A security metric measures or asse s the extent to which a

system meets its security objectives. Since meaningful quantitative

security metrics are largely unavailable, the security

community primarily uses qualitative metrics for security.

In this paper, we present a novel quantitative metric for the

security of computer networks that is based on an analysis of

attack graphs. The metric measures the security strength of

a network in terms of the strength of the weakest adversary

who can successfully penetrate the network.-A security metric measures or assesses the extent to which a

system meets its security objectives. Since meaningful quantitative

security metrics are largely unavailable, the security

community primarily uses qualitative metrics for security.

In this paper, we present a novel quantitative metric for the

security of computer networks that is based on an analysis of

attack graphs. The metric measures the security strength of

a network in terms of the strength of the weakest adversary

who can successfully penetrate the network.