Data and Applications Security Developments and Directions Dr. Bhavani Thuraisingham The University of Texas at Dallas Policies June 2011

Outline of the Unit l Need to Know to Need to Share l RBAC l UCON l ABAC l Release and Dissemination Control l Risk based access control l Trust Management/Credential/Disclosure l Directions l Major conferences for Policy and Access Control: - IEEE Policy Workshop - ACM SACMAT

References l Useful papers - RBAC: Ravi S. Sandhu, Edward J. Coyne, Hal L. Feinstein, Charles E. Youman: Role-Based Access Control Models. IEEE Computer 29(2): (1996)Edward J. CoyneHal L. Feinstein Charles E. Youman IEEE Computer 29 - UCON: Jaehong Park, Ravi S. Sandhu: The UCONABC usage control model. ACM Trans. Inf. Syst. Secur. 7(1): (2004) (read about 20 pages)Ravi S. SandhuACM Trans. Inf. Syst. Secur. 7 - DCON: Roshan K. Thomas, Ravi S. Sandhu: Towards a Multi-dimensional Characterization of Dissemination Control. POLICY 2004: (IEEE)Ravi S. SandhuPOLICY 2004

Need to Know to Need to Share l Need to know policies during the cold war; even if the user has access, does the user have a need to know? l Pose 9/11 the emphasis is on need to share - User may not have access, but needs the data l Do we give the data to the user and then analyze the consequences l Do we analyze the consequences and then determine the actions to take l Do we simply not give the data to the user l What are risks involved?

RBAC l Access to information sources including structured and unstructured data both within the organization and external to the organization l Access based on roles l Hierarchy of roles: handling conflicts l Controlled dissemination and sharing of the data

RBAC (Sandhu)

UCON l RBAC model is incorporated into UCON and useful for various applications - Authorization component l Obligations - Obligations are actions required to be performed before an access is permitted - Obligations can be used to determine whether an expensive knowledge search is required l Attribute Mutability - Used to control the scope of the knowledge search l Condition - Can be used for resource usage policies to be relaxed or tightened

UCON (Sandhu)

ABAC: Attribute based access control l Users have credentials l Users are granted access to resources based on their credentials l Credentials are also called attributes

Dissemination Policies l Release policies will determine to whom to release the data - What is the connection to access control - Is access control sufficient - Once the data is retrieved from the information source (e.g., database) should it be released to the user l Once the data is released, dissemination policies will determine who the data can be given to - Electronic music, etc.

Risk Based Data Sharing/Access Control l What are the risks involved in releasing/disseminating the data l Risk modeling should be integrated with the access control model l Simple method: assign risk values l Higher the risk, lower the sharing l What is the cost of releasing the data? l Cost/Risk/Security closely related

Trust Management l Trust Services - Identify services, authorization services, reputation services l Trust negotiation (TN) - Digital credentials, Disclosure policies l TN Requirements - Language requirements l Semantics, constraints, policies - System requirements l Credential ownership, validity, alternative negotiation strategies, privacy l Example TN systems - KeyNote and Trust-X (U of Milan), TrustBuilder (UIUC)

Trust Management

The problem: establishing trust in open systems l Mutual authentication - Assumption on the counterpart honesty no longer holds - Both participants need to authenticate each other  Interactions between strangers - In conventional systems user identity is known in advance and can be used for performing access control - In open systems partecipants may have no pre-existing relationship and may not share a common security domain

Trust Negotiation model l A promising approach for open systems where most of the interactions occur between strangers l The goal : establish trust between parties in order to exchange sensitive information and services l The approach : establish trust by verifying properties of the other party

Trust negotiation: the approach Interactions between strangers in open systems are different from traditional access control models Policies and mechanisms developed in conventional systems need to be revised USER ID’s VS. SUBJECT PROPERTIES ACCESS CONTROL POLICIES VS. DISCLOSURE POLICIES

Subject properties: digital credentials l Assertion about the credential owner issued and certified by a Certification Authority. CA  Each entity has an associated set of credentials, describing properties and attributes of the owner.

Use of Credentials Credential Issuer Digital Credentials -Julie -3 kids -Married -American Company A Company B Want to know citizenship Want to know marital status -Julie - American -Julie - Married Alice Check Referenced from

Credentials l Credentials can be expressed through the Security Assertion Mark-up Language (SAML) l SAML allows a party to express security statements about a given subject - Authentication statements - Attribute statements - Authorization decision statements

Disclosure policies l Disclosure policies govern: Access to protected resources Access to sensitive information Disclosure of sensitive credentials l Disclosure policies express trust requirements by means of credential combinations that must be disclosed to obtain authorization Disclosure policies

Disclosure policies - Example l Suppose NBG Bank offers loans to students l To check the eligibility of the requester, the Bank asks the student to present the following credentials - The student card - The ID card - Social Security Card - Financial information – either a copy of the Federal Income Tax Return or a bank statement

Disclosure policies - Example p1= ({}, Student_Loan  Student_Card()); p2= ({p1}), Student_Loan  Social_Security_Card()); p3= ({p2}, Student_Loan  Federal_Income_Tax_Return()); p4= ({p2}, Student_Loan  Bank_Statement()); P5=({p3,p4}, Student_Loan  DELIV); These policies result in two distinct “policy chains” that lead to disclosure [p1, p2, p3, p5][p1, p2, p4, p5]

Trust Negotiation - definition The gradual disclosure of credentials and requests for credentials between two strangers, with the goal of establishing sufficient trust so that the parties can exchange sensitive information and/or resources

Trust- X system: Joint Research with University of Milan l A comprehensive XML based framework for trust negotiations:  Trust negotiation language ( X -TNL)  System architecture  Algorithms and strategies to carry out the negotiation process

Trust- X language : X -TNL  Able to handle mutliple and heterogeneus certificate specifications:  Credentials  Declarations  Able to help the user in customizing the management of his/her own certificates  X -Profile  Data Set  Able to define a wide range of protection requirements by means of disclosure policies

X -TNL: Credential type system X -TNL simplifies the task of credential specification by using a set of templates called credential types Uniqueness is ensured by use of XML Namespaces Credential types are defined by using Document Type Definition <!DOCTYPE library_badge[ <!ELEMENT library_badge (name, address, phone_number*, ?, release_date, profession,Issuer)> <!ATTLIST Issuer XML:LINK CDATA #FIXED “SIMPLE” HREF CDATA #REQUIRED TITLECDATA #IMPLIED> ]>

Trust- X negotiation phases- basic model 1. Introduction  Send a request for a resource/service  Introductory policy exchanges 2. Policy evaluation phase  Disclosure policy exchange  Evaluation of the exchanged policies in order to determine secure solutions for both the parties. 3. Certificate exchange phase  Exchange of the sequence of certificates determined at step n. 2.

Trust- X Architecture Trust- X has been specifically designed for a peer-to-peer environment in that each party is equipped with the same functional modules and thus it can alternatively act as a requester or resource controller during different negotiations.

Upon receiving a disclosure policy the compliance checker determines if it can be satisfied by any certificate of the local X - profile. How a policy is processed COMPLIANCE CHECKER TREE MANAGER Policy Base Policy Reply X-Profile Disclosure Policies Then, the module checks in the policy base the protection needs associated with the certificates, if any. The state of the negotiation is anyway updated by the tree manager, which records whether new policies and credentials have been involved or not.

Directions l Policies are of much interest to many organizations and applications - Financial, Medical, Retail, Manufacturing etc l Roles and responsibilities l Flexible policies l RBAC, UCON, RBUC, Trust Negotiation, Dissemination Policies l Need to Know to Need to Share l IEEE POLICY and ACM SACMAT