A British Gas website that allows homeowners to pay bills leaves consumers exposed by inviting them to submit credit card information across an unencrypted link.

Consumers logging on to pay their bills through house.co.uk initially go through a secure server. But once they create an account and login they may be transferred to a payment server that fails to use a HTTPS connection. The problem is down to coding errors, according to a leading UK security consultancy.

"I went to pay my gas bill on-line on their website (www.house.co.uk). After creating an account and logging in (it was a secure URL for the login) I selected the 'pay bill' link," he writes. "I found that when I went to pay they asked me for my card information. I duly typed in my details and submitted payment. However, to my horror, straight after clicking 'pay' I noticed that all of this was on an unsecured connection (no https:// in the URL). So, my details could have easily been intercepted on the net."

Sometimes the use of frames on a site mean that users cannot see that they are using a HTTPS link and padlock are not display even though information is transferred over a secure link. However the problems with the house.co.uk site go deeper than this.

A security consultant at UK penetration testing firm SecureTest, and British Gas customer, was able to confirm the problem on his own account. It blames a pair of coding mistakes for the vulnerability, which only happens when users follow a particular path through the site.

"Once one logs in to the online application, if one clicks on the 'your accounts' link, the transaction correctly remains in HTTPS. However, if one clicks 'manage your bills' first after logging in, then clicks 'your accounts', the transaction flips to HTTP," explained SecureTest managing director Ken Munro.

Munro said that the problem arises because site coders have "clearly forgotten" to enforce HTTPS in a couple of the links on the site.

"The payments page is also available over HTTP, and it shouldn't be," he said, adding that British Gas had fallen foul of a type of unencryption problem that SecureTest witnesses all too frequently in its work.

We reported the apparent problems with the house.co.uk site to a representative of Centrica, which owns British Gas, earlier this week. The firm is yet to respond to our requests for comment. ®

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