safemode.space
← All techniques
EX-0012.05
ST0004Execution
sub-technique

Scheduling Algorithm

Parent: EX-0012

Description

Spacecraft typically rely on real-time scheduling, fixed-priority or deadline/periodic schemes, driven by timers, tick sources, and per-task parameters. Threat actors target these parameters and associated tables to skew execution order and timing. Edits may change priorities, periods, or deadlines; adjust CPU budgets and watchdog thresholds; alter ready-queue disciplines; or reconfigure timer tick rates and clock sources. They may also modify task affinities, message-queue depths, and interrupt masks so preemption and latency characteristics shift. Small changes can have large effects: high-rate control loops see added jitter, estimator updates miss deadlines, command/telemetry handling starves, or low-priority maintenance tasks monopolize cores due to mis-set periods. Manipulated schedules can create intermittent, state-dependent malfunctions that are hard to distinguish from environmental load. The essence of the technique is to weaponize time, reshaping when work happens so that otherwise correct code produces unsafe or exploitable behavior.

Mappings

EU regulation articles

  • craAnnex I, Part I, (2)(d)
    addresses
    moderate
    derived

    Authentication obligations bound who can alter scheduling parameters whose modification can starve safety-critical tasks.

  • craAnnex I, Part I, (2)(f)
    addresses
    high
    derived

    Integrity protection covers scheduling-algorithm parameters and per-task configuration; modifications must be detected and rejected.

  • eu-space-actArt. 81(3)
    addresses
    high
    direct

    Real-time scheduling parameters (priorities, periods, deadlines, watchdog thresholds) are critical-function configuration — 81(3)(b)'s access restriction governs which entities can edit these.

  • nis2Art. 21(2)(i)
    addresses
    moderate
    direct

    Scheduler parameters (priorities, periods, deadlines, CPU budgets, watchdog thresholds, tick rates) are access-controlled real-time configuration; Art. 21(2)(i)'s access-control + asset-management obligation governs which roles can edit them.

  • nis2-implAnnex 6.3.1
    addresses
    moderate
    derived

    Configuration-management obligations cover task-scheduling configuration as part of the documented baseline whose deviations must be detected and reviewed.

  • nis2-implAnnex 6.4.1
    addresses
    moderate
    derived

    Scheduling-algorithm parameters (priorities, periods, deadlines) are change-managed configuration; modifications must follow documented procedures with review and rollback paths.

ENISA controls

  • ENISA-STL-2025-03-sD.21-i01
    addresses
    high

    Schedules and timeline configurations fall under documented configuration baselines whose unauthorised modification triggers review.

  • ENISA-STL-2025-03-sD.21-i08
    addresses
    moderate

    Change management governs documented modification procedures for scheduling tables and priorities, relevant to the parameters EX-0012.05 edits.

Cross-reference controls

SPARTA countermeasures

Cite as SafeMode Space, EX-0012.05 (SPARTA v3.2).

Built 2026-07-25 from 216 techniques, 334 regulation articles, 125 ENISA controls, 2,610 framework controls, and 90 countermeasures.