May 14, 2005

Do not use the Atom Gmail service with online aggregators like Bloglines There is a real security threat     I study the problem of the secure web feeds since some weeks. I read a surprising post that talks about the Gmail Atom feed service used with Bloglines this morning. An idea came up in my mind while reading the post: it is not possible… can I really have access to login and password of people that subscribe to "secure" web feeds that use SSL and HTTP Authenticate with Bloglines? The answer is sadly: Yes I can.   The problem is that to use the Gmail Atom service in Bloglines, you need to build your feed's URL like this: https://USERNAME:PASSWORD@gmail.google.com/gmail/feed/atom, to provide the user and password to the feed's server.   All the problem is there: you have the username and the password in plaintext directly in the URL.   The first thing I then checked is if I was able to find such strings in online aggregators such as Bloglines. There is the answer:     Why do I have access to these URL? Probably because the Bloglines profile of these users are public and not private.   Then I tested if I was able to have access to these users and passwords by subscribing to the SSL and HTTP Authentication test feed on the silverorange project with Bloglines. I created two Bloglines profiles: one that the profile (Jim) and his blogroll are public and another (Todd) that will check the blogroll of the first account. The scenario goes like this:   Jim subscribes to a new SSL and HTTP Authentication protected feed with Bloglines. His profile is public and he does not know the consequences of what he is doing. The address he subscribe to is: https://testuser:testpass@secure3.silverorange.com/rsstest/ httpauth/rss_with_ssl_and_auth.xml   Todd discovers the public profile of Jim and checks his blogroll. He is lured by an entry called "Test Feed (HTTP Auth, SSL)" he checks it, likes it and subscribes to it. Then Todd see this Bloglines page:   Todd check more closely to this Bloglines page and remark:     Todd just discovered the user and password of a "secure" web feed. Basically he was not able to see the complete URL of the feed because it is viewable in the Bloglines system as: http://www.bloglines.com/preview?siteid=1830560. However, by subscribing to it, Bloglines shows the complete URL of the feed to the subscribed users.   This is just a test I performed with a SSL and HTTP Authentication RSS test feed available on silverorange.   Now, think about the consequences of this situation when users subscribe to Gmail or any other "secure" web feed using SSL and HTTP Authentication? The problem is real and could have many undesired consequences.   The best thing to do is not using such feeds in online services like Bloglines. Even in stand alone software it could be unsafe. I pointed out a week ago why I do not like this strategy to handle the problem of secure web feeds. This is a beautiful example of the potential problems it can lead to. You can read my article on the problem and the proposal of a solution here: Secure Web Feed Protocol.   This experience is a good example of the potential security treats that can appears when more than one system start to interact together.   Technorati Tags: [gmail] [atom] [Bloglines] [security] [feed] 5:17:54 PM        [comment []]    [trackback []]

New applications of the Secure Web Feed Protocol In Gmail and RSS Calendar     Five days ago I proposed my article: Secure Web Feed Protocol, to the PST05 conference. Two days after I came around 15 things you can do with RSS. Two of these applications got my attention:   Collect your email from all your email accounts in your RSS reader Stay updated on someone's schedule   I thought: these ideas are wonderful! What about the security of these services? Could they use SWFP? There is what I found.     1. Google is supposed to have tested a RSS feed service for Gmail in their GoogleLabs in 2004. I can not confirm if the service is always available because I do not have any Gmail accounts and I can not sing-in for one. This service put new incoming messages of a Gmail account into a RSS feed. Then if you subscribe to that feed you will see your new Gmail messages directly into your web feed reader. What an excellent idea! However, I was surprised to found that they used SSL to create a secure channel between the feed and the feed reader.   In the section 5 of the SWFP article I explained why I think that using SSL to secure a web feed is not the good strategy to adopt. It is for this reason that I was surprised to discover that they tried to use SSL to secure the inbox web feeds. JC suspected that they did not create it for this purpose but for another application called Google Notifier. I think he is right.   I do not know what was the real purpose of this test but the result is the same: the idea of using RSS feeds to check your mail is interesting. However, using SSL does not seem to be the good strategy to adopt. Not all stand alone feed readers support SSL. If you do not wish to enter the login and password of the private feed each time you want to check for new messages, you will need to do something like that:   https://USERNAME:PASSWORD@gmail.google.com/gmail/feed/atom   This solution is even worse than not encrypting the web feed at all. With this string an intruder could sing-in into your account then check, delete or send messages with your Gmail account. It is far worse than only having access to the unencrypted inbox content.   This is a beautiful idea that could be handled by the Secure Web Feed Protocol. Now check out the second application of RSS feed that could use SWFP.     2. This time we are sharing our calendar with our friends and family using a service called RSS Calendar. When you add something to it all your friends and family will have access to your calendar's changes. Is that not beautiful? Yeah it is. What about the security of this other service?   You could wish that the planet know that you are going to Mont Washington the 20 Mai 2005. But what if you only wish that your friends and family know it? There is no privacy feature in the service for the moment.   I think that the implementation of the Secure Web Feed Protocol could be really interesting in this case too. Only the people you choose would be able to read your calendar. I like the idea.     You are now thinking: how could the implementation of SWFP could be done in such services? The only thing that will change with what I discussed in the article is the way you will distribute the asymmetric keys Technorati Tags: [swfp] [secure] [web] [feed] [gmail] [rsscalendar] [rss] [atom] 11:04:26 AM        [comment []]    [trackback []]