Using AttributeBased Access Control to Enable AttributeBased Messaging

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Using Attribute-Based Access Control to Enable
Attribute-Based Messaging
Rakesh Bobba, Omid Fatemieh, Fariba Khan, Carl A.
Gunter and Himanshu Khurana University of
Illinois at Urbana-Champaign
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Introduction to ABM

• Attribute-Based Messaging (ABM) Targeting
  messages based on attributes.

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Introduction to ABM

• Attribute-Based Messaging (ABM) Targeting
  messages based on attributes.

• Examples
• Address all faculty going on sabbatical next term
• Notify all female CS graduate students who passed
  qualifying exams of a scholarship opportunity

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Why ABM?

• Attribute-based systems have desirable properties
• flexibility, privacy and intuitiveness
• Attribute-Based Messaging (ABM) brings these
  advantages to e-mail messaging
• enhances confidentiality by supporting targeted
  messaging
• via dynamic and transient groups
• enhances relevance of messages
• by reducing unwanted messages

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Challenges

• Access Control
• access to such a system should be carefully
  controlled
• potential for spam
• privacy of attributes
• Deployability
• system should be compatible with existing
  infrastructure
• Efficiency
• system should have comparable performance to
  regular e-mail

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Enterprise Architecture

• Ensuing Issues
• ABM Address Format, Client I/F
• Access Control - policy specification and
  enforcement
• Attribute Database creation and maintenance

Attr. DB
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Enterprise Architecture cont.

• Attribute database
• all enterprises have attribute data about their
  users
• data spread over multiple, possibly disparate
  databases
• assume that this attribute data is available to
  ABM system
• information fabric , data services layer
• ABM address format
• logical expressions of attribute value pairs
• disjunctive normal form

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Access Control

• Access Control Lists (ACLs)
• difficult to manage

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Access Control

• Access Control Lists (ACLs)
• difficult to manage
• Role-Based Access Control (RBAC)
• simplified management if roles already exist

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Access Control

• Access Control Lists (ACLs)
• difficult to manage
• Role-Based Access Control (RBAC)
• simplified management if roles already exist
• Attribute-Based Access Control (ABAC)
• uses same attributes used to target messages
• more flexible policies than with RBAC
• Access policy
• XACML is used to specify access policies
• Suns XACML engine is used for policy decision

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Access Control cont.

• Problem
• need policy per logical expression
• policy explosion
• Solution?
• one policy per ltattribute,valuegt

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Deployability

• Use existing e-mail infrastructure (SMTP)
• address ABM messages to the ABM server (MUA) and
  add ABM address as a MIME attachment
• No modification to client
• use a web server to aid the sender in composing
  the ABM address via a thin client (web browser)
• E-mail like semantics
• policy specialization

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Putting It All Together
PDP Suns XACML Engine
Legend PS Policy Specialization MS
Messaging AR Address Resolution
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Security Analysis

• Problem
• open to replay attacks
• Solution
• MTA configured with SMTP authentication
• with additional message specific checks

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Experimental Setup

• Measured
• latency over regular e-mail
• with and without access control
• latency of Policy Specialization
• Setup
• up to 60K users
• 100 attributes in the system
• 20 of attributes common to most users
• 80 of attributes sparsely distributed

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Results
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Results Continued
Policy Specialization Latency
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Other Considerations

• Policy Administration
• one policy per ltattribute ,valuegt not per address
• further be reduced to one policy per attribute
• Privacy
• of sender and receivers
• of ABM address
• Usability
• user interfaces

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Related Work

• Technologies
• List Servers
• Customer Relationship Management (CRM)
• Secure role-based messaging
• WSEmail

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Future Work

• Inter-domain ABM
• e.g., address doctors in the tri-state area who
  have expertise in a specific kind of surgical
  procedure
• challenge attribute mapping
• application in emergency communications
• Encrypted ABM

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