O2 Privacy Flaw Sends Users' Mobile Numbers to Visited Websites

o2 logoAs 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

Elijahg Avatar
159 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.
Score: 6 Votes (Like | Disagree)
Elijahg Avatar
159 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".
Score: 4 Votes (Like | Disagree)
japanime Avatar
159 months ago
The "O" is for "Oops!"
Score: 4 Votes (Like | Disagree)
0098386 Avatar
159 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.
Score: 2 Votes (Like | Disagree)
The Phazer Avatar
159 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
Score: 2 Votes (Like | Disagree)
4D4M Avatar
159 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.
Score: 2 Votes (Like | Disagree)

Popular Stories

iPhone 16 Camera Lozenge 2 Colors

iPhone 16 Plus Rumored to Come in These 7 Colors

Wednesday April 10, 2024 3:52 am PDT by
Apple's iPhone 16 Plus may come in seven colors that either build upon the existing five colors in the standard iPhone 15 lineup or recast them in a new finish, based on a new rumor out of China. According to the Weibo-based leaker Fixed focus digital, Apple's upcoming larger 6.7-inch iPhone 16 Plus model will come in the following colors, compared to the colors currently available for the...
apple tv 4k yellow bg feature

When to Expect a New Apple TV to Launch

Tuesday April 9, 2024 8:30 am PDT by
It has been nearly a year and a half since the current Apple TV was released, so the device is becoming due for a hardware upgrade. Below, we recap rumors about the next Apple TV, including potential features and launch timing. The current model is the third-generation Apple TV 4K, announced in October 2022. Key new features compared to the previous model from 2021 include a faster A15...
apple silicon feature joeblue

Macs to Get AI-Focused M4 Chips Starting in Late 2024

Thursday April 11, 2024 10:10 am PDT by
Apple will begin updating its Mac lineup with M4 chips in late 2024, according to Bloomberg's Mark Gurman. The M4 chip will be focused on improving performance for artificial intelligence capabilities. Last year, Apple introduced the M3, M3 Pro, and M3 Max chips all at once in October, so it's possible we could see the M4 lineup come during the same time frame. Gurman says that the entire...
iOS 18 WWDC 24 Feature 2

iOS 18 May Feature All-New 'Safari Browsing Assistant'

Wednesday April 10, 2024 6:11 am PDT by
iOS 18 will apparently feature a new Safari browsing assistant, according to backend code on Apple's servers discovered by Nicolás Álvarez. MacRumors contributor Aaron Perris confirmed that the code exists, but not many details are known at this time. Álvarez said it seems like the browsing assistant will use iCloud Private Relay's infrastructure to send relevant data to Apple in a...
maxresdefault

Review: Six Months With the iPhone 15 Pro

Wednesday April 10, 2024 10:53 am PDT by
It's been a bit over six months since the iPhone 15 lineup came out in September, and MacRumors videographer Dan Barbera has been using an iPhone 15 Pro Max sans case since launch. Over on our YouTube channel, Dan did a long term review to demo how his phone has held up and his thoughts on the Action button, battery life, and camera features. Subscribe to the MacRumors YouTube channel for more ...
iPhone 16 Pro Sizes Feature

Alleged iPhone 16 Battery Details Show Smaller Capacity for One Model

Tuesday April 9, 2024 3:46 am PDT by
Apple's upcoming iPhone 16 lineup will feature bigger battery capacities compared to previous-generation models with the exception of the iPhone 16 Plus, which will have a smaller battery than its predecessor. That's according to the Chinese Weibo-based leaker OvO Baby Sauce OvO, a relatively new source of supply chain leaks with an as-yet unproven track record for accuracy. The iPhone 16 ...