What evidence do auditors commonly ask for on 1.5 Use a Passive Asset Discovery Tool?

Passive discovery sensor deployment map against network segments; Weekly reports of newly observed devices; Register change records sourced from passive sensor findings.

What is the most common gap auditors find on 1.5?

Sensors placed on core segments only, missing branch or OT networks

CIS Controls v8.1 · CIS Control 1: Inventory and Control of Enterprise Assets

`1.5` Use a Passive Asset Discovery Tool

Add passive discovery, which listens to network traffic to spot connected devices, and use its findings to bring the asset register up to date weekly or more often. Implementation Group: IG3 only (for enterprises facing sophisticated attackers or holding highly sensitive data). Asset type: Devices. Security function: Detect.

Source: CIS Controls v8.1, 1.5. The statement above is our statement of the clause, read from the published text and cited so you can check it against the official text, not the instrument verbatim. Open CIS Controls v8.1 in the compliance library.

Scope: Implementation Groups: IG3. Security function: Detect; asset type: Devices.

Each safeguard shows its Implementation Groups. IG1 is the essential baseline for every enterprise, IG2 adds to it, IG3 is all 153. Version 8.1 adds the Govern security function and asks for more processes to be documented; numbering is unchanged from v8.

artefacts

held by a system

at each review

hard

to go live

Policy repository / GRC workspace

where the evidence lives

teal = a system already holds it · olive = produced at each review. To go live: easy when half or more of the artefacts are already held by a system, moderate from a quarter to a half, hard below a quarter.

These are the artefacts auditors commonly ask for on this requirement, our guidance rather than text from the standard. Your assessor decides what is sufficient in your context, and asks for samples across the period when a report covers one.

system holds itEvidence a system already holds

none for this control

periodic reviewEvidence produced at each review

Weekly reports of newly observed devices · Endpoint management (MDM / EDR)

governing documentDocuments that govern the control

Passive discovery sensor deployment map against network segments · Policy repository / GRC workspace
Register change records sourced from passive sensor findings · Policy repository / GRC workspace

First move

No system holds this evidence for you: it is people and documents. Reminders and routing to the owner still save time. Put the document under version control with an owner and review date, and log each review as a record with reviewer and date.

Common gaps auditors find

Sensors placed on core segments only, missing branch or OT networks
Findings reviewed irregularly
Passive output duplicated rather than merged with active discovery

Do this for your whole sheet

Paste the rows you run your controls from and get this mapping for every control at once, with the periodic-review ones flagged and a first move per row. No account for the first run.

Build my evidence sheet

1.4 Use Dynamic Host Configuration Protocol (DHCP) Logging to Update Enterprise Asset Inventory · 2.1 Establish and Maintain a Software Inventory