We were recently able to confirm that there was unauthorized access to a Slack database storing user profile information. We have since blocked this unauthorized access and made additional changes to our technical infrastructure to prevent future incidents. We have also released two factor authentication and we strongly encourage all users to enable this security feature.
more here......http://slackhq.com/post/114696167740/march-2015-security-incident-and-launch-of-2fa
and an additional article titled "Slack Hack and Broken Model of Centralized Data
The recent Slack hack is another example of a fundamentally flawed model where a centralized company holds user data and provides access control." here......https://medium.com/@muneeb/slack-hack-and-centralized-data-b71bbe1b9377
more here......http://slackhq.com/post/114696167740/march-2015-security-incident-and-launch-of-2fa
and an additional article titled "Slack Hack and Broken Model of Centralized Data
The recent Slack hack is another example of a fundamentally flawed model where a centralized company holds user data and provides access control." here......https://medium.com/@muneeb/slack-hack-and-centralized-data-b71bbe1b9377