Security Notification and Linode Manager Password Reset
I'm glad to see that this information has now been publicly disclosed. In July 2015, we suffered a compromise at PagerDuty via the Linode Manager. I hope that we can provide a bit more of an official in-depth post-mortem of our compromise, but I'd be happy to disclose some of the details here.Using the access gained within the Linode Manager, the attacker reset the root password on a few systems, and used Lish to gain root access. We were alerted to this activity and fully revoked the attacker's access within 60 minutes of the first node being compromised. Working with Linode support, we discovered which user account was being used and completely deactivated the user. We also isolated the VMs, and performed forensics on read-only copies of their disk images.In our situation the attacker knew one of our user's passwords and MFA secret. This allowed them to provide valid authentication credentials for an account in the Linode Manager. It's worth noting that all of our active user accounts had two-factor authentication enabled. An interesting data point was that the user who had their account compromised was no longer in possession of the MFA secret themselves. Their cell phone had been reset (thus deleting all data) 8 months prior. The user could not log in to the Linode Manager if they wanted, so it was our determination that the key could not have been obtained from the user and was more likely on Linode's side.We also have evidence from access logs provided by Linode that the attackers tried to authenticate as an ex-employee, whose username ONLY existed in the Linode database. It was absolutely unique and was not used elsewhere by the employee making the username an accidental honeypot. This was another piece of data supporting that Linode was the source of our compromise.We immediately reached out to them not only to inform them of their compromise, but to assist them in investigating it. We were confident that the Linode database had been breached, and that the secret key used to encrypt information in the database had been compromised as well.In addition to reaching out to Linode, we also worked with a third-party security firm to audit our work done during the incident. Likewise, around the same time we reached out to law enforcement to assist in investigating the attack. I believe our public disclosure includes this information[1]. This was in the middle of July 2015.We did not get confirmation in July that there was a breach of the Linode Manager or any associated credentials.In the end, we migrated away from Linode because of this breach (even before it was publicly disclosed) in Aug 2015. We also never were able to confidently disclose that Linode was the vector due to lack of confirmation from their end. While all of us who responded to the incident were confident they were the source, we now thankfully have the data to confirm it.[1] https://www.pagerduty.com/blog/july-2015-security-announceme...