Smartphone monitoring firm Mobile Spy has fixed a security hole that exposed the data of all its users to public display.

The company makes software that records every call and SMS made from a mobile phone, but a flaw in the company's website meant that the demo page could be used to read all the data of customers who used the service.

Sean Sullivan, a senior researcher at F-Secure, demonstrated the flaw last week to vnunet.com, which then contacted the software's manufacturer asking for comment.

"The data leakage described is not possible with our servers," replied James Johns, chief executive of software creator Retina-X Studios, at 1.47am BST this morning.

"Anyone trying this method would receive a message denying access. Retina-X Studios takes customer privacy very seriously. We have tested all services to verify that this is not an issue."

After checking the website, Sullivan confirmed that the problem had just been fixed. He has detailed the issue and provided screenshots on an F-Secure blog.

"They have fixed the problem," he said. "It is the same response as we got from FlexiSPY when we alerted them to the same problem. They have pretty much corrected it the same way too."