Data Exfiltration Detected During Scheduled Communication Windows

Detection of larger-than-expected data packets sent during scheduled spacecraft communication windows, indicating that a compromised ground system may be exfiltrating data under the guise of legitimate operations.

STIX Pattern

[network-traffic:direction = 'downlink' AND network-traffic:data_size > 'expected_size']

SPARTA TTPs

ID Name Description
IA-0007 Compromise Ground System Compromising the ground segment gives an adversary the most direct path to first execution against a spacecraft. Ground systems encompass operator workstations and mission control mission control software, scheduling/orchestration services, front-end processors and modems, antenna control, key-loading tools and HSMs, data gateways (SLE/CSP), identity providers, and cloud-hosted mission services. Once inside, a threat actor can prepare on-orbit updates, craft and queue valid telecommands, replay captured traffic within acceptance windows, or manipulate authentication material and counters to pass checks. The same foothold enables deep reconnaissance: enumerating mission networks and enclaves, discovering which satellites are operated from a site, mapping logical topology between MOC and stations, identifying in-band “birds” reachable from a given aperture, and learning pass plans, dictionaries, and automation hooks. From there, initial access to the spacecraft is a matter of timing and presentation, injecting commands, procedures, or update packages that align with expected operations so the first execution event appears indistinguishable from normal activity.
IA-0009 Trusted Relationship Adversaries obtain first execution by riding connections that the mission already trusts, formal interconnections with partners, vendors, and user communities. Once a third party is compromised, the actor inherits that entity’s approved routes into mission enclaves: VPNs and jump hosts into ground networks, API keys into cloud tenants, automated file drops that feed command or update pipelines, and collaboration spaces where procedures and dictionaries circulate. Because traffic, credentials, and artifacts originate from known counterparts, the initial execution event can appear as a routine payload task, scheduled procedure, or software update promoted through established processes.
IA-0009.01 Mission Collaborator (academia, international, etc.) Missions frequently depend on distributed teams, instrument builders at universities, science operations centers, and international partners, connected by data portals, shared repositories, and federated credentials. A compromise of a collaborator yields access to telescience networks, analysis pipelines, instrument commanding tools, and file exchanges that deliver ephemerides, calibration products, procedures, or configuration tables into mission workflows. Partners may operate their own ground elements or payload gateways under delegated authority, creating additional entry points whose authentication and logging differ from the prime’s. Initial access emerges when attacker-modified artifacts or commands traverse these sanctioned paths: a revised calibration script uploaded through a science portal, a configuration table promoted by a cross-org CI job, or a payload task submitted via a collaboration queue and forwarded by the prime as routine work. Variations in process rigor, identity proofing, and toolchains across institutions amplify the attacker’s options while preserving the appearance of legitimate partner activity.
IA-0009.02 Vendor Vendors that design, integrate, or support mission systems often hold elevated, persistent routes into operations: remote administration of ground software and modems, access to identity providers and license servers, control of cloud-hosted services, and authority to deliver firmware, bitstreams, or patches. Attackers who compromise a vendor’s enterprise or build environment can assume these roles, issuing commands through approved consoles, queuing updates in provider-operated portals, or invoking maintenance procedures that the mission expects the vendor to perform. Some vendor pathways terminate directly on RF equipment or key-management infrastructure; others ride cross-account cloud roles or managed SaaS backends that handle mission data and scheduling.
EXF-0001 Replay The adversary re-sends previously valid commands or procedures to cause the spacecraft to transmit data again, then captures the resulting downlink. Typical targets are recorder playbacks, payload product dumps, housekeeping snapshots, or file directory listings. By aligning replays with geometry (e.g., when the satellite is in view of actor-controlled apertures) and with acceptance conditions (counters, timetags, mode), the attacker induces legitimate transmissions that appear routine to operators. Variants include selectively replaying index ranges to fetch only high-value intervals, reissuing subscription/telemetry-rate changes to increase data volume, or queueing playbacks that fire during later passes when interception is feasible.
EXF-0003.02 Downlink Exfiltration The attacker records spacecraft-to-ground traffic, real-time telemetry, recorder playbacks, payload products, and mirrored command sessions, to obtain mission data and health/state information. With sufficient signal quality and protocol knowledge, frames and packets are demodulated and extracted for offline use; where protection exists only on uplink or is inconsistently applied, downlink content may still be in clear. Downlinked command echoes, event logs, and file catalogs can expose internal activities and aid follow-on targeting while the primary objective remains data capture at scale.
EXF-0007 Compromised Ground System The adversary resides in mission ground infrastructure and uses its trusted position to siphon data at scale. With access to operator workstations, mission control servers, baseband/modem chains, telemetry processing pipelines, or archive databases, the attacker can mirror real-time streams, scrape recorder playbacks, export payload products, and harvest procedure logs and command histories. Because exfiltration rides normal paths, file staging areas, data distribution services, cloud relays, or cross-site links, it blends with routine dissemination. Compromise of scheduling tools and pass plans also lets the actor time captures to high-value downlinks and automate bulk extraction without touching the spacecraft.
EXF-0008 Compromised Developer Site By breaching development or integration environments (at the mission owner, contractor, or partner), the adversary gains access to source code, test vectors, telemetry captures, build artifacts, documentation, and configuration data, material that is often more complete than flight archives. Beyond theft of intellectual property, the attacker can embed telemetry taps, extended logging, or data “export” features into test harnesses, simulators, or flight builds so that, once fielded, the system produces extra observables or forwards content to non-mission endpoints. This activity typically occurs pre-launch during software production and ATLO, positioning exfiltration mechanisms to activate later in flight.
EXF-0009 Compromised Partner Site The adversary leverages third-party infrastructure connected to the mission, commercial ground stations, relay networks, operations service providers, data processing partners, to capture or relay mission data outside official channels. From these footholds, the attacker can mirror TT&C and payload feeds, scrape shared repositories, and man-in-the-middle cross-organization links (e.g., between partner stations and the primary MOC). Because partner environments vary in segmentation and monitoring, exfiltration can affect multiple missions or operators simultaneously, with stolen data exiting through the partner’s routine distribution mechanisms.