HACNet Simulation-based Validation of Security Protocols Vinay Venkataraghavan Advisors: S.Nair, P.-M. Seidel HACNet Lab Computer Science and Engineering Department {venkatra, Nair,

HACNet Security Protocols: Properties and Services

HACNet Problems and flaws in Security Protocols

HACNet The need for Verification and Validation Verification and validation involves the systematic analyses of protocols in order to verify properties and detect errors.

HACNet Hierarchy and Stages in Validation and Verification

HACNet Formal Verification Specification language used to represent entities, actions, and events. Properties to be checked are represented as CTL or LTL formulas. Model checker checks the state space to prove the validity of properties. Approach models belief’s held by entities, and ensures they are not violated. The protocol is represented as a finite automata. The model checker, verifies if the language representing the property is accepted. Formal verification and methods involves the mathematical analysis of systems in order to verify correctness.

HACNet Complexity, Problems and drawbacks of Formal Verification

HACNet Simulation-based Approach Automated approach to validation. Protocol modeled, as a set of asynchronous communicating Finite State Machines. Each entity tracks its knowledge in terms of keys, nonces and message types. Finite number of states, requiring a finite number of runs. Protocol traces are simulated in order to check for property violations. A trace of the incorrect execution is generated if it exists. Unlike systems based on logics, do not have to interpret belief’s about each message.

HACNet Advantages of simulation Reflects a strong correspondence with the specification. Accurately represents implementation semantics. Efficiently represents delay, link failure, error etc. Captures the notion of time precisely. Intruder can be modeled as required. Easily check properties such as confidentiality, authentication, and integrity. Simulation better suited for large protocols. More intuitive for verifying properties.

HACNet Architectural Model Protocol Validator Intruder models Algorithms -State space exploration - guiding algorithms - error detection algorithms - validation algorithm FSM representation of Processes Validation algorithm Protocol implementation based abstractions Simulator Guide simulation Protocol execution Approach: -Simulate the model based upon the FSM representation by applying the validation method - Report anomalous execution traces, errors, flaws etc. Specification Implementation Attack model Execution flaws, errors

HACNet Modeling Security Properties IDI, KPI, KAI, Messages-I Initiator IDR, KAA, KPA, Messages-A Intruder Responder IDA, KPR, KAR, Messages-R Confidentiality: During simulation the intruder can never learn the private keys of the initiator or responder. Channel Authentication: The meta channel within the Meta Authentication framework will be used to verify authentication properties. * Meta Channel Timing : Timing properties may be checked by the use of scheduled interrupts, and delay specification models. * Meta Authentication framework is designed by our group for the verification of authentication protocols and properties.

HACNet Intruder model capabilities Randomly initiates attacks during protocol execution. Very powerful tool in detecting attack traces. Combine with an attack model to target the specific faults and property violations.

HACNet Attacks Needham Schroeder Public Key Protocol Oracle attack Parallel attack Replay attack

HACNet Results and Conclusion Protocol developed and simulated in OPNET. 140 runs were made, with intruder conducting random attacks. All the attacks were detected and various properties demonstrated. Configuration demonstrated was free of flaws. Simulation is a valuable approach for protocol validation. It is not guaranteed to detect errors. Need to run simulations for incrementally longer durations, with different attack models. Need to propose a guiding algorithm in detecting error states. Intuitive and simpler method to security protocol validation. RESULTSCONCLUSIONS

HACNet Future Work