A critical zero-day vulnerability in Atlassian Confluence Data Center and Server is under active exploitation, the software maker has warned on Thursday.
There is currently no fix available – though they are expected to be released today – and users of the popular enterprise collaboration solution are advised to either temporarily restrict access to Confluence Server and Data Center instances from the internet, or to disable them completely.
Atlassian has declined to share specific details about the nature of CVE-2022-26134 until a fix is ready – we only known that the vulnerability can be exploited by unauthenticated attackers to achieve remote code execution, and that it affects all supported versions of Confluence Server and Data Center and likely all unsupported ones.
During an incident response investigation, they found two internet-facing web servers running Atlassian Confluence Server software compromised via a JSP variant of the China Chopper webshell.
As noted previously, Atlassian advises users to restrict internet access to Confluence Server and Data Center or to disable them completely.
Security teams should also check whether organizations’ Atlassian Confluence installations have been compromised, and to help with that Volexity released IOCs and hunting rules.