Unusual Commands from Subsystem Acting as Bus Controller (1553)

Detection of unusual commands being issued by a subsystem acting as a bus controller, indicating that a threat actor may have escalated privileges or have access to the bus within the flat bus architecture to issue commands from unauthorized subsystems.

STIX Pattern

[x-opencti-bus-master:role = 'subsystem' AND x-opencti-bus-master:commands != 'expected_commands']

SPARTA TTPs

ID Name Description
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.
EX-0014.02 Bus Traffic Threat actors may attempt to target the main or secondary bus onboard the victim spacecraft and spoof their data. The spacecraft bus often directly processes and sends messages from the ground controllers to the various subsystems within the spacecraft and between the subsystems themselves. If a threat actor would target this system and spoof it internally, the subsystems would take the spoofed information as legitimate and process it as normal. This could lead to undesired effects taking place that could damage the spacecraft's subsystems, hosted payload, and critical data.
EX-0014.03 Sensor Data Threat actors may target sensor data on the space vehicle to achieve their attack objectives. Sensor data is typically inherently trusted by the space vehicle therefore an attractive target for a threat actor. Spoofing the sensor data could affect the calculations and disrupt portions of a control loop as well as create uncertainty within the mission thereby creating temporary denial of service conditions for the mission. Affecting the integrity of the sensor data can have varying impacts on the space vehicle depending on decisions being made by the space vehicle using the sensor data. For example, spoofing data related to attitude control could adversely impact the space vehicles ability to maintain orbit.
LM-0002 Exploit Lack of Bus Segregation Threat actors may exploit victim spacecraft on-board flat architecture for lateral movement purposes. Depending on implementation decisions, spacecraft can have a completely flat architecture where remote terminals, sub-systems, payloads, etc. can all communicate on the same main bus without any segmentation, authentication, etc. Threat actors can leverage this poor design to send specially crafted data from one compromised devices or sub-system. This could enable the threat actor to laterally move to another area of the spacecraft or escalate privileges (i.e., bus master, bus controller)