MDA and Security

October 12, 2006

FAU Secure Systems Group

Patrick Morrison

Agenda

• Motivation for “MDA and Security”• Secure Systems Methodology, with patterns• A quick tour of MDA, in English this time• Example Application• MDA in the development lifecycle• Evaluation Criteria• Contributions• Next Steps

The problem of Security

• “A good percentage of the software deployed in industrial/commercial applications is of poor quality, it is unnecessarily complex, and contains numerous flaws that can be exploited by attackers.”

• “We believe that the solution lies in developing secure software from the beginning, applying security principles along the whole life cycle…We see the use of patterns as a fundamental way, even for developers with little experience, to implicitly apply security principles.”

• [MDSSP, EBF, et. al.]

Secure Systems Methodology [MDSSP]

Security verification and testing

Requirements Analysis Design Implementation

Secure UCs Authorization rules in conceptual model

Rule enforcement through architecture

Language enforcement

Security test cases

Stage Tasks

Requirements Use case based role and attack analysis

Analysis Authorized semantic analysis patterns

Design Coordinated application of patterns to multiple architectural layers

Implementation MDA Code Generation

Methodology PatternsSecureLayers

SecureFacade

SecureReflection

ApplicationConceptual

Model

PolicyAdministration

Point

PolicyInformation

Point

PolicyDecision

Point

PolicyEnforcement

Point

Model ViewController

SecureAdapter

SecureBroker

SecureEnterprise

ComponentFramework

SecureWeb

Services

SecureProxy

AuthenticationSecure

Channel

SecureClient

DispatcherServer

SecureRelationalDatabaseMapping

SecureOperating

System

defineRules

enforceRules

decide

interact transformInterfacedistribute

objects consume/provideServicesimplement

businessmodel

mapObjects accessRemoteobjects

supportSoftware secure

Communication

establishConnection

authenticate

use

use

Design (and other) patterns

• “A design pattern names, abstracts and identifies the key aspects of a common design structure that makes it useful for creating a reusable object-oriented design” [GOF, pg 3]

The promise of MDA

• by using “precise but abstract and graphical representations of algorithms, MDA allows the construction of computing systems from models that can be understood much more quickly and deeply than can programming language “code” [MDAD, pg. xiv].

The Question(s)

• Can MDA be applied to the design and construction of secure systems?

• To what degree is it now possible to work in terms of high-level models rather than code?

• Does MDA allow for the creation and reuse of generic models?

• Does MDA reduce the amount of low-level work that needs to be done?

Combining Patterns, Security and MDA: SOUPCAN

• Secure grOUP Chat Application for Networks

• Provide invitation-only chat rooms with secure communications, allowing participants to form “cliques” in order to gossip, plan wars, etc…

• Example of using the secure systems methodology with MDA

SOUPCAN

• Requirements chosen to facilitate use of existing security patterns, e.g. Reference Monitor, Authenticator, Authorizer, Credentials, Secure Broker

• (Hopefully) Small enough to be implementable• (Hopefully) Large enough to illustrate issues in

application of MDA, Secure Systems with Patterns Methodology.

Lifecycle Step: Analysis

• Process: Evaluate requirements, identify use cases, high-level structure, apply patterns where appropriate

• Results: Application model containing UML Use Case and Class diagrams

SOUPCAN Use Cases

• UML Built with MagicDraw• Stored as XMI data• Excerpt: <UML:Actor xmi.id="249272_1" name="Host" />   <UML:Actor xmi.id="940417_17" name="Participant" />   <UML:Actor xmi.id="448524_33" name="Administrator" />   <UML:UseCase xmi.id="949209_49" name="Administration" />   <UML:UseCase xmi.id=“838290_60" name="Invitation" />   <UML:UseCase xmi.id="896208_71" name="Registration" />   <UML:UseCase xmi.id="428793_82" name="Chat" /><UML:Association xmi.id="975434_95"><UML:Association.connection>  <UML:AssociationEnd xmi.id="250191_93" isNavigable="true"

participant="249272_1" />   <UML:AssociationEnd xmi.id="742224_94" isNavigable="true"

participant="838290_60" />   </UML:Association.connection>  </UML:Association>

Lifecycle Step: Design

• Process: Develop class and sequence diagrams which implement the Use Cases, apply patterns where appropriate

• Results: Application and Security models containing UML Class and sequence diagrams

SOUPCAN Class Diagram

SOUPCAN Class Diagram

It’s (Secure) Broker!

Architectural concerns for implementing Secure Broker

SecureChannel

Broker

DigitalSignature

Client DispatcherServer

Authentication

AccessMatrix

ReferenceMonitor

RBAC

confidentiality

authentication

authorization

authorization

enforces

non-repudiation

implementAs

* Diagram from MDSSP

Lifecycle Step: Implementation

• Process: Select a platform and platform model, make connections between the design and the platform, via the platform model

• Selected: MagicDraw, androMDA, C#, ASP.NET, Visual Studio, nHibernate, …

• Results: Code generated from the models

Implementation Details… :32,997 - discovering namespaces - :34,440 found namespace --> 'aspdotnet' :34,440 + registering component 'cartridge' :34,870 + registering component 'metafacades' :35,331 + registering component 'profile' :40,628 found namespace --> 'uml-1.4' :40,628 + registering component 'metafacades' :41,960 + registering component 'profile' :42,000 found namespace --> 'validation' :42,010 + registering component 'translation-library' :53,948 - core initialization complete: 22.373[s] - :54,568 loading model --> 'file:C://TimeTracker.Model.xmi' :58,905 referenced model --> 'jar:file:/uml14/profile/profile-.xml' :59,045 referenced model --> 'profile-datatype.xml' :59,285 referenced model --> 'profile-service.xml' :59,445 referenced model --> 'profile-process.xml' :59,576 referenced model --> 'profile-presentation.xml' :59,746 referenced model --> 'profile-meta.xml' :59,866 referenced model --> 'profile-xml.xml' :59,986 referenced model --> 'andromda-profile-persistence.xml' :01,118 - loading complete: 7.13[s] - :01,118 - validating model - :06,175 - validation complete: 5.057[s] - :07,076 INFO [AndroMDA:cs] Output: 'file:/C:../TimeTracker/VO/UserVO.cs'

// Name: UserVO.cs// Attention: Generated code! Do not modify by hand! (I did anyway)// Generated by: ValueObject.vsl in andromda-cs-cartridge.using System;namespace Northwind.TimeTracker.VO{ [Serializable] public class UserVO { #region Attributes and Associations private long _id; private String _userName; private String[] _roles; #endregion #region Constructors public UserVO(long id, String userName, String[] roles) { this._id = id; this._userName = userName; this._roles = roles; }…

Mapping…

Evaluation

• Does the generated code implement the design? Can users of the system chat?

• How secure is the system? Is it correlated to the design models?

• How independent are the Application, Security and Platform models? Can, for example, the Security model be reused with a different application model? With a different platform model?

• Does MDA keep its promise? How much programming language coding needs to be done?

Contributions

• A UML Model for security, based on patterns• A worked example of the Secure Systems

Methodology, through Analysis, Design and Implementation.

• A worked example of MDA development• Description of a tool chain for building MDA

applications (MagicDraw, androMDA, Visual Studio 2005, etc)

• An example application, with requirements and design.

Next Steps…

• Complete design of SOUPCAN

• Split design into separate Application and security models, link them

• Document experiences, issues with using the current tools