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CompTIA Security+ 3.2 ISC2 CISSP 3.1
TechKnowSurge Catalog Interactives Fail Open or Fail Closed?
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Fail Open or Fail Closed?

When this control breaks, should the gate open or turn into a wall? Weigh confidentiality and integrity against availability.

⚑ Complete this interactive to capture a CTF flag worth 5 points.

About this interactive

Whatever you put in place will fail at some point, so plan the failure. Fail open means the control gets out of the way when it breaks. In the lesson's picture, the gate in the wall disappears: the asset stays available, but anyone can reach it. Fail closed, or fail secure, means the control falls back to a secure state. The gate turns into wall: nothing gets through, so the asset is protected but unavailable. To decide, weigh the CIA triad. On one side, how bad would it be if confidentiality or integrity were lost while the control is down? On the other, how critical is it that the thing stays available? High confidentiality or integrity risk points to fail closed. Low confidentiality and integrity risk with a real need for availability points to fail open. One case overrides the scale: people's safety. A badge lock on a door people need to leave by during a fire fails open, so nobody is trapped inside. The lesson's scenarios: the firewall fails closed, since an open firewall exposes the whole network; a staff web filter fails open, since losing it costs a little productivity while losing the internet stops work; access control on a sensitive folder fails closed; access control on a printer fails open.

What you'll learn

Aligned to

CompTIA Security+
3.2 Given a scenario, apply security principles to secure enterprise infrastructure.
ISC2 CISSP
3.1 Research, implement, and manage engineering processes using secure design principles

Key terms

Fail Open
A failure state in which a security control defaults to allowing access or traffic when it malfunctions, prioritizing availability over confidentiality and integrity.
Fail Closed
A failure state in which a security control defaults to denying access or traffic when it malfunctions, prioritizing confidentiality and integrity over availability.
CIA Triad
The three core principles of information security: Confidentiality, Integrity, and Availability.
Availability
The assurance that systems and data are accessible and operational when needed by authorized users.
Confidentiality
The principle that information is accessible only to those authorized to access it.

Topics

Fail Open Fail Closed Cia Triad Security Control Interactive Categorize

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