CISAW Security Operations (OM) cheat sheet

CIA triad plus authenticity, non-repudiation and accountability define what is protected.

Risk combines threat, vulnerability and business impact; a vulnerability alone is not a risk.

Bell-LaPadula: no read up, no write down - confidentiality.

Biba: no read down, no write up - integrity.

Governance decides acceptable risk and accountability; management decides how to achieve it

Risk appetite (board-approved) differs from tolerance (variation) and capacity (maximum bearable)

Three Lines Model: internal audit must remain independent of control ownership

Identification, authentication, authorisation and accounting are four distinct steps.

MFA needs two different factor categories, not two instances of one.

RBAC suits stable job roles; ABAC suits context-dependent, fine-grained rules.

Kerberos uses a KDC with TGT and service tickets for SSO.

Symmetric ciphers handle bulk data; asymmetric ciphers solve key distribution and signatures.

Signing uses a specified signature scheme with the signer’s private key; verification and custody are essential to origin evidence.

ECB leaks patterns; use authenticated modes such as GCM or encrypt-then-MAC.

Internet-facing services belong in a DMZ; data stores sit in a filtered internal zone.

VLANs alone are not a trust boundary - add DAI, private VLANs and 802.1 X.

IPsec AH gives integrity only; ESP adds confidentiality.

IDS is passive and alerts; IPS is inline and blocks.

NAT is not a security control and temporary rules must be removed.

Harden from a documented baseline image: minimal services, default-deny host firewall, secure boot.

With conventional requested modes 0666/0777, umask 027 yields 0640 files and 0750 directories.

SUID/SGID binaries must be inventoried as escalation paths; avoid shared root.

EDR adds behaviour detection and response beyond signature antivirus.

Third-party applications are as important to patch as the operating system.

OWASP Top 10 is the standard vocabulary for application weaknesses.

Parameterised queries prevent SQL injection; output encoding prevents XSS.

Authorisation must be checked server-side on every request.

XSS executes script in the victim's browser; CSRF abuses the victim's session.

Classify data first, then apply encryption, masking, DLP and disposal rules by class.

Asset inventory and configuration baselines underpin every operational control.

Changes need an appropriate authorization path, recovery planning and relevant evidence.

Emergency changes still require retrospective documentation within a defined window.

Monitor log sources for silence, not just for events.

Distinguish historical Revision 2 phases from current NIST incident-response guidance integrated with broader risk management.

Containment precedes eradication in almost every scenario.

Capture volatile evidence (memory, connections) before disk and before power-off.

Validate findings and prioritize with exposure and business impact.

CVSS severity is not a complete organizational risk score.

Assessments and testing require appropriate authorization and scope.

Verify remediation and review documented exceptions.

Risk assessment cycles through identification, analysis, and evaluation, producing a maintained risk register

Single loss expectancy = asset value x exposure factor; annualized loss expectancy = SLE x annualized rate of occurrence

Risk requires a threat, a vulnerability, and an impact; none alone is sufficient

Inherent risk is before controls, residual risk after them - always state which is being scored

Control effectiveness and uncertainty affect any expected-loss comparison.

Distinguish tolerated data loss from tolerated interruption.

A recovery point and restore time must both meet the stated targets.

A same-failure-domain snapshot alone does not cover loss of that domain.

Verify complete restore procedures and actual dependency behavior.