Welcome!

You will be redirected in 30 seconds or close now.

ColdFusion Authors: Yakov Fain, Jeremy Geelan, Maureen O'Gara, Nancy Y. Nee, Tad Anderson

Related Topics: ColdFusion

ColdFusion: Article

Implementing HTTP Basic Authentication

Route around many of the common limitations of traditional forms-based authentication

How to Implement Basic Authentication with ColdFusion
The first time a Web browser requests a page that's protected by Basic authentication, the Web server needs a way to tell it that it should stop and ask the user for login information. It does this by sending a response to the initial request with the status code 401 ("Access Denied"). In this response, it also sends information about what types of authentication it's willing to accept (this is the "WWW-Authenticate" header). In this article, we're only discussing Basic Authentication, but other more complex (and more secure) methods exist such as Digest authentication and Microsoft's proprietary NTLM authentication. Along with the 401 response the server also sends a user-friendly (or at least user-readable) explanation of why access is being denied.

When the browser gets the 401 response, before showing the user the "Access Denied" message, it prompts for a user name and password. If the user provides credentials, the browser repeats the request and includes the user name and password in an "Authorization" request header. If the credentials are sufficient, the server then sends the requested page with a 200 ("OK") status code. If the credentials aren't acceptable to the server, it simply sends back the same 401 response, which makes the browser prompt the user again. If the user declines to provide credentials (by clicking a "Cancel" button on the password prompt, for example), or fails to provide acceptable credentials a certain number of times (usually three, although it's up to the Web browser to decide), the browser stops prompting the user and shows the user the "Access Denied" message provided by the server.

Listing 1 shows the code needed to implement Basic Authentication. This code should be included at the top of any page that needs to be protected by authentication (an Application.cfm file is a good place, for example).

The first lines use the built-in ColdFusion function GetHttpRequestData() to retrieve complete information on the request headers sent by the client and ensure that our session-level user variable is initialized. Then the code checks to see if the client has provided the "Authorization" header that contains the login and password. The "Authorization" header consists of two parts separated by a single space: first, the authentication scheme (in this case "Basic"); and second, the user name and password separated by a colon and Base64-encoded to protect them from character set issues during transmission. The user name and password are decoded using the ToBinary() and ToString() functions, and the application verifies that they're correct (obviously this part will vary from application to application). If the user hasn't been logged in either by providing incorrect credentials or by not providing any at all, the response code is set to 401 and the "WWW-Authenticate" response header is added. Finally, a user-friendly "Access Denied" message is added to the response and execution is stopped so the server sends only the "Access Denied" message back to the client.

Even if the user has cookies disabled, so the user's session doesn't persist from request to request, the user won't be prompted again for a login and password. However, in this case, you won't be able to store any other data in the session scope without resorting to passing session identifiers as URL parameters.

Since the browser is getting accurate response codes throughout the transaction, there's no need to write code to redirect the user after a successful login. This is an additional benefit of using Basic authentication and means that your application fully supports deep linking and bookmarking without any extra code.

The Authentication Realm
There's one additional piece of information that the server sends in the "WWW-Authenticate" header: the authentication realm. The realm is defined as a string that uniquely identifies the set of resources on the server that all use the same user account source. The browser assumes that if it has prompted the user for a login and password for a resource on a given server, it can reuse the same credentials for another resource in the same realm on the same server.

Although the specification for Basic authentication discourages the use of the realm for any purpose other than matching it for equality against other realm values, in practice the realm actually has another important function. When most browsers prompt the user for login credentials, they show the realm as a description of the application the user is logging in to. So it's a good idea to set the realm in your authentication code to a brief description of your application (this description would replace the string "MyApplication" in Listing 1).

Caching of Credentials: The End of Session Expiration
When a browser gets a 401 ("Access Denied") message in response to a request for a given resource, it checks to see if the realm specified in the "WWW-Authenticate" header matches any realms it has already authenticated against on the current server for the current browser session. If it finds credentials that have been accepted for that realm, it retries the request using those credentials (prompting the user for credentials only if the cached credentials are rejected by the server). The browser also assumes that resources in subdirectories below the resources for which it has already been prompted to authenticate will be part of the same realm and preemptively sends the cached credentials the first time it requests these resources. These two facts contribute to one of the biggest advantages of Basic authentication: the end of session expiration messages.

Examine Listing 1 again and consider what happens if the user has been previously authenticated but has been inactive enough that the session expired. On the next request, a new session is initiated by the ColdFusion server and SESSION.loggedInUserName is set to an empty string. If the browser has previously requested the page, it will have preemptively sent the login credentials; if not, it will check its cache and see that it already has credentials for the specified realm and it will repeat the request, providing the cached credentials. In either case, the user has been automatically logged back into the application without being prompted! This provides a much smoother and less confusing experience for the user.

Keep in mind that this may have some affect on your application architecture. If you're using the session scope only to cache information that's already stored in a database somewhere, your application can probably be converted to Basic authentication with no issues. However, if you store temporary data in the session scope (such as shopping cart information), you may have to consider a different approach since the user may have multiple ColdFusion sessions over the course of what they consider a single session of interacting with the Web application. Just remember that a user session might be initialized on any page of your application.

Limitations of Basic Authentication
Basic authentication isn't without its limitations. First and foremost, it's important to realize that the user name and password is transmitted from the browser to the Web server in unencrypted clear text. (The Base64 encoding isn't a security measure - it's designed to be easily reversible.) If you consider the data in your application to be sensitive, you should definitely use an additional security layer such as SSL to protect the transmission of the user name and password (as well as the data). That being said, this lack of encryption is a limitation that's common to both forms-based and Basic authentication.

The other significant limitation of Basic authentication, and the only major drawback to using it over forms-based authentication, is that it provides much less opportunity for context around the login and password. A forms-based solution can show information around the login box explaining the format of the login and, in the case of password errors, can provide detailed information about what went wrong. Additionally, the login prompt can be customized to match the look-and-feel of the rest of the application. When implementing HTTP Basic authentication, you should provide an entry page that isn't authenticated that provides this information so the user is prepared to enter the appropriate login and password information.

Conclusion
Basic authentication provides an alternative to traditional forms-based authentication methods. By sticking closely to the HTTP specification, this method leverages features built in to the Web browser to prevent confusing session expiration problems and the need to code around other limitations in non-standard forms-based authentication methods.

More Stories By Patrick Correia

Patrick Correia is a Web developer for Clough Harbour & Associates LLP, an east coast multi-disciplined engineering firm. A Certified Advanced ColdFusion MX Developer based in Albany, New York, he has spent the last five years developing ColdFusion-based business process improvement solutions for the firm's numerous municipal and private clients.

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
MikeR 06/08/06 11:43:56 PM EDT

Interesting article but it failed to mention the huge flaw with basic auth.

Basic authentication can't be used for most real-world sites because:
(1) There is now way for the user to log out short of closing all browser windows.
and (2) There is no practical way for the site to logout or timeout a user.

@ThingsExpo Stories
If you’re responsible for an application that depends on the data or functionality of various IoT endpoints – either sensors or devices – your brand reputation depends on the security, reliability, and compliance of its many integrated parts. If your application fails to deliver the expected business results, your customers and partners won't care if that failure stems from the code you developed or from a component that you integrated. What can you do to ensure that the endpoints work as expect...
So, you bought into the current machine learning craze and went on to collect millions/billions of records from this promising new data source. Now, what do you do with them? Too often, the abundance of data quickly turns into an abundance of problems. How do you extract that "magic essence" from your data without falling into the common pitfalls? In her session at @ThingsExpo, Natalia Ponomareva, Software Engineer at Google, provided tips on how to be successful in large scale machine learning...
In his general session at 18th Cloud Expo, Lee Atchison, Principal Cloud Architect and Advocate at New Relic, discussed cloud as a ‘better data center’ and how it adds new capacity (faster) and improves application availability (redundancy). The cloud is a ‘Dynamic Tool for Dynamic Apps’ and resource allocation is an integral part of your application architecture, so use only the resources you need and allocate /de-allocate resources on the fly.
If you had a chance to enter on the ground level of the largest e-commerce market in the world – would you? China is the world’s most populated country with the second largest economy and the world’s fastest growing market. It is estimated that by 2018 the Chinese market will be reaching over $30 billion in gaming revenue alone. Admittedly for a foreign company, doing business in China can be challenging. Often changing laws, administrative regulations and the often inscrutable Chinese Interne...
Enterprise IT has been in the era of Hybrid Cloud for some time now. But it seems most conversations about Hybrid are focused on integrating AWS, Microsoft Azure, or Google ECM into existing on-premises systems. Where is all the Private Cloud? What do technology providers need to do to make their offerings more compelling? How should enterprise IT executives and buyers define their focus, needs, and roadmap, and communicate that clearly to the providers?
Complete Internet of Things (IoT) embedded device security is not just about the device but involves the entire product’s identity, data and control integrity, and services traversing the cloud. A device can no longer be looked at as an island; it is a part of a system. In fact, given the cross-domain interactions enabled by IoT it could be a part of many systems. Also, depending on where the device is deployed, for example, in the office building versus a factory floor or oil field, security ha...
SYS-CON Events announced today that Commvault, a global leader in enterprise data protection and information management, has been named “Bronze Sponsor” of SYS-CON's 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Commvault is a leading provider of data protection and information management solutions, helping companies worldwide activate their data to drive more value and business insight and to transform moder...
The many IoT deployments around the world are busy integrating smart devices and sensors into their enterprise IT infrastructures. Yet all of this technology – and there are an amazing number of choices – is of no use without the software to gather, communicate, and analyze the new data flows. Without software, there is no IT. In this power panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, panelists will look at the protocols that communicate data and the emerging data analy...
Digital innovation is the next big wave of business transformation based on digital technologies of which IoT and Big Data are key components, For example: Business boundary innovation is a challenge to excavate third-party business value using IoT and BigData, like Nest Business structure innovation may propose re-building business structure from scratch, as Uber does in the taxicab industry The social model innovation is also a big challenge to the new social architecture with the design fr...
Fifty billion connected devices and still no winning protocols standards. HTTP, WebSockets, MQTT, and CoAP seem to be leading in the IoT protocol race at the moment but many more protocols are getting introduced on a regular basis. Each protocol has its pros and cons depending on the nature of the communications. Does there really need to be only one protocol to rule them all? Of course not. In his session at @ThingsExpo, Chris Matthieu, co-founder and CTO of Octoblu, walk you through how Oct...
Is your aging software platform suffering from technical debt while the market changes and demands new solutions at a faster clip? It’s a bold move, but you might consider walking away from your core platform and starting fresh. ReadyTalk did exactly that. In his General Session at 19th Cloud Expo, Michael Chambliss, Head of Engineering at ReadyTalk, will discuss why and how ReadyTalk diverted from healthy revenue and over a decade of audio conferencing product development to start an innovati...
Data is an unusual currency; it is not restricted by the same transactional limitations as money or people. In fact, the more that you leverage your data across multiple business use cases, the more valuable it becomes to the organization. And the same can be said about the organization’s analytics. In his session at 19th Cloud Expo, Bill Schmarzo, CTO for the Big Data Practice at EMC, will introduce a methodology for capturing, enriching and sharing data (and analytics) across the organizati...
There is little doubt that Big Data solutions will have an increasing role in the Enterprise IT mainstream over time. Big Data at Cloud Expo - to be held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA - has announced its Call for Papers is open. Cloud computing is being adopted in one form or another by 94% of enterprises today. Tens of billions of new devices are being connected to The Internet of Things. And Big Data is driving this bus. An exponential increase is...
IoT is fundamentally transforming the auto industry, turning the vehicle into a hub for connected services, including safety, infotainment and usage-based insurance. Auto manufacturers – and businesses across all verticals – have built an entire ecosystem around the Connected Car, creating new customer touch points and revenue streams. In his session at @ThingsExpo, Macario Namie, Head of IoT Strategy at Cisco Jasper, will share real-world examples of how IoT transforms the car from a static p...
Internet of @ThingsExpo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with the 19th International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world and ThingsExpo Silicon Valley Call for Papers is now open.
SYS-CON Events has announced today that Roger Strukhoff has been named conference chair of Cloud Expo and @ThingsExpo 2016 Silicon Valley. The 19th Cloud Expo and 6th @ThingsExpo will take place on November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. "The Internet of Things brings trillions of dollars of opportunity to developers and enterprise IT, no matter how you measure it," stated Roger Strukhoff. "More importantly, it leverages the power of devices and the Interne...
"My role is working with customers, helping them go through this digital transformation. I spend a lot of time talking to banks, big industries, manufacturers working through how they are integrating and transforming their IT platforms and moving them forward," explained William Morrish, General Manager Product Sales at Interoute, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Video experiences should be unique and exciting! But that doesn’t mean you need to patch all the pieces yourself. Users demand rich and engaging experiences and new ways to connect with you. But creating robust video applications at scale can be complicated, time-consuming and expensive. In his session at @ThingsExpo, Zohar Babin, Vice President of Platform, Ecosystem and Community at Kaltura, will discuss how VPaaS enables you to move fast, creating scalable video experiences that reach your...
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life sett...
SYS-CON Events announced today that China Unicom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. China United Network Communications Group Co. Ltd ("China Unicom") was officially established in 2009 on the basis of the merger of former China Netcom and former China Unicom. China Unicom mainly operates a full range of telecommunications services including mobile broadband (GSM, WCDMA, LTE F...