Web Application Security Reloaded for the HTML5 era

@carlobonamico#devoxxuk Web Application Security Reloaded for the HTML5 era Carlo Bonamico @carlobonamico carlo.bonamico@nispro.it http://www.nispro.it Designing and implementing secure Single Page Applications https://wall-simple.sli.do/#/event/cmnxxfl0/section/18289/questions

@carlobonamico#devoxxuk About me Speaker Bio – passionate software developer since the C128 era – PhD and research at the University of Genova / CNIT National TLC Research Consortium – exciting time at startup Eptamedia – now a Solution Architect and Senior Trainer at NIS s.r.l.  between Italy and new London office Current projects & interests – training/mentoring teams on AngularJS, Web Security, Continuous Integration & Delivery – creating component-based Angular applications – security reviews and assessments

@carlobonamico#devoxxuk Abstract Ten years after the first OWASP Top Ten list of Web Application Security risks has been published, the basics of protecting a typical JEE/Rails/PHP/.NET, webapp are becoming mainstream knowledge (although never enough, as the endless series of high profile vulerabilities demonstates). But the industry-wide move towards HTML5 and Single Page Applications, motivated by the opportunity for more sophisticated interaction and UX, is again upsetting the balance between Hackers and Developers. A wave of new-generation front-end technologies such as Web Components, AngularJS and Ember is Developers are attracting Developers with their combination of productivity and innovative UX, but at the same time opens the door to new vulnerabilities and security challenges. This talk will summarize the main principles of Secure Coding, and will discuss their application to HTML5 applications that interact with REST or WebSocket backends to prevent major risks (including OWASP Top Ten). A concrete example will demonstrate the use of tools and libraries, from RBAC to JWT, from Spring Security to AngularJS modules for implementing secure HTML5/JS apps.

@carlobonamico#devoxxuk Evolution of Application Security When I taught my first Web Application Security training – most participants had never heard of SQL Injection and XSS Thanks to many industry and community players (especially OWASP), – not to mention many high-profile incidents, things have started to change... Application Security Ensuring Application guarantees •Confidentiality •Integrity •Availability •Accountability of the Information it processes

@carlobonamico#devoxxuk Are we doing better? It's 2015... we were promised flying cars... and what we got is... See also – http://www.cvedetails.com/vulnerabilities-by-types.php – https://www.whitehatsec.com/resource/stats.html

@carlobonamico#devoxxuk Enter HTML5 After years of playing catch-up with Desktop, the Web is now often the default development target – powerful APIs – interactivity – always up-to-date & cross-platform the mobile web just adds more push to that => the rise of the Single Page Application Somewhat ill-defined term, but you know what I mean – HTML templates, statically served – client retrieves data from REST services / websockets – views dynamically rendered on the client side

@carlobonamico#devoxxuk HTML5 apps Definitely more powerful that traditional request-response webapps also more secure?

@carlobonamico#devoxxuk First problem Spiderman's Uncle Ben version: With great power comes great responsibility... The Web Application Security version: With great power come more holes and greater risks! – increased Surface of Attack  Websockets, storage, apis... – https://html5sec.org/ – http://html5security.org/ – and once you penetrate the browser, you can do basically everything  and I mean it: calling APIs, install keyloggers, redirect user behaviour, capture private data –http://xenotix.in/ “most attack were already possible... but they are more powerful now” http://w3af.org/understanding-html5-security

@carlobonamico#devoxxuk Second problem We are undergoing a wide architectural shift from To So many security assumptions do not hold true anymore! ServerPOST params HTML Browser Form-based input HTML rendering HTML templating Controllers, Interaction Logic Business Logic Server POST JSON JSON Browser HTML rendering HTML templating Business Logic Interaction Logic REST endpoints

@carlobonamico#devoxxuk The good side The typical modern HTML5 application architecture has a single/main advantage: it forces at the very least a basic degree of separation between UI and business logic – even more so with Angular, Ember, React In our consulting/project/problem solving experience, the single biggest cause of – quality – performance – security problems is....

@carlobonamico#devoxxuk The good side The typical modern HTML5 application architecture has a single/main advantage: it forces at the very least a basic degree of separation between UI and business logic – even more so with Angular, Ember, React In our consulting/project/problem solving experience, the single biggest cause of – quality – performance – security problems is.... the mixing & coupling of UI and business logic

@carlobonamico#devoxxuk There's hope... If we properly understand the new architectural paradigm, we can turn it into an advantage Follow the principles of secure coding – Do not trust inputs – Minimize attack surface area (and window of opportunity) – Establish secure defaults – Principle of Least privilege – Principle of Defense in depth – Fail securely – Don’t trust services – Separation of duties (vs configuration) – Avoid security by obscurity – Keep security simple – Fix security issues correctly

@carlobonamico#devoxxuk Top Ten Web Application Risks – A1-Injection – A2-Broken Authentication and Session Management – A3-Cross-Site Scripting (XSS) – A4-Insecure Direct Object References – A5-Security Misconfiguration – A6-Sensitive Data Exposure – A7-Missing Function Level Access Control – A8-Cross-Site Request Forgery (CSRF) – A9-Using Components with Known Vulnerabilities – A10-Unvalidated Redirects and Forwards What's different between Request/Response apps and HTML5/SPAs?

@carlobonamico#devoxxuk What changes with HTML5/SPAs? RED → more critical ORANGE → different solution GREEN → easier – A1-Injection → same problem, same solution – A2-Broken Authentication and Session Management – A3-Cross-Site Scripting (XSS) – A4-Insecure Direct Object References – A5-Security Misconfiguration – A6-Sensitive Data Exposure – A7-Missing Function Level Access Control – A8-Cross-Site Request Forgery (CSRF) – A9-Using Components with Known Vulnerabilities – A10-Unvalidated Redirects and Forwards We will focus on those!

@carlobonamico#devoxxuk A3-Cross-Site Scripting (XSS)

@carlobonamico#devoxxuk A3 - XSS Cross-Site-Scripting means that attacker can insert custom js code which is then displayed in the user browser – stored (input js in a field → DB → sent back to the page) – reflected (input js in the url, send the url to a user, js executed) – DOM-based (input triggers js logic that manipulates the DOM and insert custom js) Remember: any external input is UNTRUSTED! – so we must avoid mixing user input with js code

@carlobonamico#devoxxuk A3 – Preventing XSS Looks easy: but HTML allows for multiple mixed execution contexts: – JS within CSS within HTML within a frame of another HTML … The proper solution is ESCAPING: encoding the data so that the browser properly interprets it as plain text (and not js) – https://www.owasp.org/index.php/XSS_(Cross_Site_Scripting)_Prevention_Che at_Sheet In a well designed SPA, – clear inputs paths  REST service responses, user inputs, url bar, ... – HTML generation through the framework templating engine – so it is easier to intercept and escape outputs

@carlobonamico#devoxxuk A3 – Preventing XSS with Angular Since 1.3, the HTML compiler will escape all {{}} & ngbind by default – https://www.ng-book.com/p/Security – http://java.dzone.com/articles/angularjs-how-handle-xss Be careful if you must include user-generated HTML (e.g. in rich text editors) – take advantage of the services and directives – ngbindhtml (from angular-sanitize)  print as is removing “script” tags (beware of img tags)  fully customizable with –$sceProvider & $SanitizeProvider – https://docs.angularjs.org/guide/security Please note: – escaping in the REST services is not always feasible/useful – they can be consumed by mobile Apps and other clients

@carlobonamico#devoxxuk More Angular-specific guidelines Further suggesions: – prefer model-based logic – avoid mixing client side and server side templating – clear template / data separation – avoid dynamically generating templates from user input – do not run input in $eval

@carlobonamico#devoxxuk A3 – XSS - Tools Static Code Analysis for DOM-based and reflected XSS – Mozilla ScanJS  https://github.com/mozilla/scanjs – JSPRime  https://github.com/dpnishant/jsprime More references – https://blog.nvisium.com/2014/06/javascript-security-tools.html

@carlobonamico#devoxxuk Remember Most vulnerabilities are not so serious by themselves – but became terrible if mixed  think Pepsi + Mentos XSS is an enabler for – phishing – browser-based MITM – session / auth token stealing – sensitive data extraction – img courtesy of http://www.delawaretoday.com/

@carlobonamico#devoxxuk A6-Sensitive Data Exposure Do you protect your cookies?

@carlobonamico#devoxxuk Securing cookies If your cookie is stolen – via Cross-Site-Scripting, interception, ... attacker is granted access to the session At the very least – always use HTTPS / TLS – set secure flag – set HTTPOnly flag Also, do not store sensitive data in clear in localStorage / sessionStorage indexDB

@carlobonamico#devoxxuk A5-Security Misconfiguration

@carlobonamico#devoxxuk A5 – Security misconfiguration A single MITM (Man in the Middle) and your “done” – as the attacker can put arbitrary code in your browser – so,  https://www.eff.org/Https-everywhere Be careful with CORS – Avoid AllowOrigin “*” unless you have very strong authentication and authorization Remember to tell the browser to enable stronger protection – typically through headers such as CSP – https://www.owasp.org/index.php/List_of_useful_HTTP_headers

@carlobonamico#devoxxuk Securing Headers Node – https://www.npmjs.com/package/helmet Java (Spring Security) – http://docs.spring.io/autorepo/docs/spring-security/current/reference/html/headers. html Test tools – security headers online  https://securityheaders.com/ – OWASP ZAP  https://www.owasp.org/index.php/OWASP_Zed_Attack_Proxy_Project

@carlobonamico#devoxxuk A2-Broken Authentication & Session Management

@carlobonamico#devoxxuk What is Authentication Verifying the user identity – independently from his profile / authorizations Several elements: – where valid users are listed (Realm)  internal, file, DB, LDAP, Active Directory, SSO Server – what info is used to establish user identity  one or more “factors”: username, password, OTP, certificate... – how identity is checked the first time  login → credentials validation – how identity is checked on subsequent requests  validation

@carlobonamico#devoxxuk Traditional Request-Response Applications e.g. JSP / ASP / PHP – login page – successful login creates a session – protected pages accessed within the session – data and access control filtered on the server side  often within views or controllers Browser Server POST Login Data GET secured page SESSIONID = 5 SESSIONID = 5 auth = true? crede ntials valid? Realm filtered HTML page SID AUTH DATA 5 true carlo,admi n

@carlobonamico#devoxxuk Issues with Cookie + Session Authentication Authentication requires – checking credentials against a realm – keeping auth in session state on the server – sessionid sent in a cookie Issues – state replication in clustered servers vs sticky sessions  Single-Sign-On across servers? – More complex scenarios are possible  e.g. SSO Server, like CAS – typically cookie based → all server must be in same domain Remember: Cookies are sent with ANY request to the same domain (including images)

@carlobonamico#devoxxuk Cookie-based authentication in Single Page Applications Can't SPA just do the same? – login form POSTs to login service – successful login creates a session and sets a cookie – protected Pages & REST services accessed within the session  data and access control filtered … where ? Browser Server POST Login Data GET secured JSON SESSIONID = 5 SID AUTH DATA 5 true carlo,admi nSESSIONID = 5 auth = true?{ ... } crede ntials valid? Realm

@carlobonamico#devoxxuk Authentication vs Session Management Pros – simple to implement Cons – not suited to stateless nature of REST services Authentication vs Sessions – They are two different things, although often used together – REST services tend to be stateless Unauthenticated Authenticated Stateless Plain HTTP e.g. Wikipedia REST e.g. Google APIs With Session Session cookies e.g. Amazon JSP/ASP/PHP e.g. Intranet Apps

@carlobonamico#devoxxuk How to do stateless authentication?

@carlobonamico#devoxxuk Token-based Authentication Login establishes a valid token – each request must be presented with the token – the server can check token validity at each request – https://auth0.com/blog/2014/01/07/angularjs-authentication-with- cookies-vs-token/ Browser Server POST Login Data GET secured JSON TOKEN = 5 TOKEN = 5 token valid? crede ntials valid? Realm no session!

@carlobonamico#devoxxuk Issues Given a token – how do you know which is the current user? On the server – how expensive it is to check the token at each request? Can you share a token across services? – can you validate it without connecting to a DB / SSO Server?

@carlobonamico#devoxxuk How do you create & validate Tokens?

@carlobonamico#devoxxuk Creating and Validating Tokens Simplest way: checking them against a list of valid tokens – in memory → similar to session-based auth  replication problems – on a DB  easier clustering, must consider performance – on an external server  SSO for free, must evaluate performance & complexity

@carlobonamico#devoxxuk JWT - http://jwt.io JWT = encoded & signed Json object containing – Access token – Claims (custom: session, domain, username...) – Expiration – and Digital Signature! → verifiable with just the public key Returned by login REST service Sent as header at each request –Authentication: bearer eyJhbGciO .eyJzdWIiOWV9.eoaDV Checked by REST backed at each request – can also be used with websockets { “user”:”carlo”, “domain”:”NIS”, “expiry”: .. }

@carlobonamico#devoxxuk JWT in angular Angular Library – https://github.com/auth0/angular-jwt Extensible hooks for – storing and retrieving tokens on the client Interceptors for – retrieving tokens from server Response Headers – optionally refresh tokens – automatically sending tokens at each request Robust and simple to user bower install angularjwt

@carlobonamico#devoxxuk Token-based Auth in AngularJs Ingredients REST endpoints – /auth/login  Input parameters: credentials  Response: token – /auth/logout  Input parameters: token $http or $resource based Client Service AuthenticationService – login() logout() methods wrapping the above – plus isAuthenticated() and possibly currentUser()

@carlobonamico#devoxxuk Token-based Auth in AngularJs Ingredients – Controller(s) – LoginController  bound to Login form, calls service – LogoutController – AuthenticationController  IsAuthenticated, currentUser Possibly, Directives <authenticateduser> showWhenAuthenticated <menu showWhenAuthenticated=”true”>

@carlobonamico#devoxxuk Authentication Client Perform the request – Form based POST $http({ url: '/oauth2/token', method: 'POST', headers: { 'Content-Type': 'application/x-www-form-urlencoded' }, transformRequest: function (obj) { var str = []; for (var p in obj) str.push(encodeURIComponent(p) + "=" + encodeURIComponent(obj[p])); return str.join("&"); }, data: { username: credentials.username, password: credentials.password, } })

@carlobonamico#devoxxuk Authentication Client REST POST $http({ url: '/rest/auth/token', method: 'POST', data: { username: credentials.username, password: credentials.password, } })

@carlobonamico#devoxxuk Saving the token In both cases, register a then() on the promise $http(...).then(function(response) { currentToken.jwt = response.data.access_token; } Store it locally If you need, parse it tokenPayload = jwtHelper.decodeToken(currentToken.jwt); date = jwtHelper.getTokenExpirationDate(currentToken.jwt); bool = jwtHelper.isTokenExpired(currentToken.jwt);

@carlobonamico#devoxxuk Integrating with angular-jwt Specify Token retrieval function angular.module('myApp') .config(function Config($httpProvider, jwtInterceptorProvider) { jwtInterceptorProvider.tokenGetter = ['currentToken', function(currentToken) { return currentToken.jwt; //or return localStorage.getItem('id_token'); }]; Register interceptor $httpProvider.interceptors.push('jwtInterceptor'); });

@carlobonamico#devoxxuk Back-end Login endpoint – validates credentials – generates JWT REST Service endpoints (or better interceptor) – extract Token from Authentication: header – validate it – proceed with request processing  or return error 401 Full example – http://thejackalofjavascript.com/architecting-a-restful-node-js-app/

@carlobonamico#devoxxuk JWT in... Plain Node: Auth0 library – https://github.com/auth0/node-jsonwebtoken Express: Express JWT – https://github.com/auth0/express-jwt Passport - Modular Auth Framework for node.js – http://passportjs.org/ .NET - OWIN.Identity – http://bitoftech.net/2014/10/27/json-web-token-asp-net-web-api-2- jwt-owin-authorization-server/ Java - Spring Security – https://spring.io/guides/tutorials/spring-security-and-angularjs/Integrating OAUTH with JWT

@carlobonamico#devoxxuk Were can we store / send the token? in a cookie? in a header?

@carlobonamico#devoxxuk Token Storage vs Session Duration In memory or sessionStorage – works only on current tab – automatically closed In localStorage – persistent – work across multiple tabs – requires explicit expiration https://stormpath.com/blog/where-to-store-your-jwts-cookies-vs- html5-web-storage/

@carlobonamico#devoxxuk Sending Tokens - Cookies vs Headers Cookies Pros – sent automatically – no code required on the client Cons – sent automatically – even when do not want  e.g. <IMG src= in email – less control on validity – stored on client disk Headers Pros – sent only explicitely – not stored on disk – unless you want to – more control – also prevents CSRF Cons – require code on the client side – but this is normal in SPAs https://auth0.com/blog/2014/01/27/ ten-things-you-should-know-about- tokens-and-cookies/

@carlobonamico#devoxxuk What else would we need? what happens when the user is not logged in? how to improve usability?

@carlobonamico#devoxxuk Routing support for Authentication & Authorization Need to configure Routing for – redirect to login if not authenticated – redirect to login if token expired – optionally, redirect back to original URL – redirect to error page if route not authorized in the current profile Difficult to do in the default ngRoute – Possible in ui-router Way easier in angular-new-router – https://medium.com/angularjs-meetup-south-london/angular-ng- conf-2015-media-25dbe6250154

@carlobonamico#devoxxuk A8-Cross-Site Request Forgery (CSRF)

@carlobonamico#devoxxuk CSRF See section “Security Considerations” on – https://docs.angularjs.org/api/ng/service/$http Angular automatically manages CSRF-prevention tokens if you use cookies The server needs to set a token – JavaScript readable session cookie called XSRF-TOKEN on the first HTTP GET request On subsequent XHR requests – the server can verify that the cookie matches X-XSRF-TOKEN HTTP header – the token must be unique for each user and must be verifiable by the server  e.g. a digest of your site's authentication cookie with a salt for added security Also, – Angular automatically supports JSONP-prevention characters  http://haacked.com/archive/2008/11/20/anatomy-of-a-subtle-json-vulnerability.as px/

@carlobonamico#devoxxuk A7-Missing Function Level Access Control

@carlobonamico#devoxxuk Typical Server side application Authorization is verified – in controllers if (user.hasRole(“admin”) == true) – through filters / interceptors – in views <hasRole role=”admin”> or <if (...)> confidential info </hasRole> Client Browser only receives content it has rights to – (roughly) works even if security checks are “spaghetti code” in the JSP/ASP/PHP templates

@carlobonamico#devoxxuk And in a SPA? Would this be secure? In users-view.html <button ngif=”authCtrl.isAdmin” ngclick=”userCtrl.deleteUser()”> or this? <section ngif=”authCtrl.isAdmin” > {{userCtrl.user.confidentialData}} </section>

@carlobonamico#devoxxuk No! Just press F12 and modify the HTML / JS or even the DOM in the developer tools

@carlobonamico#devoxxuk Security is up to the server Even in SPAs, Authorization is still up to the server: Security controls – checking authentication state – checking profile and inferring permissions – enabling privileged actions – filtering confidential data MUST be performed on the server – in the REST / websocket endpoints – locally in each service, or via filters/interceptors Also, the same rule applies to input validation

@carlobonamico#devoxxuk Usability is up to the client But letting the user click on the button, invoking the service, and only then displaying an error is not user friendly UX is up to the client – Front-End should have enough info to disable/hide the button  if the user is not authorized to click it  retrieve the permissions list from a REST service at logon E.g. Permission check directives for Angular <button ngclick=”postCtrl.delete()” haspermission=”deletePost”> permissions for Role-Based Access Control

@carlobonamico#devoxxuk Checking the user profile So, in each server endpoint, you should check – valid authentication – valid authorization profile which includes privileges for the currently requested action / data Example Blog application if (subject.hasRole(“admin”)) //enable delete post if (subject.hasRole(“editor”)) //enable modification of post else //only read data What are the problems with this code?

@carlobonamico#devoxxuk What if the rules change? What if an auditor asks about what an “editor” can do? Real-world cases tend to be more complex!

@carlobonamico#devoxxuk Role Based Access Control Separating Role definition from Permission check – In each service / action, code checks that the user has the relevant permission if (subject.hasPermission(“deletePost”)) – Role Definition lists all the permissions  e.g. –Admin detelePost, updatePost→ –anonymous readPost→ Authorization system maps user/groups to list of roles – and computes the “merged” set of permissions active for the valid user  user is both Admin & Editor  Permissions are –changeSettings, deleteUser, addUser, deletePost, modifyPost

@carlobonamico#devoxxuk Hierarchical permission system 2-level: User → Role → Permissions 3-level: User → Groups → Roles → Permissions Wildcard Permissions – blog:deletePost – blog:readPost – blog:* means both  blog:readPost:12 → entity level permission  blog:readPost:* on all entities see Apache Shiro

@carlobonamico#devoxxuk Advantages Permission check is – focused, readable – easy to implement – easy to test – rarely changes Role definition is – centralized – easy to review – easy to change – as it tends to change often Secure Design Principle all parts of the system need to perform security checks but security check implementation should be centralized and not “spread” in the system

@carlobonamico#devoxxuk RBAC in a Single Page Application Server-side Ingredients: – Profile definition mapping Roles to Permissions  static file  db table  possibly cached  Identity server (e.g. OpenAM) – API for checking permissions Normally, some of this information is cached to ensure minimal performance penalty

@carlobonamico#devoxxuk Usable Secure UI in AngularJS Ingredients: – /authorization/profile/current REST endpoint  returns a Json  current user roles  merged list of all active permissions On the Client – Client Service wrapping the above – Authorization/ProfileService storing the permission list  hasPermission(p) method Call the service from – Controller methods – Routing callbacks

@carlobonamico#devoxxuk Unvalidated Redirects

@carlobonamico#devoxxuk A9-Using Components with Known Vulnerabilities

@carlobonamico#devoxxuk Component Security The code we write The code which actually runs in our application – libraries and components

@carlobonamico#devoxxuk Checking dependecies for vulns On the client side – http://retirejs.github.io/retire.js/ npm install g retire ; retire –path src – also available as ZAP & mvn plugin mvn com.h3xstream.retirejs:retirejsmaven plugin:scan On the server side – OWASP Dependency Check  https://github.com/jeremylong/DependencyCheck dependencycheck.sh app Testing out . scan [path to jar files to be scanned] mvn org.owasp:dependencycheckmaven

@YourTwitterHandle#DVXFR14{session hashtag} @carlobonamico#devoxxuk A f nal w ord ... But isn't all that unnecessary complexity slowing down development of my critical project?

@carlobonamico#devoxxuk A final word People tend to view Security as “overhead”, not adding value to the project The reality: – if you know what to pay attention to, minimal additional costs – also, in most cases, adding security just means following good design principles if you separate well concerns, adding security is easy – favor clarity of intent and code readability – favor composition over inheritance – test, test, test!  incorporate security checks in your tests This lets software adapt more easily to both requirements & security changes – easier to evolve incrementally & validating each step → see Continuous Delivery

@carlobonamico#devoxxuk References

@carlobonamico#devoxxuk References Owasp Secure Coding Principles – https://www.owasp.org/index.php/Secure_Coding_Principles OWASP Testing Guide – https://www.owasp.org/index.php/OWASP_Testing_Guide_v4_Table_ of_Contents SOLID Design Principles – http://butunclebob.com/ArticleS.UncleBob.PrinciplesOfOod

@carlobonamico#devoxxuk HTML5 Security Attack Vectors & Vulnerabilities – https://media.blackhat.com/bh-eu-12/shah/bh-eu-12-Shah_HTML5_ Top_10-WP.pdf OWASP Guidelines – https://www.owasp.org/index.php/HTML5_Security_Cheat_Sheet JS Frameworks Security – http://www.slideshare.net/x00mario/jsmvcomfg-to-sternly-look-at- javascript-mvc-and-templating-frameworks

@carlobonamico#devoxxuk Thank You for your attention Interested? – attend our Web Application Security trainings – engage us for Design/Code Reviews, Vulnerability Assessments & team mentoring Read more on – http://www.nispro.it – http://www.slideshare.net/carlo.bonamico Follow us on twitter – @nis_srl @carlobonamico  updates on Security, AngularJS, Continuous Delivery Contact me – carlo.bonamico@gmail.com / carlo.bonamico@nispro.it

@YourTwitterHandle#DVXFR14{session hashtag} @carlobonamico#devoxxuk Q & A

Web Application Security Reloaded for the HTML5 era

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