Patch ASAP: Max-Critical Atlassian Bug Allows Unauthenticated RCE

A max-critical unauthenticated remote code execution (RCE) vulnerability is impacting Atlassian Confluence Data Center and Confluence Server, in all versions released before Dec. 5. Unpatched organizations should prepare to defend against everything from ransomware campaigns to cyber-espionage attempts.

The bug (CVE-2023-22527), which carries a 10 out of 10 vulnerability-severity rating on the CVSS v3 scale, is a template injection vulnerability that paves the way for unauthenticated attackers to achieve RCE on versions 8.0.x, 8.1.x, 8.2.x, 8.3.x, 8.4.x, and 8.5.0 through 8.5.3.

Bug Plagues Most Versions of Confluence

Any organization that has upgraded to Confluence versions released in the company's December update are in the clear, though the bug was disclosed just today, along with several less-severe vulnerabilities that are newly patched in a fresh security bulletin.

Atlassian noted that end-of-life instances (version 8.4.5 and before) are also affected and will not receive patches.

There are no mitigations or workarounds available, so admins should apply the latest versions from last month to be fully protected, even if their versions of Confluence aren't exposed to the Internet. Cloud instances are unaffected.

For those who can't immediately patch their Confluence Data Center and Server instances, Atlassian recommends they remove their systems from the Internet and back up their data outside of the Confluence environment.

Atlassian CVE-2023-22527 Attacks Could Be Wide-Ranging

The company also suggested monitoring for any potential malicious activity (naturally) but noted in its security advisory on CVE-2024-22527 that "the possibility of multiple entry points, along with chained attacks, makes it difficult to list all possible indicators of compromise."

Admins should take note: Atlassian Confluence bugs are generally popular on the cybercrime circuit, given that the platform reaches deep into network environments, used for cross-enterprise collaboration, workflow, and software development. Another 10-out-of-10 critical bug in November was swarmed with exploitation attempts within days of its disclosure, and it's likely the same will hold true for this one if past is prologue; with Atlassian, it usually is.