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O2 leaks 3G users' mobile numbers to every website visited

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Updated O2 UK is dishing out its customers' mobile numbers like free sweeties to every website they visit over a 3G connection.

The info leak was highlighted yesterday by O2 customer Lewis Peckover, who set up a little web tool that displays all the HTTP header information sent to sites by connecting web browsers. These strings of data include details such as the URL of the page requested, and the web browser and operating system versions used by the person visiting the site.

For customers browsing on an O2 3G connection, these headers also include their telephone number in an x-up-calling-line-id line - added in by proxy server software most likely running on the telco's network, rather than disclosed by a gadget's browser or software. Enterprising website owners can try to keep a copy of the HTTP header information sent over by visiting browsers and tie it to IP addresses and logins, if applicable.

Rival 3G networks are not appending visitors' phone numbers to the HTTP headers. O2 phones using Wi-Fi won't have the issue, nor will O2 users using web browsers such as Opera, which have their own proxy servers.

From reports on Twitter, BlackBerrys on O2 don't experience the problem because RIM runs its own proxy servers, and neither do O2 customers in Germany and other countries because the telco operates separate proxy servers in each nation.

The mobile number leak also affects GiffGaff and Tesco Mobile customers, whose networks piggyback O2's infrastructure. ®

Updated to add

While O2 says it is still investigating the matter, the number-leaking HTTP header has disappeared from the telco's 3G proxy system. ®

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Anonymous Coward

Oh SH*T!!!.

This means El Reg, the BBC, Wikipedia, Chix with Dix and Yahoo Search have my number. It's a perfect cluster f*ck of embarassment... I mean, come on, who would own up to using Yahoo search these days??

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Workaround

Users can work around this by using the username "bypass" in their APN settings rather than "o2web" or similar, this bypasses o2's proxy and prevents the number leak (as well as stopping the javascript link insertion and image compression o2's proxies also carry out).

This works for standard contracts, I have no idea whether PAYG or iPhone users can use the bypass username and still get a data connection.

6
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looks like the crooks spotted this last year

That would explain the bunch of text spam that started over xmas, the 1st time I used 3G data for quite some time and the crap started a few days in. Really must visit less dodgy sites I suppose ;)

There were a lot of premium text spam scams being reported on giffgaff late last year. I'm ready to believe this is actively being used by sms spammers.

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