February 12, 2024 Outline

Reading: text, §7.4, 8.1
Due: Extra Credit #C, due February 14; Project Progress Report, due February 16; Homework #3 due February 21

Module 27 (Reading: text, §7.4)

1. Countermeasures
   1. Manipulate opening of connection
   2. Control which packets get through, or the rate at which they get through

2. Amplification attacks

Module 28 (Reading: text, §8.1)

6. Brewer-Nash (Chinese Wall) Policy
   1. Low-level entities are objects; all objects concerning the same corporation form a CD (company dataset); CDs whose corporations are in competition are grouped into COIs (Conflict of Interest classes)
   2. Intuitive goal: keep one subject from reading different CDs in the same COI, or reading one CD and writing to another in same COI
   3. Simple Security Property: Read access granted if the object:
      1. is in the same CD as an object already accessed by the subject; or
      2. is in a CD in an entirely different COI
   4. Theorems:
      1. Once a subject has accessed an object, only other objects in that CD are available within that COI;
      2. Subject has access to at most 1 dataset in each COI class
   5. Exceptions: sanitized information
   6. *-Property: Write access is permitted only if:
      1. Read access is permitted by the simple security property; and
      2. No object in a different CD in that COI can be read, unless it contains sanitized information
   7. Key result: information can only flow within a CD or from sanitized information
   8. Aggressive Chinese Wall model
   9. Comparison to BLP
   10. Comparison to Clark-Wilson

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ECS 235B, Foundations of Computer and Information Security Version of February 12, 2024 at 7;15M

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