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Out-of-band Authentication

LOW MODERATE HIGH
1 Overlay 3 Related Controls
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Requirements NIST SOURCE

Implement the following out-of-band authentication mechanisms under [conditions]: [out-of-band authentication].

Discussion (NIST Supplemental Guidance)

Out-of-band authentication refers to the use of two separate communication paths to identify and authenticate users or devices to an information system. The first path (i.e., the in-band path) is used to identify and authenticate users or devices and is generally the path through which information flows. The second path (i.e., the out-of-band path) is used to independently verify the authentication and/or requested action. For example, a user authenticates via a notebook computer to a remote server to which the user desires access and requests some action of the server via that communication path. Subsequently, the server contacts the user via the user’s cell phone to verify that the requested action originated from the user. The user may confirm the intended action to an individual on the telephone or provide an authentication code via the telephone. Out-of-band authentication can be used to mitigate actual or suspected "man-in the-middle" attacks. The conditions or criteria for activation include suspicious activities, new threat indicators, elevated threat levels, or the impact or classification level of information in requested transactions.

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 IA-2(13) 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. out-of-band authentication mechanisms to be implemented are defined;
  2. conditions under which out-of-band authentication is to be implemented are defined;
  3. <IA-02(13)_ODP[01] out-of-band authentication> mechanisms are implemented under <IA-02(13)_ODP[02] conditions>.

Examine

[SELECT FROM: Identification and authentication policy; system security plan; procedures addressing user identification and authentication; system design documentation; system configuration settings and associated documentation; system audit records; system-generated list of out-of-band authentication paths; other relevant documents or records].

Interview

[SELECT FROM: Organizational personnel with system operations responsibilities; organizational personnel with account management responsibilities; organizational personnel with information security responsibilities; system/network administrators; system developers].

Test

[SELECT FROM: Mechanisms supporting and/or implementing out-of-band authentication capability].

Overlays

Showing the OT/ICS overlay for the parent control IA-2 — see the IA-2(13) 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)
  • Included: (1) (2) (8) (12)

MODERATE

  • Base control: Included (matches standard baseline)
  • Included: (1) (2) (8) (12)

HIGH

  • Base control: Included (matches standard baseline)
  • Included: (1) (2) (5) (8) (12)

STIGs & CCIs

No STIG checks or CCI mappings are currently loaded for IA-2(13). 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

  • Identification and authentication policy
  • system security plan

Configuration

  • system design documentation
  • system configuration settings and associated documentation

Testing

  • Mechanisms supporting and/or implementing out-of-band authentication capability

Other Records

  • procedures addressing user identification and authentication
  • system audit records
  • system-generated list of out-of-band authentication paths
  • other relevant documents or records