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Security Concepts and Capabilities CSE 333 Prof. Steven A. Demurjian, Sr. Computer Science & Engineering Department The University of Connecticut 371 Fairfield Road, Box U-1155 Storrs, CT 06269-1155 [email protected] http://www.engr.uconn.edu/~steve (860) 486 - 4818 The majority of these slides represent material that has been accumulated from various sources over the years. A portion these slides are being used with the permission of Dr. Ling Lui, Associate Professor, College of Computing, Georgia Tech. SecBG-1 Overview CSE 333 Concepts and Issues Glossary of Security Terms Security Policy, Authentication, and Authorization Security in Java Database Security Access Control Mandatory Access Control (MAC) Discretionary Access Control (DAC) Role-Based Access Control (RBAC) Cryptography Security in Statistical DB Emerging Security Trends SecBG-2 Introduction: General Concepts CSE 333 Authentication Proving you are who you are Signing a Message Is the Client who S/he Says they are? Authorization Granting/Denying Access Revoking Access Does the Client have Permission to do what S/he Wants? Encryption Establishing Communications Such that No One but Receiver will Get the Content of the Message Symmetric Encryption Public Key Encryption SecBG-3 Type of Security Issues CSE 333 Legal and Ethical Issues Information that Must be Protected (e.g., SSN) Information that Must be Accessible (e.g., SSN) Policy Issues Who Can See What Information When? Applications Limits w.r.t. Data vs. Users? System Level Enforcement What is Provided by the DBMS? Programming Language? OS? Application? How Do All of the Pieces Interact? Multiple Security Levels/Organizational Enforcement Mapping Security to Organizational Hierarchy Protecting Information in Organization SecBG-4 Glossary of Protection and Security Terms CSE 333 Principal Entity (Person/Process/etc.) to Which Authorizations are Granted Can be a User, User Group, Program, Client, etc. Also Known as Subject Protected Object Known Object whose Internal Structure is Inaccessible Except by Protection System The Unit of Protection For Our Purposes: Table, Column, Tuple Data and Meta-Data Glossary from: Saltzer and Schroeder, “The Protection of Information in Computer Systems”, Proc. of IEEE, Vol. 63, No. 9, September 1975. SecBG-5 Glossary of Protection and Security Terms CSE 333 Access Control List List of Principals (User, User Group, Process, …) Authorized to have Access to Some Object For Every Object, Maintain Authorized Principals Easily Implemented in Algorithm/Typically in OS Authenticate Verify Identity of Principal Making Request In OS - Equivalent to Logging on (ID, Password) May be More Complicated Based on Security Needs Authorize Grant Principal Access to Objects Granularity Ranges from Fine to Coarse Application Directed SecBG-6 Glossary of Protection and Security Terms CSE 333 Capability Unforgeable Ticket as Proof of Authorization of Presenter (Principal) to Access Named Object Ticket or Certificate Must be Presented at Each Access Capability List List of Protected Objects which Likewise List Authorized Principles Used in Conjunction with Tickets for Authorization Certify Verify Accuracy, Correctness, & Completeness of Security/Protection Mechanism Critical for Select Domains (DoD, Banking, etc.) SecBG-7 Glossary of Protection and Security Terms CSE 333 Confinement Restricting What a Process Can Do to with Authorized Objects Similar in Concept to Sandbox of Java Domain Objects Currently Accessed by Principal (De)Encryption De(Encoding) of Data According to Transformation Key for Transmission/Storage Reciprocal Activity - Many Different Options Grant Authorize Access to Objects by Principals Who Can do What When SecBG-8 Glossary of Protection and Security Terms CSE 333 Password Encrypted Character String to Authenticate Identity of Individual Critical to Encrypt Also from Client to Login Server Client Types in Plain Text that is Encrypted Encrypted login Travels of Network Decrypted at Login Server and Verified Permission Form of Allowed Access to Object (R, W, RW) Level of Access is System Dependent Unix File System has: r, w, x for User, Group, and Other SecBG-9 Glossary of Protection and Security Terms CSE 333 Privacy Ability to Decide Whether, When, and to Whom Information is Released Is Anyone Intercepting Client/Server Communications? Propagation Principal Passing on Authorization to Object to Another Principal Current Term Today is “Delegation” Principal Must be Authorized to Delegate Privileges to Another Principal Enforcement Mechanism Centralized and Distributed “Code” Enforces Security Policy at Runtime SecBG-10 Glossary of Protection and Security Terms CSE 333 Protection & Security Mechanisms and Techniques to Control Access to Information by Executing Programs Enforcement Mechanism, Cryptography Algorithms, Database Security, etc. Revoke Remove Previously Authorized Access from Principals Security Tools Must Promote Grant, Revoke, and Authorize in a Dynamic Setting Ticket-Oriented Each Principal Maintains List of Unforgeable Tickets Denoting Objects have been Authorized Works with Capability Lists SecBG-11 Policy & Mechanism CSE 333 Security Policy Defines Rules for Authorizing Access to Computer and Resources Who are Users? What are DB Items? What DB Items are Available to Each User? Etc… Protection Mechanisms Authenticate Access to DB Items Insure File and Memory Protection A Security Policy is an Organizations Strategy to Authorize Access to the DBMS DB Items Each Policy is Application Dependent Range from Full to Limited Access Security Transcends DB as a Separate Research and Realization for All Types of Systems/Applications SecBG-12 Authentication CSE 333 User/Process Authentication Is this User/Client Who It Claims to Be? Passwords More Sophisticated Mechanisms Authentication in Networks Is this Computer Who It Claims to Be? File Downloading and Transferring Obtaining Network Services What is Java Promise? What Does Java Guarantee re. Applets? What can Application do that Applet Can’t? DB Authentication Uncontrolled Access (Select, Modify, etc.) Can be Limited (Authorized) requiring Authentication SecBG-13 Authorization CSE 333 Ability of Principals to Use Machines, Objects, Resources, etc. Security Policy Defines Capabilities of Each Principal Against Objects, Resources, etc. Authorization Mechanism Enforces Policy at Runtime External Authorization User Attempts to Access Computer Authenticate Identify and Verify Authorizations Internal Authorization Can Process Access a Specific Resource? Database Authorization What Can Each User Do Against the DB? Select, Insert, Update, Delete? Are Users Limited to Subsets of Tuples by Value? SecBG-14 User Authentication CSE 333 Combination of User ID and Password Universal for Access to Computers However, Cannot Prevent … Guessing of Passwords Stolen and Decrypted Passwords Masquerading of Intended User Is User Who they are Supposed to be? What Extra Information Can User be Asked to Supply? What About Life Critical Situations (DCP)? Past Invasion of Engineering Computing yppasswd File Stolen/Decrypted S. Demurjian’s Sun Workstation Corrupted SecBG-15 Network Authentication CSE 333 Computers Must Interact with One Another Classic Example, Transmitting E-Mail Msgs. Does Transferring Computer have Right to Store a File on Another Computer? Viruses: Passive Penetrating Entity Software Module Hidden in Another Module When Container Executed, Virus Can Penetrate and Wreak Havoc Worms: Active Penetrating Entity Actively Seeks to Invade Machine Morris’s Worm Penetrated via Unix Finger Passed String that Executed Allocated Memory Destroyed Runtime Stack/Allowed Worm Execute SecBG-16 Core Security Capabilities of Java CSE 333 Sandbox and Applet Level Security Downloaded Applets are Confined in a Targeted Portion of System During Execution Execution of Untrusted Code in Trusted Way What is Sandbox? Area of Web-Browser Dedicated to Applet Applet Limited to Sandbox to Prohibit Access to Local Machine/Environment Utilizes Class Loader, Bytecode Verifier, and Security Manager Three Components Maintain System Integrity How Does this Occur? SecBG-17 Core Security Capabilities of Java CSE 333 Class Loader - Only Load Correct Classes Bytecode Verifier - Classes in Correct Format Security Manager - Untrusted Classes Can’t Execute Dangerous Instructions nor Access Protected System Resources Role of Security Managers Enforces Boundaries of Sandbox All Java Classes ask Manager for Permission to Perform Certain Operations Implements/Imposes Appl. Security Policy Java Interface Class Implementable by Users Integrated with Exception Handling of Java SecBG-18 Recall Java Bytecode Verification: CSE 333 SecBG-19 Digital Signatures and JAR Files CSE 333 When Can Applets Become Applications? Trusted Publisher (Originator of Applet) Signed Applet is Authenticated Java Security Manager May Allow Applet out of Sandbox to be Application How is Information Transmitted and Exchanged? JAR: Archived (Compressed) Files Bundling of Code/Data into Java Archive Associated Digital Signature for Verification Transmission via Object Serialization SecBG-20 Database Security Approach CSE 333 Software Engineers can Write Complex Programs Limited by Intellectual Capabilities DB Designer Must Create Protection Scheme that Can’t be Bypassed by Current and Future Software Users and DB Initiators Users have Dedicated and Shared DB Items DB Items Shared by User Groups vs. DB Items Globally Shared Users Spawn Clients that Access DB Items Clients May be Local or Remote (on Another Machine Connected via Network) Protection System of DB Must Support Above According to Organization’s Admin. Policy SecBG-21 Database Security CSE 333 Types of Security Database Security is Mainly Related with Access Rights to the Database Database Security Involves Issues Such as Governmental or Corporate Level of Policies Privacy and Confidentiality Requirements For Example - Consider a Medicine Prescription Physician or PA Only One Authorized to Write Drug, Dosage, Refills, Generic vs. Brand, etc. Pharmacist by Law Can Enter Script, Replace Brand with Generic, Alter “Refills” - Can’t Change the Med By Law - Protect the Script per Patient (MD/Insurance) Access Control is Mechanism to Prevent Unauthorized Access to Databases SecBG-22 Database Security CSE 333 Database Administrator (DBA) has the Privileged Commands to Perform the Following on Databases Account Creation Privilege Granting Privilege Revocation Security Level Assignments Elements of the Security Model Subjects (Principals) Objects (Data) Access Methods (How to Use) Policies (Application Dictated) Authorizations (Who Can Do What) Authentication and Enforcement (Runtime) SecBG-23 Available Security Approaches CSE 333 Mandatory Access Control (MAC) Bell/Lapadula Security Model Security Classification Levels for Data Items Access Based on Security Clearance of User Role Based Access Control (RBAC) Govern Access to Information based on Role Users can Play Different Roles at Different Times Responsibilities of Users Guiding Factor Facilitate User Interactions while Simultaneously Protecting Sensitive Data Discretionary Access Control (DAC) Richer Set of Access Modes - Govern Access to Information based on User Id Discretionary Rules on Access Privileges Focused on Application Needs/Requirements SecBG-24 What are Key Access Control Concepts? CSE 333 Assurance Are the Security Privileges for Each User Adequate to Support their Activities? Do the Security Privileges for Each User Meet but Not Exceed their Capabilities? Consistency Are the Defined Security Privileges for Each User Internally Consistent? Least-Privilege Principle: Just Enough Access Are the Defined Security Privileges for Related Users Globally Consistent? Mutual-Exclusion: Read for Some-Write for Others SecBG-25 Mandatory Access Control CSE 333 Bell-Lapadula Model [1976] An Extension of the Access Matrix Model The Model is Based on Subject-Object Paradigm Subjects: Active Elements Objects: Passive Elements Four Access Modes/Categories Executable by Subjects on Objects Read-only or Read Append (Write without Read) Execute (Executes an Object/program) Read-Write or Write SecBG-26 Mandatory Security Mechanism CSE 333 Typical Security Classification Levels for Subjects/programs and Objects/resources Top Secret (TS) and Secret (S) Confidential (C) and Unclassified (U) Rules: TS is the Highest and U is the Lowest Level TS > S > C > U Security Levels: C1 is Security Clearance Given to User U1 C2 is Security Classification Given to Object O1 U1 can Access O1 iff C1 C2 This is Referred to as the Domination of U1 Over O1 SecBG-27 Operations CSE 333 Get access Initiate access to object in the given mode Release access Terminate access previously started by get Given access grant an access mode on an object to a subject Rescind access Revoke access previously granted with the “give” operation Create object An object may be inactive or active; this takes an inactive object and adds to the object hierarchy Delete object Deactivates an active object Change subject security level Change object security level SecBG-28 Mandatory Security Mechanism CSE 333 There are Numerous Security Properties Regarding the Ability of a Subject S to Read (Write) an Object O These Properties Control the flow of Information from Users to the Objects that they are allowed to Access Simple Security Property (Read Down – No Read Up) No Subject S Can Read an Object O if the Object’s Security Classification is Higher Than the Subject’s Security Clearance S Can Read O iff Clearance(S) Classification(O) This Insures that a Subject S cannot Read Information Above his/her Security Level TS S User (S) C U Read Down SecBG-29 Mandatory Security Mechanism CSE 333 Simple Integrity Property (Write Down–No Write Up) A Subject May Write an Object only if that Object is at or Below the Subject’s Security Clearance S Can Write O iff Clearance(S) ≥ Classification(O) This Allows the Potential of Information Flow from Higher Classification to Lower Classification Levels This Prevents the Ability of a Subject S to Corrupt Data above its Security Level Security Designer Must Choose their Poison! TS S User (S) C U Write Down SecBG-30 Mandatory Security Mechanism CSE 333 Liberal * Property (Write Up–No Write Down) No Subject May Write an Object that has Lower Security Class than the Subject’s Security Clearance S Can Write O iff Clearance(S) Classification(O) This Prevents Information Flow from Higher Classification to Lower Classification Levels Such an Attempt can be Overt or Unintentional Likewise, this Allows a Subject to Corrupt Information above its Level TS S C U Write Up User (S) SecBG-31 Mandatory Security Mechanism CSE 333 Strict * Property (Read/Write Equal) A Subject May Only Read/Write an Object that has the Exact Same Security Class than the Subject’s Security Clearance S Can Read/Write O iff Clearance(S) = Classification(O) This Limits Information Flow to within a Level TS S C U Read Equal Write Equal User (S) SecBG-32 Using the Properties CSE 333 Security Policy is Typically a Combination of one Read and one Write Property Simple Security + Simple Integrity Simple Security + Strict * (Write) Simple Security + Liberal * Strict * (Read) + Simple Integrity Strict * (Read) + Strict * (Write) Strict * (Read) + Liberal * Objective: Security Engineer Must Choose the Most Appropriate Combination for their Application SecBG-33 A Classic Example CSE 333 Simple Security for Reads See Information at User Clearance Level and Lower (Less Secure) No Chance of Viewing TS Information Liberal * for Writes Write Information at User Clearance Level and Above (More Secure) No Chance of Releasing “S” Data to Lower Levels User (S) TS S Read Down C U Write Up SecBG-34 Illustrating MAC CSE 333 Consider the EMPLOYEE Table Below with Two Instances Notice Classifications on Each Tuple (TC) Notice Classifications on Each Attribute Value Interpretation: Limit Who Can See Each Tuple and Values Focus on User Clearance w.r.t. Classifications SecBG-35 Illustrating MAC CSE 333 Whenever a User Attempts to Access a Table, the Table is Filtered According to U’s Clearance First Set are for a User at Confidential Level Second Set is For a User at Unclassified Level SecBG-36 Security in Software Applications CSE 333 Extensive Published Research (Demurjian, et al) in Last Ten Years for DAC/RBAC for OO Efforts in Automatically Generatable and Reusable Enforcement Mechanisms MAC/DAC/RBAC within Distributed Setting Premise: Customizable Public Interface of Class Access to Public Interface is Variable and Based on User Needs and Responsibilities Only Give Exactly What’s Needed and No More Please see: www.engr.uconn.edu/~steve/DSEC/desc.html SecBG-37 What is Role Based Access Control (RBAC)? CSE 333 Most OO Programming and Database Languages have a Single Public Interface that is Shared by All Users of OT/Class Consequently, Public Interface Often Union of all Possible Methods Required by All Likely Users Discretionary Access Control: Occurs at Type-Level Different Portions of Public Interface Available to Different Users at Different Times Depending on User-Roles Promote Potential Public Interface SecBG-38 Motivating Security for OO Paradigm CSE 333 OO Paradigm Provides Minimal Support via Public Interface and Private Implementation Public Interface Represents UNION of all Possible Privileges Needed by All Potential Users A Method in the Public Interface for One Specific User Available to ALL Users Can Access to Public Interface be Customized? Can Individuals have Particular Access to Specific Subsets of Public Interface? Can Access be Based on (Potentially) Dynamic User Roles? Can Code be Automatically Generated to Implement an Enforcement Mechanism? Role of OO Paradigm in Support a Generic, Evolvable, Reusable Enforcement Mechanism? SecBG-39 Why is RBAC Needed? CSE 333 In Health Care, different professionals (e.g., Nurses vs. Physicians vs. Administrators, etc.) Require Select Access to Sensitive Patient Data Suppose we have a Patient Access Client Lois playing the Nurse Role would be Allowed to Enter Patient History, Record Vital Signs, etc. Steve playing M.D. Role would be Allowed to do all of a Nurse plus Write Orders, Enter Scripts, etc. Vicky playing Admin Role would be Allowed to Enter Demographic/Insurance Info. Role Dictates Client Behavior SecBG-40 Why is RBAC Needed? CSE 333 Many Situations When Application Library Designer (SWE) Could Utilize More Fine-Grained Control to Access of Public Interface Tradeoff Between Developers and End-Users SWEs Have Different Roles Based on Their Responsibilities Related to Cooperative Design on an Application SWEs Should Only See Those Portions of the Application That They Need to See or That They Will Be Responsible for Implementing End-users Must Be Limited in Their Interactions and Access Depending on Their Roles SecBG-41 Examples of Why RBAC is Needed CSE 333 In HTSS, the public interface for Items has methods that read (for Scanner, I-Controller) and modify instances (only for I-Controller) Read Methods Targeted for Certain System Functions (e.g., Scan Item) Update Methods Targeted for Others (e.g., as Item is Scanned, Decrement Inventory Amount) In HCA, different health care professionals (e.g., Nurses vs. Physicians vs. Administrators, etc.) require select access to sensitive patient data Physician’s Write Scripts Nurses Enter Patient Data (Vitals + History) All Access Shared Medical Record Access is Limited Based on Role SecBG-42 RBAC for OO CSE 333 Public Interface is Union of All Privileges for All Potential Users No Explicit way to Prohibit Access Customizable Public Interface of Class Access to Public Interface is Variable and Based on User Needs and Responsibilities Only Give Exactly What’s Needed and No More public class PatientRecord { private: Data/Methods as Needed; public: write_medical_history(); write_prescription(); For MDs get_medical_history(); and Nurses get_diagnosis(); set_payment_mode(); etc… For MDs Only For Admitting SecBG-43 Sample RBAC Hierarchy for HCA CSE 333 Users Medical_Staff Support_Staff Etc. Nurse Physcian Technician UR:Lab UR:Pharmacy UR:Radiology UR:Staff_RN UR:Education UR:Private UR:Attending UR:Director UR:Manager UR:Discharge_Plng SecBG-44 Sample RBAC Hierarchy for University CSE 333 Users / \ +---+ +-----+ / \ non-academic-staff academic-staff / \ \ / \ \.... / \ \ / \ purchasing campus-police ... dept-staff registrar-staff ... / \ ... ... / \ grade-recording transcript-issuing SecBG-45 Discretionary Access Control CSE 333 Discretionary Grant Privileges to Users, Including the Capabilities to Access Specific Data Items in a Specific Mode Available in Most Commercial DBMSs Aspects of DAC User’s Identity Predefined Discretionary “Rules” Defined by the Security Administrator Focus on Two Variants of this Model Access Matrix Model Lampson’s Protection System Role Delegation and Delegation Authority Detail DAC in SQL2 SecBG-46 Access Matrix Model CSE 333 Proposed by Harrison, Ruzzo, and Ullman, 1976 Basic Concepts are S: Set of Subjects (Principals) O: Set of Objects (Data Items) A: The Access Matrix (Who can do What) Rows Correspond to the Subjects Columns Correspond to the Objects We’ll see a Variant of this in Lampson SecBG-47 Access Matrix Model CSE 333 Conditions Associated with Access Authorization Data-Dependent Specifying Constraints on the Value of Accessed Data Time-Dependent Specifying Constraints on the Time When an Access can Take Place Context-Dependent Specifying Constraints on Combinations of Data Which can be Accessed History-Dependent: Specifying Constraints Dependent on Previously Performed Accesses SecBG-48 Access Matrix Model CSE 333 An Example Object Types: Relations, Views, Rows (records), Columns, Operations Subject Types: Users, Accounts, Programs object subject S1 S2 …. Sn O1 …. Oi …. Om A[S1,O1] A[S1,Oi] A[S1,Om] A[S2,O1] A[S2,Oi] A[S2,Om] A[Sn,O1] A[Sn,Oi] A[Sn,Om] SecBG-49 Access Modes CSE 333 Access Modes Read, Write, Append, and Execute Authorization A[S,O] is an Entry in the Access Matrix A[S,O] can be Authorized to One or More Operations Mechanisms <create> <subject Si > - Add a Row create> <object Oj> - Add a Column <destroy> <subject Si > - Remove a Row <destroy> <object Oj> - Remove a Column <enter> <operation x into A[Si, Oj] <delete> <operation x from A[Si, Oj] SecBG-50 What is Role Delegation? CSE 333 Role Delegation, a User-to-User Relationship, Allows an Original User (OU) to Transfer Responsibility for a Particular Role to a Delegated User (DU) Two Major Types of Delegation Administratively-directed Delegation has an Administrative Infrastructure Outside the Direct Control of a User Mediates Delegation User-directed Delegation has an User (Playing a Role) Determining If and When to Delegate a Role to Another User In Both, Security Administrators Still Oversee Who Can Do What When w.r.t. Delegation SecBG-51 Why is Role Delegation Important? CSE 333 Many Different Scenarios Under Which Privileges May Want to be Passed to Other Individuals Large organizations often require delegation to meet demands on individuals in specific roles for certain periods of time True in Many Different Sectors Financial Services Engineering Academic Setting Key Issues: Who Controls Delegation to Whom? How are Delegation Requirements Enforced? SecBG-52 What Can be Delegated? CSE 333 Authority to Do the Task, Carries the Least Responsibility Necessary to Execute the Task, but Does Mean the Delegated User Can Execute the Delegated Task or Role. Responsibility to Do a Task Implies Accountability and a Vested Interest that a Task or Role Can Be Executed Properly. Duty to Perform a Task Implies that the Delegated User is Obligated to Execute the Given Task. Our Focus: Delegate Authority Only SecBG-53 Delegation/Pass on Delegation Authorities CSE 333 When Establishing Privileges (by the Security Officer) there must be the Ability to Define: Delegation Authority (DA) Recall:Security Officer can Delegate a Role to User DA Means that the Security Officer Can Delegate the Authority to Delegate to another User Role Can be Delegated by one User to Another However, Delegation Authority Cannot Pass-on Delegation Authority (PODA) PODA Augments DA to Allow the Delegation Authority to Also be Delegated as Part of the Delegation of a Role to a User SecBG-54 Example - Role Delegation CSE 333 General DoBest Delegates his Role CDR_CR1 (Commander, Crisis 1) to Colonel DoGood with DA, where DoBest, CDR_CR1, and DoGood defined as: OU: [DoBest, [ct, ], T] UR: [CDR_CR1, [01dec00, 01dec01], T] UA: [DoBest, CDR_CR1, [01dec00, 01dec01]] DA: Yes PODA: Yes After Delegation: DU: [DoGood, [01dec00, 01jun01], T] UA: [DoGood, CDR_CR1, [01dec00, 01jun01]] SecBG-55 Example - Role Delegation CSE 333 Now, Colonel DoGood wishes to re-delegate CDR_CR1 to Major CanDoRight, which can be defined as: DU: [DoGood, [01dec00, 01jun01], T] UR: [CDR_CR1, [01dec00, 01dec01], T] UA: [DoGood, CDR_CR1, [01dec00, 01jun01]] DA: Yes PODA: No After Delegation: DU: [CanDoRight, [01jan01, 01feb01], T] UA: [CanDoRight, CDR_CR1, [01dec00, 01jun01]] SecBG-56 Role Delegation Revocation Rules CSE 333 User-to-User Delegation Authority Rule A User (OU or DU) Who is a Current Member of a Delegatable Role (DUR), Can Delegate that User Role to Any User that Meets the Prerequisite Conditions of the Role: DU Receiving the Role is Not a Member of the Role; OU or DU is Identified As Having Delegation Authority for the Role; DU Meets the Mandatory Access Control Constraints (MACC). SecBG-57 Role Delegation Revocation Rules CSE 333 Delegation Revocation Authorization Rule: An Original User Can Revoke Any Delegated User From a User Role in Which the OU Executed the Delegation. This is a Stricter Interpretation than [Zhan01], Which Allows Any OU of a Role Revocation Authority Over a DU in the Delegation Path. In Addition, a Security Administrator Can Revoke Any Delegation. Cascading Revocation Rule: Whenever an OU or DU in the delegation path is revoked, all DUs in the path are revoked. SecBG-58 Monotonicity and Permanence CSE 333 Definition: Monotonicity Refers to the State of Control the OU Possesses After Role Delegation Monotonic Delegation Means That the OU Maintains Control of the Delegated Role Non-monotonic Means That the OU Passes the Control of the Role to DU Definition: Permanence Refers to Delegation in Terms of Time Duration Permanent Delegation is When a DU Permanently Replaces the OU Temporary Delegation Has an Associated Time Limit With Each Role SecBG-59 Totality and Administration CSE 333 Definition: Totality Refers to How Completely the Permissions Assigned to the Role Are Delegated Partial Delegation Refers to the Delegation of a Subset of the Permissions of the Role Total Delegation Refers to the Situation All of the Permissions of the Role Are Delegated Definition: Administration Refers to how Delegation will be Administered User Directed is when the User Controls all Aspects of Delegation Administrator-Directed (Third party, Agentdirected) is when Control is with the Security Officer SecBG-60 Revocation CSE 333 Definition: Cascading Revocation Refers to the Indirect Revocation of All DUs When the OU Revokes Delegation or Administration Revokes the OU’s Delegated Role Definition: Grant-Dependency Revocation Refers to Who Has Authority to Revoke a DU Grant-Dependent Revocation Only Allow the OU to Revoke the Delegated Role Grant-Independent Revocation Allows Any Original Member of the DUR to Revoke a Delegated Role SecBG-61 DAC in SQL2 CSE 333 SQL2 Uses the Concept of Authorization Identifier User Group (could be Single User) References a Set of User Accounts DBA Must Provide Selective Access by each User to Every Relation in the DB Based on Account Two Levels of Privilege Assignment Account Level - DBA Manages the Accounts for to Authorize Users to Different DBs Relation/Table Level - Controlling Access to Each Relation or View in a DB Objective Manage and Administer Design/Realize the Security Policy SecBG-62 Privileges in SQL CSE 333 Allocated at a Relation Level SELECT Privilege Gives Account Retrieval Access MODIFY Privilege Gives Account Ability to Change the Database Subdivided into Insert, Update, and Delete Insert and Update can be Specialized on Different Attributes of Relation REFERENCES Privilege Gives Account the Ability re. Integrity Constraints Can be Restricted to Certain Attributes of Relation Commands to both GRANT and REVOKE are Supported SecBG-63 Example Schema CSE 333 Consider Two Database Tables: EMPLOYEE (NAME, SNN, BDATE, ADDRESS, SET, SALARY, DNO) DEPARTMENT (D#, DNAME, MGRSNN) Consider Four Accounts/Users: U1, U2, U3 and U4 Limit U1 to be Able to Create Schema In SQL GRANT CREATETAB TO U1; In SQL2 CREATE SCHEMA EXAMPLE AUTHORIZATION U1; U1 Can Create Tables In Schema EXAMPLE SecBG-64 SQL Examples CSE 333 Suppose U1 Wants to Grant U2 the Ability to Insert and Delete into EMPLOYEE and DEPARTMENT U1 Wants to Disallow Ability of U2 to Propagate (Delegate) Insert/Delete to Other Users GRANT INSERT, DELETE ON EMPLOYEE, DEPARTMENT TO U2; Suppose U1 Wants to Grant U3 the Ability to Select from EMPLOYEE and DEPARTMENT U1 Allows U3 to Propagate to Other Users GRANT SELECT ON EMPLOYEE TO U3 WITH GRANT OPTION; Now, U3 can: GRANT SELECT ON EMPLOYEE TO U4; U4 Cannot Propagate/Delegate this Privilege SecBG-65 SQL Examples CSE 333 Suppose U1 Wants to REVOKE U3 the Ability to Select from EMPLOYEE and DEPARTMENT REVOKE SELECT ON EMPLOYEE TO U3; Database Must Also Cascade this Revoke to U4 Since U3 No Longer has the Ability to Grant Cascading Revokes Can be Complicated as Privileges are Defined Consider 100 Users and DB with 20 Tables and Ability to Grant/Revoke Becomes Complex Consequently, Propagation/Delegation are Usually Only Given Very Carefully Critical to Document Security Policy for Each Application! SecBG-66 SQL Examples CSE 333 Suppose that U1 wants to Give Back to U3 a Limited Capability to SELECT from EMPLOYEE Also Allow U3 to be able to Propagate U1 First Creates a View create view U3_EMP as select NAME, BDATE, ADDRESS from EMPLOYEE where DNO = 5; U1 Now Grants the View GRANT SELECT ON U3_EMP TO U3 WITH GRANT OPTION; U1 Can also Grant Limited Update GRANT UPDATE ON EMPLOYEE (SAL) TO U4; SecBG-67 Cryptography CSE 333 Information can be Encoded Using a Key it is Written (or Transferred) -- Encryption Information is then Decoded Using a Key When it is Read (or Received) -- Decryption Very Widely Used for Secure Network Transmission Mathematical Basis - Prime Number Generation encryption plaintext ciphertext decryption SecBG-68 More on Cryptography CSE 333 plaintext plaintext Ke Encrypt Side information Kd C = EKe(plaintext) Invader Decrypt plaintext SecBG-69 Cryptographic Systems CSE 333 Cryptographic Systems Modern Systems Conventional or Symmetric Systems •Ke and Kd are Private Key Public Key essentially the same •Ke and Kd are •Ke is public private •Kd is private SecBG-70 Statistical Database Security CSE 333 Statistical Databases are used to Produce Statistics on Various Populations Individual Information is Considered Confidential Users May be Allowed to Access Statistical Information on the Population, i.e., Applying Statistic Functions to a Population of Tuples Techniques for Protecting Privacy of Individual Information Solutions are Illustrated by Examples: Person(name, ssn, income, address,city, state, zip, sex, last_degree) Suppose we are Allowed to Retrieve Only the Statistical Information Over this Relation by Using SUM, AVG, MIN, MAX, COUNT, Etc. SecBG-71 Example of Statistical DB CSE 333 Consider Q1 and Q2: Q1: find the total number of women who have ph.D. and live in Calgary, Alberta. select COUNT(*) from Person where last_degree = “ph.D.” and sex = “F” and city = “Calgary” and state = “Alberta”; Q1: find the average income of women who have ph.D. and live in Calgary, Alberta. select AVG(income) from Person where last_degree = “ph.D.” and sex = “F” and city = “Calgary” and state = “Alberta”; Suppose Mary Black is a Ph.D who Lives in Calgary and we want to know her Income, which is Prohibited If Query Q1 Returns One Tuple, then the Result of Q2 is the Income of Mary Otherwise we May Issue a Number of Subsequent Queries Using MAX and MIN, we May Easily Obtain a Close Range of Mary’s Income SecBG-72 Example Two of Statistical DB CSE 333 The Issue is that Even with Statistical DB Limits, it is Possible to Infer and Discern Confidential Info. Suppose the Query Writer (Connie) also Lives in Calgary and has a Ph.D. Consider Q3 (left) and Q4 (right) below: select from where and and and and SUM(income) Person last_degree = “ph.D.” sex = “F” city = “Calgary” state = “Alberta”; name <> “Mary” select from where and and and and SUM(income) Person last_degree = “ph.D.” sex = “F” city = “Calgary” state = “Alberta” name <> “Connie”; Since Connie Knows her Own Income, by Calculating Q4 - (Q3 - Connie’s Income), She Determinds Mary’s Income SecBG-73 Statistical Database Security CSE 333 Thus, having Just Aggregate Operations Can Allow the Confidentiality of DB to be Breached A Number of Restrictions can be used to Reduce the Possibility of Deducing Individual Information from Statistical Queries: Statistical Queries are not Permitted if the Number of Tuples in the Population Specified by the Selection Condition Falls Below Some Threshold Restricting the Number of Tuples in the Intersection of Subsequent Query Results Prohibiting Sequences of Queries that Refer Repeatedly to the Same Population of Tuples While these can help - it may Still Possible to Deduce Information and Breach Confidentiality! SecBG-74 Public Policy on Security CSE 333 How do we Protect a Person’s DNA? Who Owns a Person’s DNA? Who Can Profit from Person’s DNA? Can Person’s DNA be Used to Deny Insurance? Employment? Etc. How do you Define Security Limitations/Access? Can DNA Repositories be Anonymously Available for Medical Research? Do Societal Needs Trump Individual Rights? Can DNA be Made Available Anonymously for Medical Research? International Repository Might Allow Medical Researchers Access to Large Enough Data Set for Rare Conditions (e.g., Orphan Drug Act) Individual Rights vs. Medical Advances SecBG-75 Security Solutions for Systems/Databases CSE 333 Pfizer UConn Health Center UConn Storrs Johns Yale Hopkins Bayer Info. Sharing - Joint R&D Company and University Partnerships Collaborative Funding Opportunities Retrofit Security Infrastructure Cohesive and Trusted Environment Existing Systems/Databases and New Applications How do you Protect Commercial Interests? Promote Research Advancement? Free Read for Some Data/Limited for Other? Commercialization vs. Intellectual Property? NIH FDA NSF Balancing Cooperation with Propriety SecBG-76 Concluding Remarks CSE 333 Security in DB is Part of an Overall Security Strategy Definition of Security Requirements Realization of Security at Application Level Integration of Security from User to OS to DB Rigorous Definition of Security Policy Dynamic Nature of Security Privileges Enforcement of Defined Privileges at Application and DB Levels Overall, Security in Today’s World Integral Part of Everyday Life - Some Key Concerns Confidentiality of an Individuals Data Identity Theft Protecting National Infrastructure SecBG-77