Welcome!

Machine Learning Authors: Elizabeth White, William Schmarzo, Stackify Blog, Liz McMillan, Progress Blog

Related Topics: Machine Learning , Cloud Security

Machine Learning : Article

Application Security in AJAX

Mind the Gap

If you have evaluated AJAX (Asynchronous JavaScript and XML) for your next Web application development project, then you probably have read or heard a great deal about AJAX security concerns and the claim that AJAX increases the attack surface for hackers. If you are a skilled security developer, you might wonder whether the AJAX security problem originates in the technologies involved or whether lack of security in AJAX is a misconception. Security threats like SQL injection, cross-site scripting (XSS), message spoofing, and failed input validation existed before in Web applications and have been solved many times since then.

At first glance, it seems that the AJAX security discussion is a retelling of the tale of the emperor's new clothes. At second glance, however, it is obvious that there is a new component in AJAX security - the rich and interactive client. If this smart client really introduces a new security threat to Web applications, then the following questions arise: What can be done today, and what needs to be done in the future, to avoid ÒkillerÓ applications built with AJAX?

The Security Dilemma
Technology alone seldom is the problem. Lack of security in an application arises because of what developers do with the underlying technologies. To build secure Web applications - and this hasn't changed since traditional Web applications - there are two aspects of equal importance to be considered: humans and technology.

The most prevalent philosophy in application security is that security should not be added as an after thought, but should be included by design and default. The latter, however, never seems to happen in this feature-driven Internet technology industry, where new technologies are continuously being born. Two schools of thought exist in security: those who know everything and those who know next to nothing. It appears that because those who know everything are accustomed to handling the shortcomings of a given technology themselves, by devising workarounds or by using third-party security frameworks, it is up to those who know next to nothing to standardize security, making it a reachable goal for everyone.

AJAX is another example of putting security last and features first. AJAX is not a new technology. Instead, it consists of existing technologies such as JavaScript, Cascading Style Sheets (CSS), and Extensible Markup Language (XML) to implement Web 2.0 user interfaces. The technology used for dynamics in AJAX Web-user interfaces is JavaScript. This means, however, that the available Java security features, like the JavaScript sandbox and the same origin policy, are the main security features available in AJAX.

•  Same Origin Policy: The same origin policy prevents scripts that are downloaded from a Website to access properties on a page that is downloaded from another Website. The security of the same origin policy, which ensures that malicious scripts do not hijack other loaded documents or spy on user cookies or key inputs, conflicts with another Web 2.0 wanted functionality: mashup. A mashup is an application page that consumes mixed services to build a composite Web-user interface. This type of application may need to interoperate between page fragments, even if it is downloaded from different servers and domains. Within the AJAX community and the World Wide Web Consortium (W3C), a desire exists to loosen the same origin policy limitation for XMLHttpRequest object (XHR) requests, which, from a security perspective, would require trusted clients that do not exist today.
•  JavaScript Sandbox: JavaScript is contained in the browser execution environment and is not allowed to access either the client file system or the network, except through Hypertext Transfer Protocol (HTTP) requests. All that JavaScript has access to is the memory representation of the displayed browser document, called the document object model (DOM).

In JavaScript, little can be hidden from would-be hackers because all facets within a page are accessible and modifiable in the DOM tree. Exposing JavaScript source on the client, where it can be read or stolen, is not a security problem. If it were, open source software, which does not hide its implementation from viewers, would pose a huge security threat.

Client-side sources are problematic because everything is accessible in the DOM, which means that nothing can be protected on the client. Any security policy that is downloaded and enforced on the client can be read and manipulated. Obscurity is not a substitute for security. In fact, obfuscated JavaScript only helps to lock out wannabe hackers and is otherwise primarily used to increase JavaScript performance through reduced content lengths.

Where AJAX Fits in an MVC Architecture
Modern Web applications that implement the model view controller (MVC) pattern demand a separation of the application presentation from its life cycle and model. AJAX is a presentation layer technology that is used to render interactive Web-user interfaces in rich Internet applications (RIA). As an application developer, you don't write end-to-end business applications in AJAX. Instead, you use a server-side technology to handle the business logic. One of the niceties of AJAX is that it is independent of the server technology business layer. Therefore, AJAX works the same with Java, C, Perl, PLSQL, and .NET back ends. This clean separation between the presentation and business layers is a choice that every application developer should consider. Security should be implemented end-to-end, which means that all parts of the application should follow the same policy and share the same user security context. This also includes database security if databases are involved.

Security in AJAX
Unlike traditional Web applications that have a more or less static user interface, AJAX applications have an active client that uses the browser's native XHR to fetch data from a server. There are two major risks to the browser regarding client-side JavaScript: browser bombing and cross-site scripting attacks:
•  Browser bombing is the client version of a denial of service (DoS) attack. During this type of attack, the client is kept busy with JavaScript processing, such as running endless loops that fill up an array with content. When the client consumes all computing resources, the desktop hangs.
•  Cross-site scripting has two facets. The first one, which was already mentioned, is where a script downloaded from one domain tries to access properties of a page downloaded from another domain. The second facet is where developers fail to validate user input, resulting in a JavaScript that is executed when the user-added input is rendered on a Web page. Imagine a discussion forum that does not encode JavaScript content or check for SQL keywords. A hacker could, for instance, add JavaScript that performs a runtime attachment of an image tag to the page in which the src attribute references a uniform resource locator (URL) on the hacker's server. The script could, for example, append the client's cookies as a request parameter. The application user does not recognize these changes because the HTML does not flag a missing image as an error.

While client-side security protects the end user from the application, application security protects the application from the user. Protection includes enforcement of authentication, authorization, and data privacy.

Though XSS and SQL injection attacks can be handled in AJAX on the client, you should not miss the opportunity to enforce the same policy on the back end in an additional layer of defense. In traditional Web applications, request filters implemented on the HTTP server (or in the application configuration) performed pattern searches using such things as Regular Expressions on the incoming request to detect technology keywords of JavaScript and SQL. In addition, filters were used to replace special characters with their encoded equivalent, such as when replacing < with <. AJAX applications are like traditional Web applications, so the same security design patterns apply to them.

Security design patterns are recommendations of best practices to mitigate the risk of an identified threat. Patterns that exist for Web applications include defense in depth, limited view, least privileged access, checkpoint, and roles.

In addition to best security practices, there exists a sensitive balance between usability, performance, and security that needs to be considered when building AJAX applications. It is easy to risk vulnerabilities simply by annoying end users with too many security-related interruptions when they are working in an application. Such users soon turn into hackers on their mission to find a more convenient way to work with an application. AJAX applications are based on client-side JavaScript and only provide a minimum capability to maintain client-state in cookies and page variables. Unless the AJAX application is built on top of a server-side framework that manages the application state, AJAX applications risk losing state upon page reload and navigation, adding a need to re-request user security credentials.


More Stories By Frank Nimphius

Frank Nimphius is a principal product manager for application development tools at Oracle Corporation. As a conference speaker, Frank represents the Oracle J2EE development team at J2EE conferences world wide, including various Oracle user groups and the Oracle Open World conference.

Comments (1) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Most Recent Comments
navot 10/08/07 04:14:59 AM EDT

I would like to draw your attention to another alternative which is a paradigm shift for AJAX front ends. One should be aware that I am not, and do not pretend to be objective, never the less I believe that one can judge for himself. Visual WebGui is an AJAX frame work that doesn’t expose logic, data or open services on client requests and therefore is not as vulnerable as common AJAX solution. Worth a look at www.visualwebgui.com.

@CloudExpo Stories
"Cloud Academy is an enterprise training platform for the cloud, specifically public clouds. We offer guided learning experiences on AWS, Azure, Google Cloud and all the surrounding methodologies and technologies that you need to know and your teams need to know in order to leverage the full benefits of the cloud," explained Alex Brower, VP of Marketing at Cloud Academy, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clar...
In his session at 21st Cloud Expo, Carl J. Levine, Senior Technical Evangelist for NS1, will objectively discuss how DNS is used to solve Digital Transformation challenges in large SaaS applications, CDNs, AdTech platforms, and other demanding use cases. Carl J. Levine is the Senior Technical Evangelist for NS1. A veteran of the Internet Infrastructure space, he has over a decade of experience with startups, networking protocols and Internet infrastructure, combined with the unique ability to it...
While some developers care passionately about how data centers and clouds are architected, for most, it is only the end result that matters. To the majority of companies, technology exists to solve a business problem, and only delivers value when it is solving that problem. 2017 brings the mainstream adoption of containers for production workloads. In his session at 21st Cloud Expo, Ben McCormack, VP of Operations at Evernote, discussed how data centers of the future will be managed, how the p...
"NetApp is known as a data management leader but we do a lot more than just data management on-prem with the data centers of our customers. We're also big in the hybrid cloud," explained Wes Talbert, Principal Architect at NetApp, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
"We're focused on how to get some of the attributes that you would expect from an Amazon, Azure, Google, and doing that on-prem. We believe today that you can actually get those types of things done with certain architectures available in the market today," explained Steve Conner, VP of Sales at Cloudistics, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
"Space Monkey by Vivent Smart Home is a product that is a distributed cloud-based edge storage network. Vivent Smart Home, our parent company, is a smart home provider that places a lot of hard drives across homes in North America," explained JT Olds, Director of Engineering, and Brandon Crowfeather, Product Manager, at Vivint Smart Home, in this SYS-CON.tv interview at @ThingsExpo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
It is of utmost importance for the future success of WebRTC to ensure that interoperability is operational between web browsers and any WebRTC-compliant client. To be guaranteed as operational and effective, interoperability must be tested extensively by establishing WebRTC data and media connections between different web browsers running on different devices and operating systems. In his session at WebRTC Summit at @ThingsExpo, Dr. Alex Gouaillard, CEO and Founder of CoSMo Software, presented ...
Enterprises are adopting Kubernetes to accelerate the development and the delivery of cloud-native applications. However, sharing a Kubernetes cluster between members of the same team can be challenging. And, sharing clusters across multiple teams is even harder. Kubernetes offers several constructs to help implement segmentation and isolation. However, these primitives can be complex to understand and apply. As a result, it’s becoming common for enterprises to end up with several clusters. Thi...
"There's plenty of bandwidth out there but it's never in the right place. So what Cedexis does is uses data to work out the best pathways to get data from the origin to the person who wants to get it," explained Simon Jones, Evangelist and Head of Marketing at Cedexis, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
WebRTC is great technology to build your own communication tools. It will be even more exciting experience it with advanced devices, such as a 360 Camera, 360 microphone, and a depth sensor camera. In his session at @ThingsExpo, Masashi Ganeko, a manager at INFOCOM Corporation, introduced two experimental projects from his team and what they learned from them. "Shotoku Tamago" uses the robot audition software HARK to track speakers in 360 video of a remote party. "Virtual Teleport" uses a multip...
"We work around really protecting the confidentiality of information, and by doing so we've developed implementations of encryption through a patented process that is known as superencipherment," explained Richard Blech, CEO of Secure Channels Inc., in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
High-velocity engineering teams are applying not only continuous delivery processes, but also lessons in experimentation from established leaders like Amazon, Netflix, and Facebook. These companies have made experimentation a foundation for their release processes, allowing them to try out major feature releases and redesigns within smaller groups before making them broadly available. In his session at 21st Cloud Expo, Brian Lucas, Senior Staff Engineer at Optimizely, discussed how by using ne...
The question before companies today is not whether to become intelligent, it’s a question of how and how fast. The key is to adopt and deploy an intelligent application strategy while simultaneously preparing to scale that intelligence. In her session at 21st Cloud Expo, Sangeeta Chakraborty, Chief Customer Officer at Ayasdi, provided a tactical framework to become a truly intelligent enterprise, including how to identify the right applications for AI, how to build a Center of Excellence to oper...
"IBM is really all in on blockchain. We take a look at sort of the history of blockchain ledger technologies. It started out with bitcoin, Ethereum, and IBM evaluated these particular blockchain technologies and found they were anonymous and permissionless and that many companies were looking for permissioned blockchain," stated René Bostic, Technical VP of the IBM Cloud Unit in North America, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Conventi...
In his session at 21st Cloud Expo, James Henry, Co-CEO/CTO of Calgary Scientific Inc., introduced you to the challenges, solutions and benefits of training AI systems to solve visual problems with an emphasis on improving AIs with continuous training in the field. He explored applications in several industries and discussed technologies that allow the deployment of advanced visualization solutions to the cloud.
Gemini is Yahoo’s native and search advertising platform. To ensure the quality of a complex distributed system that spans multiple products and components and across various desktop websites and mobile app and web experiences – both Yahoo owned and operated and third-party syndication (supply), with complex interaction with more than a billion users and numerous advertisers globally (demand) – it becomes imperative to automate a set of end-to-end tests 24x7 to detect bugs and regression. In th...
SYS-CON Events announced today that Telecom Reseller has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.
"We're developing a software that is based on the cloud environment and we are providing those services to corporations and the general public," explained Seungmin Kim, CEO/CTO of SM Systems Inc., in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
Enterprises are moving to the cloud faster than most of us in security expected. CIOs are going from 0 to 100 in cloud adoption and leaving security teams in the dust. Once cloud is part of an enterprise stack, it’s unclear who has responsibility for the protection of applications, services, and data. When cloud breaches occur, whether active compromise or a publicly accessible database, the blame must fall on both service providers and users. In his session at 21st Cloud Expo, Ben Johnson, C...
SYS-CON Events announced today that CrowdReviews.com has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5–7, 2018, at the Javits Center in New York City, NY. CrowdReviews.com is a transparent online platform for determining which products and services are the best based on the opinion of the crowd. The crowd consists of Internet users that have experienced products and services first-hand and have an interest in letting other potential buye...