Slack, the chatting app for co-workers that's worth more than $1 billion, has been hacked

Slack, the business communication app that is now reported to be worth over $2 billion, has experienced hacker attacks on its central user database, resulting in a possible breach of user data, Slack wrote in a blog post Friday.

"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," it said.

Although Slack said there was no indication of hackers decrypting passwords or financial payment information, it did note hackers had access to the information contained in its user database, which stores user names, email addresses, and encrypted passwords.

The attacks occurred for about four days in February, the company's blog post said. Slack also said there has been suspicious activity in a "very small number of accounts," and those account owners have been notified individually.

As part of its effort to beef up security, Slack has released two new features Friday, including two-factor authentication and a new team-wide "password kill switch" that can instantly reset passwords of all team members. You can learn more about it at Slack's homepage here.