Facebook Platform Privacy Issues

For the record, Facebook has some of the most flexible and robust privacy controls I’ve seen in any online social networking service. I never want to take for granted that Facebook engineers have built remarkable privacy controls into their product, and for that they should be rightly commended.

But unfortunately, since launching the Facebook Platform, the company has unwittingly introduced several privacy problems inherent in the platform’s structure. These issues are not without solutions, yet so far Facebook’s management does not appear to view them as serious or worth the time to fix. In this article, I intend to summarize four specific problems that I believe deserve a second look.

Problem #1: One Access Level

If an application retrieves user data, a user must give it full access. A review of the top 150 Facebook applications in October 2007 found that nearly 91% had access to unnecessary private data. Given the recreational nature of many top applications today, this statistic has probably not changed drastically. Users have become accustomed to authorizing even simple applications and do not know what data will be used prior to authorizing an application. Rogue applications can thus harness a wealth of user data, and even legitimate applications can misuse data or allow potential misuse. Solutions include privacy-by-proxy for FBML applications and offering tiers of data access. With the latter, users could be prompted more specifically for authorizing data beyond basic information.

Problem #2: Single-Click Authorization

Not only do users allow applications access to a wealth of data on authorization, this action only requires one click on a button when an application page is first accessed. This opens the door to clickjacking attacks, similar to attacks launched against Twitter users earlier this year. A user could click a seemingly innocent link that authorizes a rogue application. Solutions include code for detecting possible clickjacking, such as framebusting, and requiring additional interaction, such as a prompt.

Problem #3: External Script Access

Facebook has taken admirable steps to limit code within an application that originates outside the application’s hosted domain. However, external JavaScript can not only access data within the application but can also make requests for additional user data. As an example, one major application ad program requires developers to add an HTML file to their application’s domain and include the file as an inline frame within the application. This file then calls external JavaScript that makes API calls to Facebook using the session information passed from the application to the frame. This problem is admittedly more difficult to solve, but perhaps better educating developers and advertisers on safer code techniques would be a starting point.

Problem #4: Secondary Code Vulnerabilities

Since every application has full access to user data, any code vulnerability in an application becomes a security problem for Facebook itself. For instance, a recently uncovered cross-site scripting vulnerability in an application allows a malicious hacker to access a user’s profile data if they simply access a specially crafted URI. By giving applications access to user data, Facebook and its users trust third-party developers to build applications secure enough for handling personal information. Unfortunately, many developers overlook basic security measures. Once again, this issue can be thorny, but solving it starts with educating developers. Also, offering tiers of data access for an application could limit the impact of vulnerabilities in applications that only require basic information.

Conclusion

I personally have not witnessed any major concern or forthcoming solutions to these problems from Facebook, despite security researchers noting them for some time. I have already seen these flaws used in previous attacks on Facebook, and I can foresee them being used in future attacks of significant severity.

Addressing these issues, however, begins with awareness. Users need to better understand the ramifications of platform use and need to learn better habits for using applications. Developers need to better understand proper coding practices and help protect user data. Advertisers need to avoid using personally identifiable information and clarify how they target users.

Most importantly, though, I believe that Facebook needs to adjust their platform to continue their track record of respecting user privacy. But it appears this will only happen if Facebook users realize the severity of the situation and ask for a change.

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SuperPoke XSS Vulnerability

This morning I randomly came across an old article on Inside Facebook that quoted yours truly on application security.  In the quote, I described injecting FBML into applications via a query string, though I also noted that I was unsure how serious such an attack could be.  One of the applications I had in mind was SuperPoke.  Since the Inside Facebook article was published in February of last year, I decided to check SuperPoke once again.

To my shock, not only had the hole not been fixed, it was worse.  SuperPoke is now loaded as an iframe instead of an FBML canvas page, and the injection method still works fine.  That means one can now use it to inject arbitrary HTML into the SuperPoke iframe.  Using this, a malicious coder could easily insert JavaScript (and set or modify cookies) into the page (XSS).

Normally this is serious, but in a Facebook application, it’s even worse.  Since the script would be embedded in an application iframe, it would be able to make FQL queries using the application’s session information, just as I previously discussed SocialReach and SocialCash doing.  In fact, such script could probably use just about anything in the JS API.  I’ve already tested building URLs for FQL queries via the REST API.

Did I mention that SuperPoke is a Facebook Verified Application?

Granted, this type of attack requires a user to make a click, but any security researcher knows that’s not difficult.  And since the JavaScript loads silently, the user would only see a normal SuperPoke page appear and not realize anything was amiss.  As always, e-mail for details.  I thought it would not be wise to release details publicly given the significance of this attack, though as usual they’re not that hard to figure out.

Update (6/19): I’ve put together some proof-of-concept code that exploits this XSS vulnerability.  Loading a particular SuperPoke URI executes a remote script which then retrieves user data via the Facebook API.  The API call to Facebook appears to come from the application page.  Details available upon request.

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Attacking Password Resets w/ Social Networks

Posted originally on Neohaxor.org, re-posted with permission:


Password Reset: Your passport to a fuxored account.

Password Reset Methods Vulnerable? Really? Get out of here, you mean that many password reset methods are vulnerable to attack? You have to be kidding. The fact that people think vulnerable password reset is newsworthy have got to be crazy. This is something that many of us have been talking about for years. Now Sarah Palin’s email gets attacked and it is big deal. It amazes me why we always wait to get screwed by something before we fix it.

Why does everything in the security world have to be a response to something. Ok, not the security world but the business security world. They are definitely two different entities. I am truly tired of reactive security. Just think if other professions followed this reactive model, like a cop asking for a bullet proof vest after they have already been shot. Nobody can say they didn’t see this coming either. People make more of their life known through social networks, photo sharing, and blogs than ever before. The simple password reset questions just don’t hold up.

There is a lot of unnecessary fear about data from social networks being used to steal someone’s identity. Although this is mostly FUD, social networks can be a great source for password recovery data. A while back we recovered a password (with his permission of course) from my friend Brian’s Sprint account using data from his MySpace page. This is when we were first starting our research for the social network hacking project.

Let’s take a step back from social networks for a sec, would your friends, co-workers, significant other, etc. be able to recover your password with the information they know about you? If the answer to that question is yes, then you need to change something. Passwords should be something that you know, not you and a couple of other people.

What Types of Data are on Social Networks?

The information that people put on their social network pages range from minimal to wildly over the top. Some people even go above and beyond by posting survey questions that tell a lot about their personalities. Although they want to show off the depth of their personality, all it really does is show off the shallowness of their brain.

Social networks by their default nature basically allow you to “friend” the world. The information on people’s social network page typically contains information that was previously only known to traditional friends and acquaintances. This can be a huge problem for the password reset mechanism, not to mention a person’s privacy. If it’s deep and kinda scary from a privacy standpoint then it is probably on a social network. Remember when I mentioned if your friends knew enough about you to reset your password then you are in trouble, well you just friended the world with the information from your social network profile. Beyond standard profile information there are a users actions taken on a social network site and possibly social network applications that are being used as well. All of this information can be leveraged when attacking a password reset mechanisms.

You can use an email address to look up people’s accounts on social networking sites. On the flip side, someone social network profile might directly tell you a person’s email address or you can use the search features of the social network to query owner’s of certain email addresses. There are no secrets in social networking ;)

Email Accounts are Gold

With password resets an email account is really the jackpot. Many password reset mechanisms, including the ones from social networks, rely on sending either the password or a temporary password to the email address of the account owner. Someone who gets their email account compromised might just find that they have every other account tied to that email account compromised as well. I mean, it wouldn’t be a far stretch to figure that out once someone had access to the email account. Just think of all the crap that sites like Amazon, eBay, MySpace, Facebook, etc. send to your email account.

Typical Password Questions

Typical password recovery questions really vary in complexity from site to site. What is the problem with password recovery questions in general? Well, they are not typically made up of data that is private. Unlike a password which is supposed to be something that only you know, recovery questions may be known to many people around you.

Here are some questions from Yahoo:

  • Where did you meet your spouse?
  • What was the name of your first school?
  • Who was your childhood hero?
  • What is your favorite pastime?
  • What is your favorite sports team?
  • What is your father’s middle name?
  • What was your hight school mascot?
  • What make was your first car or bike?
  • What is your pets name?

Some of these questions look like questions that social networks ask when you are filling out a profile, don’t they? If not questions they ask, certainly data that people put on their social network profiles or divulge through other means on a social network.

The Obvious

Take a glance at someone’s profile or maybe your profile on a social network. From just this page without further probing there may be an enormous amount of information. Depending on the mechanism that is being attacked, it may be all that is needed. Here is an example of some of the things that may be found just on the profile page:

  • Name
  • Date of Birth
  • Hometown
  • Current town
  • Favorite movies, artists, music, people, TV, sports teams, etc
  • High School
  • College
  • Personal description
  • Personality traits
  • Networks and Groups
  • Relationship information
  • Family information
  • Employer

The list really goes on and on. Remember that many people are on multiple social networks. Checking out other social networks may fill in the blanks. It is easy to see why this information could be a problem and I don’t think it needs any further explanation.

The Not So Obvious

Some data is not so obvious and might not be directly spelled out. This may be information that has to be aggregated or inferred from the profile data, friends list, blog, group, network, etc.

  • Photos and photo tags
  • Comments on other profiles
  • Photo data (cloths, background, other individuals, etc)
  • Pets
  • Children
  • Siblings
  • Relatives (potentially ones with your mother’s maiden name?)
  • Potential usernames
  • Instant messenger data
  • Blogs and comments in friends’ blogs
  • Favorite teachers
  • Sexual preference
  • Religious views
  • Political views

The data is really limitless, but after all isn’t that what a nice web 2.0 application is supposed to provide? On the surface some of this data may seem silly for password resets but it is really not. This not so obvious information can be really helpful when when non-standard questions are used in the password reset process. This typically happens when people are left to their own devices when creating security questions. They typically create questions that are common and familiar to them. Stupid things like pet’s names, favorite teams, favorite TV shows, etc.

Just think for a moment about tagging. People may tag photos themselves with useful information. Also, friends may tag people in photos helping better define a person’s relationships with people and activities they are involved in. The URL of the social network may lead you to potential usernames / IM information such as www.myspace.com/(username). Maybe the data is completely visual like photo data. A lot of information can be obtained by looking at pictures. Favorite places, sports teams, cars, and countless other possibilities. You name it, people like pictures with their favorite things.

The actions people take on social networks helps better define relationships, networks, group affiliations, and activities. The person may place comments on other people’s photos, profiles, walls, blogs, etc. You may see comments like “That is why you are my BFF”. You may also see that someone is a member of a political party or religious group. People may discuss on boards or blogs about certain things happening in their life. Sharing is caring right?

So what you get in the end is a clear picture of who these people are. You get their likes, dislikes, friends, and affiliations are all in a nice clean package. You may have never even met this person but you have all of the information a traditional friend may have, possibly more.

Need a bit more?

If you almost have the nail in the coffin then you can turn to other sites to complete the task. You could look for name / username collisions on other sites to gain more data. You could take their high school and age information and find out who they went to school with. The possibilities are endless.

The User’s Choice

When people are given the option to choose their own security it has historically been bad. There is nothing that seems to suggest that allowing user’s to choose their security will get any better, so some of this may be wasted breath.

When looking at sites like Google, it seems they have slightly better security questions. Questions such as your library card number, frequent flyer number, etc. I think sites like these with better security questions probably have a high amount of people that end up just choosing their own questions when this option is available. People don’t seem to understand that this isn’t a function that you are going to use everyday. It is ok and preferable to use data that you may not be able to recall without looking up.

So What Can We Do?

The problem of personal data leakage isn’t going to stop until people realize the potential impacts of their data being strung out for the whole world to see. I personally don’t think this will change, in fact, I think with time it will get a lot worse. We live in this voyeuristic, virtual world where people create digital representations of how they see themselves. I think that has an appeal to many people, especially those who don’t particularly find their lives that exciting.

Don’t play by the rules when dealing with a sites password reset questions. Put blatantly wrong, hard to guess, or nonsensical information in to the answer blocks. This will make any information gathered on you useless when attempting to recover your password.

It seems that many sites want you to log in. You shouldn’t use the same password on every site. Use a trusted password safe such as KeePass to store your login credentials. KeePass is open source and multi-platform. Using a mechanism like this allows you to be in control of your password recovery along with allowing you to use different passwords for different sites. It would also be a good idea to back up the database of whatever password safe you choose to use as well. Just a thought ;)

The biggest mistake someone can make is thinking that there is nobody out there that gives enough of a crap about them to attack their accounts. People do weird things. Anybody is capable of just about anything. This isn’t being paranoid, it’s being safe. Think of it as locking the door on your house when you leave, only instead of your valuables you are protecting your data.

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