SI-5 asks you to receive security alerts, advisories and directives from sources you define on an ongoing basis, generate internal ones when needed, disseminate them to the right people, and implement directives within set time frames or tell the issuer where you fall short. NIST 800-53 binds US federal systems and, by contract, some others. The idea carries over to any company that has to react to published vulnerabilities.
What it means in practice
The guidance points to CISA, which produces alerts and advisories, and to directives issued by OMB or other authorities. Federal agencies must meet directive deadlines. A private company is rarely under a directive, but customers and contracts often expect you to track the same sources.
Four verbs matter: receive, generate, disseminate, implement. Missing any one is a gap.
The one enhancement is automated alerts and advisories (SI-5.1).
Evidence to collect
- The list of sources you subscribe to, with the mailbox or feed that receives them.
- A distribution list showing who gets which alerts.
- Tickets showing a real advisory was triaged, with dates.
- Internal advisories you issued.
- For any advisory not met in time, a record of the exception.
Common gaps
- Subscriptions that go to one person who left.
- Alerts received but never linked to a ticket.
- No defined timeframe, so nothing is late.
- Advisories read only for infrastructure, not for application dependencies.
How to implement it
Pick sources for your stack: vendor security notices, CISA advisories and the feeds for your language ecosystems. Route them into one channel or ticket queue, assign an owner for the week, and set response targets by severity.
Quick check
Do I need to be a federal agency to follow SI-5?
No. The directive language is federal, but receiving and acting on advisories is a sensible practice for any company and a common customer question.
