A breach of customer data at URL shortening service Bit.ly was likely caused through unauthorized access of offsite backup data maintained by a third-party hosting provider, company officials say.
In a blog posted over the weekend, Bit.ly offered further explanation of its customer database breach, which was first reported on May 8. The compromise forced the company to invalidate all Twitter and Facebook credentials of its users and initiate a breach investigation.
The Bit.ly security team:
...observed that we had an unusually high amount of traffic originating from our offsite database backup storage that was not initiated by Bitly. At this point, it was clear that the best path forward was to assume the user database was compromised and immediately initiate our response plan, which included steps to protect our users’ connected Facebook and Twitter accounts.
We audited the security history for our hosted source code repository that contains the credentials for access to the offsite database backup storage and discovered an unauthorized access on an employee’s account. We immediately enabled two-factor authentication for all Bitly accounts on the source code repository and began the process of securing the system against any additional vulnerabilities.
Aside from invalidating users' Twitter and Facebook accounts to force password changes, the company has rotated all credentials for offsite storage systems and rotated all SSL certificates, the blog says. Bit.ly has reset credentials used for code deployment and added encryption of all sensitive credentials internally.
Bit.ly also is accelerating its program to offer two-factor authentication to its users, as well as a program that would give users email confirmation of password changes.
The company says that passwords in its user database may have been exposed, but that they were salted and hashed, which would make it difficult for attackers to use them.