O2 has plugged a security hole that allowed customers to view text messages sent by other UK subscribers online.
The issue involves O2's Bluebook application, which allows subscribers to save any text messages they send or receive for viewing online. Coding errors in Bluebook created a means for registered users to view other user's messages (and phone numbers) simply by changing the message ID number in URLs used to access messages on the site. In a statement, the mobile phone giant said that it has fixed the problem.
"We have identified and closed a loophole in Bluebook which allowed O2 Bluebook customers logged into their own account to view the message of another Bluebook customer by changing the URL in the browser window. This allowed them – in one particular window only - to view a random text message of another Bluebook user and in some cases the phone number of the sender," an O2 spokeswoman explained.
O2 said the security slip-up emerged as the "result of an internal review" on Friday 8 February. It said the loophole was closed on Monday 11 February. The issue was reported to us by Reg reader Tom, who claimed that the issue was actually reported to O2 on 4 February.
The mobile phone operator apologised for the slip-up, adding that it had implemented unspecified security measures to guard against similar coding problems in future.
"We apologise to our Bluebook customers for this lapse. We have conducted a thorough review to make sure it cannot happen again and that their details are secure," the spokewoman added.
Flaws that leave customer data viewable by simple URL manipulation are a common coding mistake, and one that 02 itself has fallen victim to in the past. The mobile phone giant was obliged to disable logins to its Bill Manager website in August 2006 when it emerged that registered users could see other customers' call records. The service, which allows small businesses to manage their spending on mobile calls, was subject to much the same URL manipulation coding snafu as the Bluebook site. The slip-up exposed sensitive call records, though more sensitive billing records were not accessible through the application and therefore not exposed.
URL manipulation also opened the way for the curious to view the details of applicants applying for jobs at oil giant Shell in Jan 2003. More seriously, the same class of vulnerability exposed credit card details of customers of utility Powergen back in July 2000. ®