It is just a matter of time. One of these days, some hacker will deface a popular site like Engadget. But instead of putting something visible on the site, they will put something invisible in the feed.
By the magic of syndication, that data will then be distributed like spores to untold thousands of locations. In the process it will be transported from a relatively untrusted location (like BoingBoing) to a place of equal or greater trust. Places like popular portal sites, or just perhaps, to your very own hard drive.
From there, it will lie in wait until you check for news. Invisibly it will spring into action. You won’t even notice it running. It will be able to do things that vary from uploading your preferences and passwords to a remote location, to downloading malware onto your machine. Shortly thereafter, this entry will be marked as read, or scroll off the bottom of your river of news, and you will never know how you just got p0wned.
Sometime in November (i.e., in about 90 days), and with James’s consent, I will commit these tests as a part of the Feed Parser regression test suite. At which point, they will be open source, and easy to find by friend and foe alike.
Meanwhile, if you are developing software that consumes feeds, please get ahold of either James or myself and we will share these tests with you. Contributions of additional tests are also welcome.