BT has squashed a mild website privacy bug reported by a Reg reader - but the telco has refused to address a related issue that allows anyone to add paid-for features to any BT landline.
The latter problem, described by the telco as a "customer convenience", can be exploited using just a property's postcode and phone number to cause mischief and inconvenience.
However, the other flaw, which revealed the full name of the landline account holder, has been fixed.
The Reg reader who raised the alarm, himself a BT customer, wanted to upgrade his landline account using the "Phone & Calling Plan" packages section of BT's website. After clicking on "start your order" the website allowed him to add paid-for options, such as unlimited calls, to his phone account with just the telephone number and postcode of his home.
At the end of the process the website shows a button for punters to press to create an account with bt.com to view online bills. Our man said: "When I clicked on that button it pre-filled the form with the full name of the primary account holder."
Neither of these processes disclosed payment information.
But our reader argued that the process has insufficient security, and that the account number should be requested when adding extra paid-for services to an account. He was even more concerned about the display of an account holder's name on the sign-up form for online bills, which he argued may be in breach of the UK's Data Protection Act.
"You should not be able to order additional paid-for services with publicly available information," said the customer, who wished to remain anonymous. "The phone number and postcode of a property are freely given out on letterheads, websites and all sorts.
"One could easily make a nuisance of oneself ordering extra services for someone and BT would be happy to comply with those requests, it seems. They should ask for the BT account number as well at the very least, since that is not something that people give out."
In response, BT conceded that displaying the name of the account holder was a mistake and agreed to change its process to not show it. However the telco giant argued that knowing the phone number and postcode of a property was enough security when it came to adding paid-for options to an account:
Different levels of security apply to different products. Where judged as appropriate, for the purpose of customer convenience we do allow a limited number of services to be ordered online using the phone number and postcode.
It should not have been possible to view the name of the account holder by entering just the phone number and postcode. Thank you very much for bringing this to our attention, we have taken the appropriate action to close this issue.