Is AJAX A Security Risk? Probably--Get Over It

Asynchronous JavaScript and XML, the collection of programming technologies that promises to deliver online content to users without reloading an entire Web page, is back in the news. But this time, the news isn't good.

Forum Systems' VulCon XML security-alert service recently warned that AJAX could expose browsers to potential security problems. Because AJAX takes advantage of JavaScript to parse and execute commands on server data--and because those functions are visible right in the source of the page--there's real danger that client systems could come under attack.

Although a man-in-the-middle attack could exploit the basic workings of AJAX, it's more likely attackers would plant mean-spirited functionality on a server and then direct the client to it, resulting in the unintentional download of malicious code.

Web services opponents might view the flaw as yet another reason to stay away. But the problem isn't with Web services--it's with the client, which relies on the browser's scripting language. Unfortunately, there aren't many low-cost alternatives. Adobe is planning to freely distribute the SDK for its Flex 2.0 technology, which is more secure than a browser executing JavaScript, but Flex can be costly and time-consuming to deploy.

Is AJAX a security risk? Probably. But let's not drag Web services through the mud just because AJAX is one of today's most commonly used SOA clients.