Undetectable Timing-Attack on Linear State-Estimation by Using Rank-1 Approximation

Abstract

Abstract-Smart-grid applications based on synchrophasor measurements have recently been shown to be vulnerable to timing attacks. A fundamental question is whether timing attacks could remain undetected by bad-data detection algorithms used in conjunction with state-of-the-art situational-awareness state estimators.In this paper, we analyze the detectability of timing attacks on linear state-estimation. We show that it is possible to forge delay attacks that are undetectable. We give a closed form for an undetectable attack; it imposes two phase offsets to two or more synchrophasor-based measurement units that can be translated to synchrophasors' time delays. We also propose different methods for combining two-delays attacks to produce a larger impact. We simulate the attacks on a benchmark powertransmission grid, we show that they are successful and can lead to physical grid damage. To prove undetectability, we use classic bad-data detection techniques such as the largest normalized residual and the χ 2 -test.

Integration of Failure Detector in Bias Filter for Estimation of False Data Injection Cyberattacks

“…It is shown that a time-variable FDI is able to evade detection via existing detection methods [21]- [22]. Reference [23] considered the cyber-attacks on GPSsynchronized measurements, which gives the attackers the ability of creating time-variable FDIs simply by shifting the measurements in time. Time-varying FDI parameters were also considered in [13]- [14], where it is argued that once the attackers have accessed the system to impose constant FDIs, they can also impose time-variable FDIs with the same efforts and equipment.…”

Security Measures for Grids against Rank-1 Undetectable Time-Synchronization Attacks

“…We now introduce the system model that is the same as in [8], [9], we present the attack model and we define rank-1 UTSAs.…”

“…These are physical attacks that are neither prevented nor detected by the cryptographic tools used by the synchronization protocol. As a result, the phase of phasor measurements is shifted, which can non-negligibly impact the state estimation of the system, as it was shown in [8], [9].…”

“…In contrast, it is possible to remotely alter the time reference of PMUs via GPS spoofing [16] or with delay boxes [7], thus impacting several smart-grid applications, including the state estimation. The authors of [8] propose a strategy to compute undetectable timesynchronization attacks (UTSAs) against vulnerable pairs of PMUs, each measuring a single phasor. They also discuss how vulnerable pairs of PMUs can be targeted simultaneously in order to maximize an attack.…”

“…The attack strategies and vulnerability conditions proposed in [8] and [9] require that each offset alters a single PMU that measures a single phasor. Yet, PMUs are capable of measuring several phasors, and several PMUs can share the same time-reference.…”