DIVD-2021-00011 - Kaseya VSA Disclosure

Summary

One of our researchers found multiple vulnerabilities in Kaseya VSA, which we were in the process of responsible disclosure (or Coordinated Vulnerability Disclosure) with Kaseya, before all these vulnerabilities could be patched a ransomware attack happened using Kaseya VSA.

Ever since we released the news that we indeed notified Kaseya of a vulnerability used in the ransomware attack, we have been getting requests to release details about these vulnerabilities and the disclosure timeline. In line with the guidelines for Coordinated Vulnerability Disclosure we have not disclosed any before 7 Juli 2021. And we have now released the full details of the vulnerabilities we discovered.

The vulnerabilities

We notified Kaseya of the following vulnerabilities:

• CVE-2021-30116 - A credentials leak and business logic flaw, to be included in 9.5.7
• CVE-2021-30117 - An SQL injection vulnerability, resolved in May 8th patch.
• CVE-2021-30118 - A Remote Code Execution vulnerability, resolved in April 10th patch. (v9.5.6)
• CVE-2021-30119 - A Cross Site Scripting vulnerability, to be included in 9.5.7
• CVE-2021-30120 - 2FA bypass, to be resolved in v9.5.7
• CVE-2021-30121 - A Local File Inclusion vulnerability, resolved in May 8th patch.
• CVE-2021-30201 - A XML External Entity vulnerability, resolved in May 8th patch.

What you can do

All on-premises VSA Servers should continue to remain offline until further instructions from Kaseya about when it is safe to restore operations. A patch will be required to be installed prior to restarting the VSA and a set of recommendations on how to increase your security posture.

Kaseya has released a Detection tool tool help determine if a system has been compromised.

Cado Security has made a github repository with Resources for DFIR Professionals Responding to the REvil Ransomware Kaseya Supply Chain Attack.

We recommend that any Kaseya server is carefully checked for signs of compromise before taking it back into service, including, but not limited to, the IoCs published by Kaseya.

What have done

The Dutch Institute for Vulnerability Disclosure (DIVD) performs a daily scan to detect vulnerable Kaseya VSA servers and notify the owners directly or via the known abuse channels, Gov-CERTs, and other trusted channels.

We have identified this server by downloading the paths ‘/’, ‘/api/v1.5/cw/environment’ and ‘/install/kaseyalatestversion.xml’ and matching patterns in these files.

In the past few days we have been working with Kaseya to make sure customers turn off their systems, by tipping them off about customers that still have systems online, and hope to be able to continue to work together to ensure that their patch is installed everywhere.

Timeline

More information

• official advisory from Kaseya
• DoublePulsar blog post
• Sophos blog post
• CISA-FBI Guidance for MSPs and their Customers Affected by the Kaseya VSA Supply-Chain Ransomware Attack
• Announcement of full disclosure