Skip to main content

Mobile subscriber leakage in HTTP headers in the wild

At the end of January mobile phone company O2 admitted that because of a technical failure it had been leaking the mobile phone numbers of people who browsed using their phones on the O2 network. The phone numbers were being leaked to the web sites people visited.

On that day I set up logging on jgc.org to see if the same thing happened again, and to gather information on in the wild leakage of phone numbers in HTTP headers. The bottom line is that in a month of gathering data I've seen phone numbers sent to my server likely without the person browsing knowing.

The most common headers I've seen are MSISDN and X-MSISDN. Both seem to contain the phone's MSISDN (i.e number). About 1 in every 22,000 visits to the site had the MSISDN header in it with something that looked like a valid phone number.

Another common header was X-UP-SUBNO which AT&T apparently adds. This contains a unique identifier for the subscriber. A typical X-UP-SUBNO in my log files looks like: T_ILL_CHI_1311xxxxxx00010xxxxxxx or T_DLS_DFW_1283xxxxxx00010xxxxxxx (I have replaced some numbers with x to preserve the visitor's privacy). About 1 in every 3,000 visits to jgc.org had a unique AT&T identifier in it. This doesn't appear to be the phone number.

One mobile visitor in the last month had headers called X-UP-SUBSCRIBER-COS, X-OPWV-DDM-HTTPMISCDD, X-OPWV-DDM-IDENTITY, X-OPWV-DDM-SUBSCRIBER. Between them they were full of base 64 encoded data containing details of what appeared to be the plans the subscriber was on (mobileGenericPlan, Vodacom, mobilePushEnabledPlan). And there were a variety of identifiers for the subscriber, device and 'station id'.

Then there were a bunch of headers apparently added by Sprint PCS containing a CLIENTID encoded with base 64. And Vodafone seemed to be injecting big chunks of base64 in an X-VF-ACR header.

It's hard to see why these headers should be sent all the way to the origin web server.

PS While looking at the headers the most WTF I came across were the headers X_MTI_USERNAME, X_MTI_EMAIL and X_MTI_EMPID which appeared to be giving the username, email address and employee ID(?) of someone at a company called Meyer Tool.

Comments

Popular posts from this blog

Your last name contains invalid characters

My last name is "Graham-Cumming". But here's a typical form response when I enter it:


Does the web site have any idea how rude it is to claim that my last name contains invalid characters? Clearly not. What they actually meant is: our web site will not accept that hyphen in your last name. But do they say that? No, of course not. They decide to shove in my face the claim that there's something wrong with my name.

There's nothing wrong with my name, just as there's nothing wrong with someone whose first name is Jean-Marie, or someone whose last name is O'Reilly.

What is wrong is that way this is being handled. If the system can't cope with non-letters and spaces it needs to say that. How about the following error message:

Our system is unable to process last names that contain non-letters, please replace them with spaces.

Don't blame me for having a last name that your system doesn't like, whose fault is that? Saying "Your last name …

All the symmetrical watch faces (and code to generate them)

If you ever look at pictures of clocks and watches in advertising they are set to roughly 10:10 which is meant to be the most attractive (smiling!) position for the hands. They are actually set to 10:09.14 if the hands are truly symmetrical. CC BY 2.0image by Shinji
I wanted to know what all the possible symmetrical watch faces are and so I wrote some code using Processing. Here's the output (there's one watch face missing, 00:00 or 12:00, because it's very boring):



The key to writing this is to figure out the relationship between the hour and minute hands when the watch face is symmetrical. In an hour the minute hand moves through 360° and the hour hand moves through 30° (12 hours are shown on the watch face and 360/12 = 30).
The core loop inside the program is this:   for (int h = 0; h <= 12; h++) {
    float m = (360-30*float(h))*2/13;
    int s = round(60*(m-floor(m)));
    int col = h%6;
    int row = floor(h/6);
    draw_clock((r+f)*(2*col+1), (r+f)*(row*2+1), r, h, floor(m…

The Elevator Button Problem

User interface design is hard. It's hard because people perceive apparently simple things very differently. For example, take a look at this interface to an elevator:


From flickr

Now imagine the following situation. You are on the third floor of this building and you wish to go to the tenth. The elevator is on the fifth floor and there's an indicator that tells you where it is. Which button do you press?

Most people probably say: "press up" since they want to go up. Not long ago I watched someone do the opposite and questioned them about their behavior. They said: "well the elevator is on the fifth floor and I am on the third, so I want it to come down to me".

Much can be learnt about the design of user interfaces by considering this, apparently, simple interface. If you think about the elevator button problem you'll find that something so simple has hidden depths. How do people learn about elevator calling? What's the right amount of informati…