempt to find an attractor to which this data fits best, by comparing the observed sample against a library of known attractors. (The numbers don’t need to be predictable using the attack technique described; the ...