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Ashish Kamra , Elisa Bertino Purdue University Presenter: Ashish Kundu. PRIVILEGE STATES BASED ACCESS CONTROL FOR FINE GRAINED INTRUSION RESPONSE. The Real Authors . akamra@purdue.edu . bertino@cs.purdue.edu. Motivation. Databases Anomaly Detection Anomaly Response Access Control .
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Ashish Kamra, Elisa Bertino Purdue University Presenter: AshishKundu PRIVILEGE STATES BASED ACCESS CONTROL FOR FINE GRAINEDINTRUSION RESPONSE
The Real Authors akamra@purdue.edu bertino@cs.purdue.edu
Motivation • Databases • Anomaly Detection • Anomaly Response • Access Control
Access Control Decision Semantics Allow Deny Request Reference Monitor
Extended Decision Semantics Allow Deny Request Reference Monitor Taint Suspend
Primary Contribution Mechanism to enhance the decision semantics of an access control implementation
Support for fine-grained intrusion response Detection engine Response engine Drop Request Request Anomaly Log Request Passive Monitoring 2nd factor of authentication
Mapping Taint decision semantic Passive Monitoring 2nd factor of authentication Suspend decision semantics
Privilege States - glue for the mapping • Assign states to privileges • Response system changes privilege state • fine-grained response actions • Response : access control decision semantics
Privilege States • “state” to every privilege • a user or role • Five privilege states
Privilege State Semantics • “DENY”: negative authorizations • “SUSPEND”: request suspension • “TAINT”: request tainting • “GRANT”: standard SQL GRANT • “UNASSIGN”: standard SQL REVOKE
Example • U1 is a member of role R1 • DBA assigns • SELECT privilege in DENY on T1 to user U1 • SELECT privilege in TAINT on T1 to role R1 • Privilege state of SELECT on T1 for U1 ???
Privilege State Dominance DENY SUSPEND X means ‘X’ overrides ‘Y’ TAINT Y GRANT UNASSIGN
Privilege State Transitions unassign + + grant deny GRANT REVOKE ? suspend ? ? + taint / / / / ? + ? + DENY TAINT + / / SUSPEND ?
Formal model For details, please refer to the paper …
Considering Role Hierarchies • Role hierarchy based on privilege inheritance • What about privileges in “deny”, “suspend” and “taint” states? R_parent {insert} {select} R_child {select}
Privilege Orientation Modes up unassign, grant down deny, taint, suspend neutral
Privilege Propagation R8 R5 {select,grant} R6 R7 {insert,deny,down} R2 R3 R4 {select,grant} {insert,deny,down} R1 Recursive Propagation
Implementation in PostgreSQL • New SQL commands • TAINT, SUSPEND • Enhanced Access Control Lists • To support privilege states and orientation modes • Re-authentication procedure for a privilege in “suspend” state
Conclusions • Fine-granular access control in databases • Anomaly response mechanisms • Facilitates policy development • Formal model and experimental evaluation