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The precision time protocol (PTP) is considered as one of the most favorable mechanisms for providing unified and precise time at the substation level in the smart grid. Nevertheless, PTP was shown to be vulnerable to cyber-attacks targeting its components and synchronization services. In this article, we capitalize on the theory and outcome of our previous work to contribute a more complete solution that addresses PTP cyber security. We propose to close the PTP loop through an extension that introduces new functionality and messages. This extension covers the PTP attack surface and enables the detection of attacks on PTP time synchronization. We formally model and verify the proposed extension using UPPAAL model checker. In addition, we validate the proposed extension using Omnet++ simulation. The evaluation demonstrates that our approach preserves PTP functionality, while successfully detecting cyber attacks against PTP components in a timely manner. [ABSTRACT FROM AUTHOR]

Time distribution mechanisms favored for use in the smart grid, such as precision time protocol (PTP), were not designed with security in mind, and thus suffer several security vulnerabilities. PTP is vulnerable to fake timestamp attacks through master impersonation and sync message injection. Such an attack will synchronize clocks to a false time reference. In this letter, we consider an IEC 61850 substation and propose an approach to detect fake timestamps communicated through false PTP sync messages. This approach builds on top of existing network and system management solutions. We introduce a new simple network management protocol data objects to monitor PTP functionality and detect the existence of fake timestamps in a PTP synchronized network. The approach is implemented on a testbed. The collected results demonstrate its ability to protect against fake timestamp attacks. [ABSTRACT FROM AUTHOR]

Smart grid applications demand the availability of a reliable and accurate time signal. Measurements and events need to be correctly aligned to enable proper actions and decisions. Precision time protocol (PTP) is the favored protocol for time distribution across smart grid domains. The correct functionality of PTP is of paramount importance and its security is of high priority. To harden its security, detection, and prevention mechanisms against attacks targeting PTP are needed. In this paper, we propose detection and mitigation mechanisms against the known PTP delay attack. We apply model checking to quantify the effect of the delay attack. Moreover, the validity of the proposed mechanism is formally proven. The suggested approach is tested on a physical system. The collected results support the usefulness of the mechanism in detecting the delay attacks targeting PTP, and preserving the system functionality. [ABSTRACT FROM AUTHOR]