# SI-4(4) — Inbound and Outbound Communications Traffic

- **Control ID:** SI-4(4)
- **Family:** [SI](/md/families/SI.md)
- **Baselines:** moderate, high
- **Enhancement of:** [SI-4](/md/controls/SI-4.md)

## Description

Determine criteria for unusual or unauthorized activities or conditions for inbound and outbound communications traffic; Monitor inbound and outbound communications traffic \[assignment\] for \[assignment\].

## Discussion

Unusual or unauthorized activities or conditions related to system inbound and outbound communications traffic includes internal traffic that indicates the presence of malicious code or unauthorized use of legitimate code or credentials within organizational systems or propagating among system components, signaling to external systems, and the unauthorized exporting of information. Evidence of malicious code or unauthorized use of legitimate code or credentials is used to identify potentially compromised systems or system components.

## Implementation guidance

No content available.

## CSF 2.0 subcategories

No content available.

## Related controls

No content available.

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Derived from official NIST publications (NIST SP 800-53 Rev 5 and NIST CSF 2.0). nistcontrols.com is not affiliated with NIST.