Customer service software provider Zendesk announced a security breach that allowed attackers into its system, where they could access data from three customers this week. Wired learned those three clients were Twitter, Pinterest and Tumblr.
The San Francisco-based company announced the breach in a blog post published early Thursday night. Tumblr notified affected users in an email at approximately 6:35 p.m. PST; Twitter and Pinterest are expected to do so shortly. Zendesk declined to comment beyond its blog post, titled, appropriately, "We've been hacked." The post reads in part:
We’ve become aware that a hacker accessed our system this week. As soon as we learned of the attack, we patched the vulnerability and closed the access that the hacker had. Our ongoing investigation indicates that the hacker had access to the support information that three of our customers store on our system. We believe that the hacker downloaded email addresses of users who contacted those three customers for support, as well as support email subject lines. We notified our affected customers immediately and are working with them to assist in their response.
Zendesk allows companies to outsource many of their customer service functions to it via software tools. It has more than 25,000 clients, according to its website.
Zendesk noted that a hacker downloaded e-mail addresses of users who contacted those three customers for support, along with the e-mail subject lines. Wired's source claims some customers also may have had their phone numbers revealed, but no passwords, password hashes, or even encrypted passwords were revealed. Neither Twitter, Pinterest nor Tumblr are aware of any user accounts that were compromised by the attack.
The e-mail sent by Tumblr states:
Important information regarding your security and privacy
For the last 2.5 years, we've used a popular service called Zendesk to store, organize, and answer emails to Tumblr Support. We've learned that a security breach at Zendesk has affected Tumblr and two other companies. We are sending this notification to all email addresses that we believe may have been affected by this breach.
This has potentially exposed records of subject lines and, in some cases, email addresses of messages sent to Tumblr Support. While much of this information is innocuous, please take some time today to consider the following:
The subject lines of your emails to Tumblr Support may have included the address of your blog which could potentially allow your blog to be unwillingly associated with your email address.
Any other information included in the subject lines of emails you’ve sent to Tumblr Support may be exposed. We recommend you review any correspondence you've addressed to support@tumblr.com, abuse@tumblr.com, dmca@tumblr.com,legal@tumblr.com, enquiries@tumblr.com, or lawenforcement@tumblr.com.
Tumblr will never ask you for your password by email. Emails are easy to fake, and you should be suspicious of unexpected emails you receive.
Your safety is our highest priority. We're working with law enforcement and Zendesk to better understand this attack. Please monitor your email and Tumblr accounts for suspicious behavior, and notify us immediately if you have any concerns.