Basic design flaws on a Labour party members forum exposed the email addresses of users to harvesting.
Surfers who register through the site http://members.labour.org.uk were invited to confirm their membership, and activate their account, by clicking on the link in an email sent to a specified account.
The email follows the form http://members.labour.org.uk/man-auth/ActivationSent/10000XXXXX
A Reg reader who registered through the site realised that the number at the end of this URL is probably sequential, a unique id which refers to the account just registered. Sure enough, just changing the ID in the URL to a lower number led to the presentation of an email address of another registrant ...
Rik Ferguson, a security consultant at Trend Micro, helped El Reg confirm the flaw, which he explained had resulted from a failure to follow established best practice in website design.
"By simply stepping backwards through the number sequence it is possible to harvest the email addresses of all the people who have registered before you," Ferguson explained. "Of course this could easily be automated and the full list could be harvested in a few seconds."
"The problem is that whoever is responsible for the website design uses a direct object reference in the URL (ie: the sequential number). Not only is the reference direct, it is also sequential, making it simple to guess. Best practice is to avoid any kind of direct object reference, instead using the URL to point to an internal index or other indirect reference map. If the URL must contain a direct reference then access to it should be secured by authentication," he added.
We notified Labour's website of the flaw late last week. By Tuesday evening Labour digital staffers were well on top of the problem.
"The Labour Party is always looking for ways to improve our digital presence," a New Labour spokesman told El Reg. "We were already in the process of updating our website's sign-in security and as part of this, the issue in question has been resolved."
It's worth emphasising that the breach was restricted to email addresses and that no other information, much less payment information, was disclosed. Nonetheless the general public are entitled to hold Labour to a higher standard than a Mom and Pop shop, especially given the party's advocacy of putting such a large amount of citizens' personal information on databases while it was in power. Against this the potential rewards from a targeted phishing attack based on the easily obtained email list would have been considerable. ®