Unexpected Access to Cryptographic Keys

Detection of unauthorized access to cryptographic keys used for decryption, suggesting that a threat actor may be attempting to disable or bypass the spacecraft's encryption mechanisms.

STIX Pattern

[x-opencti-cryptographic-key:access_time != 'authorized_access_time' AND x-opencti-cryptographic-key:usage = 'decryption']

SPARTA TTPs

ID Name Description
REC-0001.03 Cryptographic Algorithms Adversaries look for the complete crypto picture: algorithms and modes, key types and lifecycles, authentication schemes, counter or time-tag handling, anti-replay windows, link-layer protections, and any differences between uplink and downlink policy. With algorithm and key details, a threat actor can craft valid telecommands, masquerade as a trusted endpoint, or degrade availability through replay and desynchronization. Sources include interface specifications, ground software logs, test vectors, configuration files, contractor laptops, and payload-specific ICDs that reuse bus-level credentials. Particular risk arises when command links rely on authentication without confidentiality; once an adversary acquires the necessary keys or counters, they can issue legitimate-looking commands outside official channels. Programs should assume that partial disclosures, MAC length, counter reset rules, or key rotation cadence, aid exploitation.
RD-0003.02 Cryptographic Keys Adversaries seek any cryptographic material that confers command or decryption authority: uplink authentication/MAC keys and counters, link-encryption/session keys and KEKs, loading/transfer keys for HSMs, PN/spreading codes, modem credentials, and station or crosslink keys. Acquisition routes include compromised ground systems and laptops, misconfigured repositories and ticket systems, memory/core dumps, training datasets and screenshots, contractor support channels, and poorly controlled key-loading or recovery procedures. Because some missions authenticate uplink without encrypting it, possession of the right keys/counters may be sufficient to inject accepted commands outside official channels or to desynchronize anti-replay.
PER-0004 Replace Cryptographic Keys The adversary cements control by changing the cryptographic material the spacecraft uses to authenticate or protect links and updates. Targets include uplink authentication keys and counters, link-encryption/session keys and key-encryption keys (KEKs), key identifiers/selectors, and algorithm profiles. Using authorized rekey commands or key-loading procedures, often designed for over-the-air use, the attacker installs new values in non-volatile storage and updates selectors so subsequent traffic must use the attacker’s keys to be accepted. Variants desynchronize anti-replay by advancing counters or switching epochs, or strand operators by flipping profiles to a mode for which only the adversary holds parameters. Once replaced, the new material persists across resets and mode changes, turning the spacecraft into a node that recognizes the adversary’s channel while rejecting former controllers.
PER-0005 Credentialed Persistence Threat actors may acquire or leverage valid credentials to maintain persistent access to a spacecraft or its supporting command and control (C2) systems. These credentials may include system service accounts, user accounts, maintenance access credentials, cryptographic keys, or other authentication mechanisms that enable continued entry without triggering access alarms. By operating with legitimate credentials, adversaries can sustain access over extended periods, evade detection, and facilitate follow-on tactics such as command execution, data exfiltration, or lateral movement. Credentialed persistence is particularly effective in environments lacking strong credential lifecycle management, segmentation, or monitoring allowing threat actors to exploit trusted pathways while remaining embedded in mission operations.
DE-0003.07 Cryptographic Modes Many missions separate authentication from confidentiality and allow on-orbit selection of algorithms, keys, profiles, or “crypto off/clear” states. Adversaries manipulate these mode controls and selectors to desynchronize ground and space or to hide content: flipping to a profile that the ground is not using, requesting clear telemetry while maintaining authenticated uplink, or rotating key IDs so frames validate internally but appear undecodable to external tools. Mode indicators and status words can also be biased so ground displays show expected settings while the link actually operates under attacker-chosen parameters, masking command and data exchanges within normal-looking traffic.
EXF-0010 Payload Communication Channel Many payloads maintain communications separate from the primary TT&C, direct downlinks to user terminals, customer networks, or experimenter VPNs. An adversary who implants code in the payload (or controls its gateway) can route host-bus data into these channels, embed content within payload products (e.g., steganographic fields in imagery/telemetry), or schedule covert file transfers alongside legitimate deliveries. Because these paths are expected to carry high-rate mission data and may bypass TT&C monitoring, they provide a discreet conduit to exfiltrate payload or broader spacecraft information without altering the primary command link’s profile.