Zendesk

The recent Zendesk hack that compromised user data from Twitter, Tumblr and Pinterest reflects the risks in using third-party service providers.

Zendesk sells cloud-based customer service software for storing, organizing and answering email sent to clients’ support staff. On Thursday, the company reported that a hacker had breached its systems this week and siphoned the email addresses and subject lines of three customers, which were identified by Wired as Tumblr, Pinterest and Twitter. The tech site also reported that some phone numbers were stolen.

Zendesk said Thursday a hacker gained access to support information for some customers of its online help desk software.

"We've become aware that a hacker accessed our system this week," wrote Mikkel Svane, Zendesk's CEO. "As soon as we learned of the attack, we patched the vulnerability and closed the access that the hacker had."