A recently disclosed vulnerability in Atlassian Corp.’s Confluence Data Center and Server is being actively targeted in the wild and has been upgraded to a 10 on the Common Vulnerability Scoring System, the most severe rating possible.

The vulnerability, tracked as CVE-2023-22518, is an improper authorization vulnerability that allows an unauthenticated attacker to reset Confluence and create a Confluence instance administrator account. Using a compromised account, an attacker can perform all administrative actions available to a Confluence instance administration, including total loss of confidentiality, integrity and availability.

Notably, the vulnerability is not the same one as was disclosed in October, which resulted in the U.S. Cybersecurity and Infrastructure Agency, the Federal Bureau of Investigation and the Multi-State Information Sharing and Analysis Center releasing a Cybersecurity Advisory. That vulnerability, designated CVE-2023-22515, also had a CVE score of 10 but was a critical Broken Access Control vulnerability affecting versions of Atlassian Confluence Data Center and Server ranging from 8.0.0 through to 8.5.1.

The new vulnerability was first reported by Rapid7 Inc. on Nov. 6 to be being actively exploited. The vulnerability was observed being used to control Confluence in multiple customer environments, including for ransomware deployment.

Rapid7 first began responding to exploits using the vulnerability on Nov. 5. The process execution chain was reported to be primarily consistent across multiple environments, suggesting mass exploitation of vulnerability internet-facing Confluence services.

According to a security advisory from Atlassian, all versions of Confluence Data Center and Server are affected by this vulnerability. Notably, Atlassian released a patch for the vulnerability on Oct. 30, but as is typical in these situations, companies don’t patch as they are often unaware of the need to do so or may have limitations on being able to do so in a prompt fashion, leaving the door open to attackers.

Confluence users are being urged to patch each of their affected installations, but if they are unable to do so, there are temporary mitigations available. Users can remove their instance from the internet until they can patch it, or there are ways of blocking access to endpoints on Confluence instances.

Photo: Atlassian