Original URL: http://www.theregister.co.uk/2013/06/06/linkedin_snarfing_contacts_from_exchange/

LinkedIn snarfing contacts from Exchange

Default server settings surrender data to social network

By Simon Sharwood

Posted in Security, 6th June 2013 05:26 GMT

Update LinkedIn offers lots of chances for its users to hand over credentials so the social business network can suggest new connections. But a new offer to do so for Microsoft Outlook means contacts can be sucked out of Microsoft Exchange and exposed to the world.

Australian sysadmin Adam Fowler noticed the feature and detailed its behaviour in a blog post that explains what happened when he create a test account on the Exchange server he administers:

“I tried this with a test account, entering the username and temporary password. It then asked for further information, which was the address for the Outlook webmail link and then connected and started showing contacts.

LinkedIn on this page says 'We'll import your address book to suggest connections and help you manage your contacts. And we won't store your password or email anyone without your permission'.”

Fowler's point is that users who innocently expose their contacts to LinkedIn are exposing Exchange Servers to a third party, which isn't a good idea. That LinkedIn can access the names and details of Contacts stored in a business' system – and perhaps gathered solely for business purposes – is also a worry as it enables a third party to understand links between two people that may not otherwise be made public.

And as Fowler points out, LinkedIn doesn't have the world's greatest security record.

Happily, Fowler has found that some tweaks to Exchange prevent LinkedIn from accessing contacts.

Here's his advice:

“There are a few settings to check. First, under the Set-OrganizationConfig area, you'll need to check that EwsApplicationAccessPolicy is set to 'EnforceBlockList'. If it's not, it's going to be 'EnforceAllowList' and you're probably OK, as it's using a whitelist for access to only what's listed rather than a blacklist, to only block what's listed. Next, you need to add LinkedIn into the BlockList. This is done with the command 'Set-OrganizationConfig -EwsBlockList LinkedInEWS'

The Reg has asked LinkedIn to comment on whether it is appropriate for its Outlook connection service to reach into Exchange servers and will update this story if a response is offered. ®

Update

LinkedIn has contacted us with the following statement:

"We take the privacy and security of our members’ data very seriously. Accordingly, the functionality of importing contacts from Outlook is an opt-in feature that allows members to add connections. We have also proactively provided instructions for Corporate IT managers to disable the ability for employees at companies to import contacts from their work email accounts and you can find more information here.”

We've also heard from Exchange Expert Paul Cunningham, who has detailed his own explorations of this "feature" and found LinkedIn doesn't just look at Contacts, but also reads Sent Mail messages and hoovers them up.