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O2 Privacy Flaw Sends Users' Mobile Numbers to Visited Websites

As noted by think broadband, a privacy flaw in the way UK carrier O2 handles web traffic on mobile devices has resulted in users' mobile numbers being sent to any website visited from the device as part of the headers in the HTTP requests. While O2 is apparently still investigating the situation, it appears to have the potential for significant privacy-related issues.
If you're reading this news article using your O2 mobile phone, you'll be pleased to know that O2 have already sent us your mobile phone number within the HTTP headers which normally contain information about how content can be displayed on your device. These headers are not normally seen by users, and usually not logged by most websites, but the flaw allows malicious sites to get more personal information about you than you may be willing to share.

For example, if you open an e-mail which includes references to external images, the mere action of opening the e-mail would divulge your phone number. This could be used by anyone undertaking a phishing attack or other scam to get more information from you. The opportunity to abuse this is potentially endless.
The issue was discovered by Twitter user @lewispeckover, who then set up a website to allow users to see what headers are being sent as part of their HTTP requests to websites.

He now notes that the headers coming from his device appear to have stopped showing his mobile phone number, although O2 has yet to issue an official statement on the matter. The company's Twitter account is continuing to blast out responses to concerned users, noting only that the company is looking into the situation and will issue an update when it knows more.

The issue is not exclusive to the iPhone and has the potential to affect all mobile data on the second-largest carrier in the UK, although some users have reported that they are not seeing their mobile numbers appearing in their HTTP request headers. The issue has the potential to for a significant impact on UK iPhone users, as O2 has proven to be a popular choice for iPhone users dating back to its status as the exclusive iPhone carrier in the UK when the device originally launched back in 2007.

Those familiar with the UK's privacy laws have indicated that mobile phone numbers are not considered protected information, but the disclosure of such numbers as part of standard HTTP requests does have the potential to carry implications for users.

Top Rated Comments

(View all)

38 months ago
I've really not been impressed by O2 in recent years. I first joined them in 2006, but ever since then, their network coverage in the 20 mile radius of here (near Bath) hasn't improved one bit. The 3G coverage is absolutely awful. If you aren't in a major town or a city, you have no chance of 3G with O2, only dial-up speed GPRS. Not even EDGE in most cases.

Everything Everywhere are very good, but Three (in the south of England at least) are best by far for 3G coverage.

Perhaps if O2 spent more money on, well, being a service provider and improving their network, rather than all that "priority moments" crap, they might increase their 3G coverage.
Rating: 6 Votes
38 months ago
The "O" is for "Oops!"
Rating: 4 Votes
38 months ago

Not so in my o2 account with an iPhone using iOS 5.0.1 via Safari.


It wasn't inserted into the user agent, it was a separate header: "x-up-calling-line-id".
Rating: 4 Votes
38 months ago
From TFA


Another annoying feature of O2 is that they interfere with the responses from servers too. They downgrade all images and insert a javascript link into the HTML of each page. I've talked to customer service about this lovely feature several times, but they never have a clue what I'm talking about, let alone any idea how to opt out/disable it.

I asked O2 about this a couple of years ago and asked to have a copy of their privacy policy. They didn't have one, and perhaps still do not.

Contract customers can switch it off by using different APN credentials. PAYG and giffgaff customers cannot turn it off.
Rating: 2 Votes
38 months ago
Makes me glad I'm with Orange UK. If this story is true, then O2 are really going to have egg on their face....

Anybody know what the salary/bonus is for the CEO of O2?
Rating: 2 Votes
38 months ago
This does appear to have been fixed in the last hour, but is typical for O2. I'm sure many of you remember when O2 sent the credit card numbers of iPhone users attempting to opt out of their ludicrous age verification system in plaintext, and then preceeded to lie about it ever happening and censor any posts about it on their own boards or blogs.

Phazer
Rating: 2 Votes
38 months ago

I am now intrigued though as to who the "trusted partners" are. O2 themselves and BT Openzone are the only ones I can think of.


One is Bango, the company that runs O2's adult verification software and thought sending credit card numbers in plaintext over http was a good idea.

O2 might "trust" them. I don't.

Phazer
Rating: 2 Votes
38 months ago
I'm appalled they let this in.

I'm thrilled they fixed it so quickly.

I'm going to treat o2 with a bit more suspicion from here on out.
Rating: 2 Votes
38 months ago
I'm perfectly happy with O2, I've found the coverage decent and I don't get loads of junk text messages from them like I did from Vodafone*. This latest gaffe is a bit annoying, but whatever, as a business owner my details are well and truly 'out there' for all the lowlife to exploit anyway. Bring it on scumbags.

*The junk texts don't stop when you leave Vodafone. The other day I received a text that said "Come back to Vodafone and we'll give you a free Windows 7 laptop". If there's one thing that would be guaranteed to STOP me going back to them, it's the threat of a crappy low end piece of junk with a crappy low end OS turning up at my house.
Rating: 2 Votes
38 months ago
O2 have just released a Q&A regarding this: link (http://blog.o2.co.uk/home/2012/01/o2-mobile-numbers-and-web-browsing.html)

O2 mobile numbers and web browsing

Security is of the utmost importance to us and we take the protection of our customers’ data extremely seriously.

We have seen the report published this morning suggesting the potential for disclosure of customers’ mobile phone numbers to website owners.

We investigated, identified and fixed it this afternoon. We would like to apologise for the concern we have caused.

Below is a set of Q&As, to answer questions we've been receiving. If you have further questions, do leave them in the blog comments and we will do our best to answer as many as possible.



Q: What's happened with O2 mobile numbers when I browse the internet on my mobile?

A: Every time you browse a website (via mobile or desktop), certain technical information about the machine you are using, is passed to website owners. This happens across the internet, and enables website owners to optimise the site you see. When you browse from an O2 mobile, we add the user's mobile number to this technical information, but only with certain trusted partners. This is standard industry practice. We share mobile numbers with selected trusted partners for 3 reasons: 1) to manage age verification, which manages access to adult content, 2) to enable third party content partners to bill for premium content such as downloads or ring tones that the customer has purchased 3) to identify customers using O2 services, such as My O2 and Priority Moments. This only happens over 3G and WAP data services, not WiFi.



Q: How long has this been happening?

A: In between the 10th of January and 1400 Wednesday 25th of January, in addition to the usual trusted partners, there has been the potential for disclosure of customers’ mobile phone numbers to further website owners.



Q: Has it been fixed?

A: Yes. It was fixed as of 1400 on Wednesday 25th January 2012.



Q: Which of my information can website owners access?

A: The only information websites had access to is your mobile number, which could not have been linked to any other identifying information we have about customers.



Q: Why did this happen?

A: Technical changes we implemented as part of routine maintenance had the unintended effect of making it possible in certain circumstances for website owners to see the mobile numbers of those browsing their site.



Q: Which customers were affected?

A: It affected customers accessing the internet via their mobile phone on 3G or WAP services, but not WIFI, between 10th of January and 1400 on Wednesday the 25th of January.



Q: Which websites do you normally share my mobile number with?

A: Only where absolutely required by trusted partners who work with us on age verification, premium content billing, such as for downloads, and O2's own services, have access to these mobile numbers.



Q: The Information Commissioner said he is investigating - what are you doing as part of this?

A: We are in contact with the Information Commissioner's office, and we will be co-operating fully. We have also contacted OFCOM.

Rating: 2 Votes

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