Atlassian patches under-attack Confluence zero-day

Atlassian is warning that some instances of its Confluence data centre and server software may have been exploited and has moved to patch the products.

The company’s advisory said the critical-rated bug, CVE-2023-22515, may have been exploited in some customers, to “create unauthorised Confluence administrator accounts and access Confluence instances.”

The company said cloud instances accessed via an Atlassian domain are not affected.

The bug affects Confluence data centre and server versions between 8.0.0 and 8.5.1; versions prior to that are not affected.

The patch has been applied to version 8.3.3, 8.4.3, or 8.5.2 and later.

In a blog post, Cloudflare said it was alerted to the bug by Atlassian ahead of the advisory and had applied web application firewall rules to prevent exploitation for its customers.

Customers not yet able to patch can restrict network access to affected instances, Atlassian’s advisory stated.

They can also block access to the /setup/* endpoints on Confluence instances.

The company said indicators of compromise include the presence of unexpected, newly created user accounts; unexpected members of the admin group; log entries showing requests to /setup/*.action; or a log entry containing an exception message containing /setup/setupadministrator.action.