O2 UK accused of sharing phone numbers to websites, O2 Ireland unaffected

25 Jan 2012

O2 UK has been accused of accidentally sharing phone numbers to each site that users visit on their smartphones through its mobile data network. Meanwhile, O2 Ireland said its customers were unaffected by this issue.

Lewis Peckover developed a web page which shows the user’s header data. He claims that when an O2 UK user visits a website with a smartphone through a mobile data network, his or her phone number gets displayed in the “x-up-calling-line-id” field, suggesting this information gets sent to each website visited.

Peckover says it’s not being caused by the client and says O2 UK appears to be transparently proxying HTTP traffic and inserting this header.

The Verge confirmed this was happening on two phones on the O2 UK network, whereas Orange, Three UK and Vodafone UK numbers were unaffected.

However, an O2 Ireland spokesperson sold Siliconrepublic.com that its customers were unaffected by the issue and that it runs its services independently from its UK operations. We tested it out with a smartphone connected to the O2 Ireland network and found that the phone number did not appear in the header data on Peckover’s site.

O2 UK said it was investigating the issue and will update its users once they find out more.