Timing Interactions

LOW MODERATE HIGH

1 Overlay 0 Related Controls

Requirements NIST SOURCE

Account for timing interactions among system components in determining appropriate responses for invalid inputs.

Discussion (NIST Supplemental Guidance)

In addressing invalid system inputs received across protocol interfaces, timing interactions become relevant, where one protocol needs to consider the impact of the error response on other protocols in the protocol stack. For example, 802.11 standard wireless network protocols do not interact well with Transmission Control Protocols (TCP) when packets are dropped (which could be due to invalid packet input). TCP assumes packet losses are due to congestion, while packets lost over 802.11 links are typically dropped due to noise or collisions on the link. If TCP makes a congestion response, it takes the wrong action in response to a collision event. Adversaries may be able to use what appear to be acceptable individual behaviors of the protocols in concert to achieve adverse effects through suitable construction of invalid input. The invalid inputs are those related to the information inputs defined by the organization in the base control ( SI-10).

Implementation Guidance

Engineering Interpretation

Original engineering commentary written for this explorer — not NIST source text and not authoritative guidance.

No engineering interpretation has been authored for SI-10(4) yet. This section is architected to receive it — see the Requirements and Assessment sections above for the authoritative NIST source content in the meantime.

Assessment

NIST SP 800-53A REV 5.2.0

Assessment Objectives

timing interactions among system components are accounted for in determining appropriate responses for invalid inputs.

Examine

[SELECT FROM: System and information integrity policy; system and information integrity procedures; procedures addressing information input validation; system design documentation; system configuration settings and associated documentation; system audit records; system security plan; other relevant documents or records].

Interview

[SELECT FROM: Organizational personnel responsible for information input validation; organizational personnel with information security responsibilities; system/network administrators; system developer].

Test

[SELECT FROM: Organizational processes for determining appropriate responses to invalid inputs; automated mechanisms supporting and/or implementing responses to invalid inputs].

Overlays

Showing the OT/ICS overlay for the parent control SI-10 — see the SI-10(4) entries within each baseline below.

OT/ICS Overlay SP 800-82r3

NIST SP 800-82r3 Appendix F, Table 22. Blank baseline means the control/control enhancement is not selected in that initial OT baseline.

LOW

Not applicable at this tier.

MODERATE

Base control: Included (matches standard baseline)

HIGH

Base control: Included (matches standard baseline)

STIGs & CCIs

No STIG checks or CCI mappings are currently loaded for SI-10(4). This section is architected to display, per product: STIG ID, Finding ID, Severity, Title, Description, Check, Fix, CCI, and NIST control mapping — but nothing is populated here until a real DISA STIG/CCI dataset is ingested.

Learn more about STIG/CCI integration →

Evidence

Potential Evidence — Derived

Categorized from the SP 800-53A "Examine"/"Test" artifact list above by keyword — not an authoritative NIST evidence list.

Policy

System and information integrity policy
system security plan

Configuration

system design documentation
system configuration settings and associated documentation

Testing

Organizational processes for determining appropriate responses to invalid inputs
automated mechanisms supporting and/or implementing responses to invalid inputs

Other Records

system and information integrity procedures
procedures addressing information input validation
system audit records
other relevant documents or records