Facebook-for-bosses website LinkedIn has fixed a security vulnerability that potentially allowed anyone to swipe users’ OAuth login tokens.

The flaw came to light after British software developer Richard Mitchell discovered part of the LinkedIn’s customer help website handed out the private OAuth token of the logged-in user. These otherwise secret tokens can be used by anyone to masquerade as LinkedIn users linked to those tokens, and potentially access profile information using APIs.

Before handing over the sensitive data, JavaScript code on the help site merely checked that the previously visited page was served from LinkedIn.com – a trivial HTTP referrer check that can be easily circumvented. Thus, someone could log into LinkedIn and surf to a malicious web page with code embedded to poke the help site for the victim’s OAuth token.

SOURCE: theregister.co.uk