Flashcards
Access Control
Cards in this deck (19)
- 1Define Principal, Subject and ObjectPrincipal: Represents a user e.g. User ID Subject: Active entity which performs operations on behalf of a principal
Object: A resource which can be accessed - 2What is the process of accessing a resource?Principal -> Operation -> Reference monitor -> Object
- 3What are the 2 steps to access control?Authentication: Who?
Authorisation: Do they have permission to access this object? - 4What 2 things can we focus access control on?Subject: What they can do
Objects: What can be done to an object - 5What are the 2 ownership policies?1. Discretionary: Owners of resources. They decide access control.
2. Mandatory: System-wide policies - 6Name the 3 access control structures1. Access Control Matrix
2. Access Control Lists
3. Capabilities - 7Explain Access Control MatriciesDefines the access rights for each subject/object pair.
Offers fine-grained control but isn't practical (memory requirement) - 8Explain Access Control ListsDefines access rights per object, stored alongside an object.
More efficient than ACMs.
Hard to manage / get an overview of subject permissions - 9Explain CapabilitiesDefines access rights per subject.
More efficient than ACMs.
Hard to manage / get an overview of object permissions. - 10What access control structure does UNIX use?Simplified ACLs: User/Group/Other instead of each subject.
Supports R/W/E permissions. - 11What access control structure does Windows use?ACLs.
Supports R/W/E permissions + Take ownership / Change permissions / Delete. Higher control, more complexity. - 12How can the complexity of access control structures be combatted?Intermediate Controls
- 13State 5 intermediate controls1. Groups
2. Negative Permissions
3. Role-based Access
4. Protection Rings
5. Partial Ordering - 14What are groups?Groups are collections of subjects.
Groups have access permissions. - 15What are negative permissions?Define operations subjects cannot perform
- 16What is Role-based Access Control?Roles define access rights.
Subjects perform a particular role.
Easier to scale.
Used for large networks / organisations - 17What's the difference between Groups and Roles?Groups = Collection of users.
Role = Collection of permissions - 18What are protection rings?Offer hardware-based access control. Subjects/objects given a importance number.
Access is granted by comparing importance. 0-3, Hardware-User process - 19What is partial ordering?Hierarchical access control.
Subsets of groups.
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- Bachelors Degree Computer Science (Computer Security) Flashcards on Access Control, created by Alex Neves on 23/05/2016.
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- Alex Neves
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