A signal source detected in the ocean between authorized ground stations resulted in a failure, leading to an 'invalid' classification. A signal is classified as 'valid' when the following conditions are met: the transponder operates at the correct frequency and power level, all signal characteristics align with expected parameters, and command lock is achieved, the signal originates from an authorized and expected location.

STIX Pattern

[x-opencti-signal_char:value = 'invalid']

SPARTA TTPs

ID	Name	Description
IA-0008	Rogue External Entity	Threat actors may gain access to a victim spacecraft through the use of a rogue external entity. With this technique, the threat actor does not need access to a legitimate ground station or communication site.
IA-0008.01	Rogue Ground Station	Threat actors may gain access to a victim spacecraft through the use of a rogue ground system. With this technique, the threat actor does not need access to a legitimate ground station or communication site.
EX-0016	Jamming	Threat actors may attempt to jam Global Navigation Satellite Systems (GNSS) signals (i.e. GPS, Galileo, etc.) to inhibit a spacecraft's position, navigation, and/or timing functions.
EX-0016.03	Position, Navigation, and Timing (PNT)	Threat actors may attempt to jam Global Navigation Satellite Systems (GNSS) signals (i.e. GPS, Galileo, etc.) to inhibit a spacecraft's position, navigation, and/or timing functions.
EX-0016.01	Uplink Jamming	An uplink jammer is used to interfere with signals going up to a satellite by creating enough noise that the satellite cannot distinguish between the real signal and the noise. Uplink jamming of the control link, for example, can prevent satellite operators from sending commands to a satellite. However, because the uplink jammer must be within the field of view of the antenna on the satellite receiving the command link, the jammer must be physically located within the vicinity of the command station on the ground.* *https://aerospace.csis.org/aerospace101/counterspace-weapons-101
EX-0016.02	Downlink Jamming	Downlink jammers target the users of a satellite by creating noise in the same frequency as the downlink signal from the satellite. A downlink jammer only needs to be as powerful as the signal being received on the ground and must be within the field of view of the receiving terminal’s antenna. This limits the number of users that can be affected by a single jammer. Since many ground terminals use directional antennas pointed at the sky, a downlink jammer typically needs to be located above the terminal it is attempting to jam. This limitation can be overcome by employing a downlink jammer on an air or space-based platform, which positions the jammer between the terminal and the satellite. This also allows the jammer to cover a wider area and potentially affect more users. Ground terminals with omnidirectional antennas, such as many GPS receivers, have a wider field of view and thus are more susceptible to downlink jamming from different angles on the ground.* *https://aerospace.csis.org/aerospace101/counterspace-weapons-101
EX-0014	Spoofing	Threat actors may attempt to spoof the various sensor and controller data that is depended upon by various subsystems within the victim spacecraft. Subsystems rely on this data to perform automated tasks, process gather data, and return important information to the ground controllers. By spoofing this information, threat actors could trigger automated tasks to fire when they are not needed to, potentially causing the spacecraft to behave erratically. Further, the data could be processed erroneously, causing ground controllers to receive incorrect telemetry or scientific data, threatening the spacecraft's reliability and integrity.
DE-0002	Prevent Downlink	Threat actors may target the downlink connections to prevent the victim spacecraft from sending telemetry to the ground controllers. Telemetry is the only method in which ground controllers can monitor the health and stability of the spacecraft while in orbit. By disabling this downlink, threat actors may be able to stop mitigations from taking place.