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Access Control

Modeling Access Control

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Adam Doupé

Arizona State University

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https://pwn.college

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Modeling Access Control

  • Subjects S
    • Things in the system that can act
  • Objects O
    • Assets or objects in the system (acted upon)
  • Rights R
    • What can the subject do to the object?

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Access Matrix Model

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F

G

U

V

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​

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U

r1, r2

r2

r4

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V

r2, r3

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r5, r6

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Simplified UNIX Model

  • Subjects are processes
    • p, q
  • Files are objects
    • f, g
  • Rights (read, write, execute, append, own)
    • r, w, x, a, o

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Access Control Matrix Model

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f

g

p

q

p

rwo

r

rwxo

w

q

a

ro

r

rwxo

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Access Control Matrix

  • Benefits
  • Drawbacks

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