Page 249 - CISSO_Prep_ Guide

Security Models
• Bell-Lapadula: confidentiality model (read
down and write up).
• “state” machine model.
• Simple security property: subject
cannot read an object of higher
sensitivity.
• Star property (*): subject cannot
write lower
• Strong Star: cannot read/write to the
object of higher/lower .
• Does NOT address the "need to
know" of the user.
• Biba Integrity: integrity model (read up and
write down)
• Simple integrity: cannot read down.
• Integrity star * property: cannot write
higher.
• Invocation property: cannot invoke
execution up.
• 1st Goal of Integrity - Unauthorized
users make no changes.
• Access tuple: Subject and Object
• Clark & Wilson: integrity model
• Reaffirmed Biba's first goal of
integrity.
• Postulated the second goal of
integrity - "Authorized users make no
unauthorized changes."