GNSS spoofing

In global navigation satellite systems (GNSS), a spoofing attack attempts to deceive a GNSS receiver by broadcasting fake GNSS signals, structured to resemble a set of normal GNSS signals, or by rebroadcasting genuine signals captured elsewhere or at a different time.^[1] Spoofing attacks are generally hard to detect as adversaries generate counterfeit signals. These spoofed signals are challenging to recognize from legitimate signals, thus confusing ships' calculation of positioning, navigation, and timing (PNT).^[2] This means that spoofed signals may be modified in such a way as to cause the receiver to estimate its position to be somewhere other than where it actually is, or to be located where it is but at a different time, as determined by the attacker. One common form of a GNSS spoofing attack, commonly termed a carry-off attack, begins by broadcasting signals synchronized with the genuine signals observed by the target receiver. The power of the counterfeit signals is then gradually increased and drawn away from the genuine signals.^[1]

Potential use of GPS spoofing against a naval vessel

Even though GNSS is one of the most relied upon navigational systems, it has demonstrated critical vulnerabilities towards spoofing attacks. GNSS satellite signals have been shown to be vulnerable due to the signals’ being relatively weak on Earth’s surface.^[3] A reliance on GNSS could result in the loss of life, environmental contamination, navigation accidents, and financial costs.^[4][5][6] However, since 80% of global trade is moved through shipping companies, relying upon GNSS systems for navigation remains unavoidable.^[7][8]

All GNSS systems, such as the US GPS, Russia's GLONASS, China's BeiDou, and Europe's Galileo constellation, are vulnerable to this technique.^[9] In order to mitigate some of the vulnerabilities the GNSS systems face concerning spoofing attacks, the use of more than one navigational system at once is recommended.^[10]

The December 2011 capture of a Lockheed RQ-170 Sentinel drone aircraft in northeastern Iran may have been the result of such an attack.^[11] GNSS spoofing attacks had been predicted and discussed in the GNSS community as early as 2003.^[12][13][14] A "proof-of-concept" attack was successfully performed in June 2013, when the luxury yacht White Rose of Drachs was misdirected with spoofed GPS signals by a group of aerospace engineering students from the Cockrell School of Engineering at the University of Texas in Austin. The students were aboard the yacht, allowing their spoofing equipment to gradually overpower the signal strengths of the actual GPS constellation satellites, altering the course of the yacht.^[15][16][17]

In 2019, the British oil tanker Stena Impero was the target of a spoofing attack that directed the ship into Iranian waters where it was seized by Iranian forces. Consequently, the vessel including its crew and cargo were used as pawns in a geopolitical conflict. Several shipping companies with vessels navigating around Iranian waters are instructing vessels to transit dangerous areas with high speed and during daylight.^[18]

On October 15, 2023, Israel Defense Forces (IDF) announced that GPS had been “restricted in active combat zones in accordance with various operational needs,” but has not publicly commented on more advanced interference. In April 2024, however, researchers at University of Texas at Austin detected false signals and traced their origin to a particular air base in Israel run by the IDF.^[19]

Russian GPS spoofing

See also: Krasukha § Operational_history, Borisoglebsk-2, and Automatic Dependent Surveillance–Broadcast

In June 2017, approximately twenty ships in the Black Sea complained of GPS anomalies, showing vessels to be transpositioned miles from their actual location, in what Professor Todd Humphreys believed was most likely a spoofing attack.^[17][20] GPS anomalies around Putin's Palace and the Moscow Kremlin, demonstrated in 2017 by a Norwegian journalist on air, have led researchers to believe that Russian authorities use GPS spoofing wherever Vladimir Putin is located.^[17][21]

The mobile systems named Borisoglebsk-2, Krasukha and Zhitel are reported to be able to spoof GPS.^[22]

Incidents involving Russian GPS spoofing include during a November 2018 NATO exercise in Finland that led to ship collision (unconfirmed by authorities).^[23] and a 2019 incident of spoofing from Syria by the Russian military that affected the civil airport in Tel Aviv.^[24][25]

In December of 2022 significant GPS interference in several Russian cities was reported by the GPSJam service; the interference was attributed to defensive measures taken by Russian authorities in the wake of the invasion of Ukraine.^[9]

GPS spoofing with SDR

Since the advent of software-defined radio (SDR), GPS simulator applications have been made available to the general public. This has made GPS spoofing much more accessible, meaning it can be performed at limited expense and with a modicum of technical knowledge.^[26] Whether this technology applies to other GNSS systems remains to be demonstrated.

Prevention

The Department of Homeland Security, in collaboration with the National Cybersecurity and Communications Integration Center (NCCIC) and the National Coordinating Center for Communications (NCC), released a paper which lists methods to prevent this type of spoofing. Some of the most important and most recommended to use are:^[27]

1. Obscure antennas. Install antennas where they are not visible from publicly accessible locations or obscure their exact locations by introducing impediments to hide the antennas.
2. Add a sensor/blocker. Sensors can detect characteristics of interference, jamming, and spoofing signals, provide local indication of an attack or anomalous condition, communicate alerts to a remote monitoring site, and collect and report data to be analyzed for forensic purposes.^[28]
3. Extend data spoofing whitelists to sensors. Existing data spoofing whitelists have been and are being implemented in government reference software, and should also be implemented in sensors.
4. Use more GNSS signal types. Modernized civil GPS signals are more robust than the L1 signal and should be leveraged for increased resistance to interference, jamming, and spoofing.
5. Reduce latency in recognition and reporting of interference, jamming, and spoofing. If a receiver is misled by an attack before the attack is recognized and reported, then backup devices may be corrupted by the receiver before hand-over.

These installation and operation strategies and development opportunities can significantly enhance the ability of GPS receivers and associated equipment to defend against a range of interference, jamming, and spoofing attacks. A system and receiver agnostic detection software offers applicability as cross-industry solution. Software implementation can be performed in different places within the system, depending on where the GNSS data is being used, for example as part of the device's firmware, operating system, or on the application level.^{[citation needed]}

A method proposed by researchers from the Department of Electrical and Computer Engineering at the University of Maryland, College Park and the School of Optical and Electronic Information at Huazhong University of Science and Technology that aims to help mitigate the effects of GNSS spoofing attacks by using data from a vehicles controller area network (CAN) bus. The information would be compared to that of received GNSS data and compared in order to detect the occurrence of a spoofing attack and to reconstruct the driving path of the vehicle using that collected data. Properties such as the vehicles speed and steering angle would be amalgamated and regression modeled in order to achieve a minimum error in position of 6.25 meters.^[29] Similarly, a method outlined by researchers in a 2016 IEEE Intelligent Vehicles Symposium conference paper discuss the idea of using cooperative adaptive cruise control (CACC) and vehicle to vehicle (V2V) communications in order to achieve a similar goal. In this method, the communication abilities of both cars and radar measurements are used to compare against the supplied GNSS position of both cars to determine the distance between the two cars which is then compared to the radar measurements and checked to make sure they match. If the two lengths match within a threshold value, then no spoofing has occurred, but above this threshold, the user is notified so that s/he can take action.^[30]