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SI-4(18) SI · System and Information Integrity

Analyze Traffic and Covert Exfiltration

LOW MODERATE HIGH
1 Overlay 0 Related Controls
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Requirements NIST SOURCE

Analyze outbound communications traffic at external interfaces to the system and at the following interior points to detect covert exfiltration of information: [interior points].

Discussion (NIST Supplemental Guidance)

Organization-defined interior points include subnetworks and subsystems. Covert means that can be used to exfiltrate information include steganography.

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-4(18) 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

  1. interior points within the system where communications traffic is to be analyzed are defined;
  2. outbound communications traffic is analyzed at interfaces external to the system to detect covert exfiltration of information;
  3. outbound communications traffic is analyzed at <SI-04(18)_ODP interior points> to detect covert exfiltration of information.

Examine

[SELECT FROM: System and information integrity policy; system and information integrity procedures; procedures addressing system monitoring tools and techniques; system design documentation; network diagram; system monitoring tools and techniques documentation; system configuration settings and associated documentation; system monitoring logs or records; system audit records; system security plan; other relevant documents or records].

Interview

[SELECT FROM: System/network administrators; organizational personnel with information security responsibilities; organizational personnel installing, configuring, and/or maintaining the system; organizational personnel responsible for monitoring the system; organizational personnel responsible for the intrusion detection system].

Test

[SELECT FROM: Organizational processes for intrusion detection and system monitoring; mechanisms supporting and/or implementing intrusion detection and system monitoring capabilities; mechanisms supporting and/or implementing an analysis of outbound communications traffic].

Overlays

Showing the OT/ICS overlay for the parent control SI-4 — see the SI-4(18) 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

  • Base control: Included (matches standard baseline)

MODERATE

  • Base control: Included (matches standard baseline)
  • Included: (2) (4) (5)

HIGH

  • Base control: Included (matches standard baseline)
  • Included: (2) (4) (5) (10) (12) (14) (20) (22)

STIGs & CCIs

No STIG checks or CCI mappings are currently loaded for SI-4(18). 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 intrusion detection and system monitoring
  • mechanisms supporting and/or implementing intrusion detection and system monitoring capabilities
  • mechanisms supporting and/or implementing an analysis of outbound communications traffic

Other Records

  • system and information integrity procedures
  • procedures addressing system monitoring tools and techniques
  • network diagram
  • system monitoring tools and techniques documentation
  • system monitoring logs or records
  • system audit records
  • other relevant documents or records