Perimeter security cable barriers are widely used by various agencies all over the world to defeat threat vehicle penetration. New barrier designs require crash test validation prior to implementation. Full-scale vehicular crash tests are costly, whereas designs via finite element simulations are time consuming and require specialized skills. Based on full-scale crash tests, an innovative and simple algorithm has been developed to model the progressive failure of security cable barriers. A multi-body approach based on the first principles of physics was developed to substantially reduce computer runtime. The solution algorithm uses a large number of small time steps. Nonlinear vehicle and cable forces and deformations are calculated based on compatibility conditions. This methodology has been validated against three full-scale crash tests. This cable barrier model, displaying simulation results graphically in a time series, provides realistic response parameters of a security cable barrier design in less than 10 minutes of runtime with reasonable accuracy.