Updated June 5 - Atlassian issued a fix for CVE-2022-30190 for versions 7.4.17, 7.13.7, 7.14.3, 7.15.2, 7.16.4, 7.17.4 and 7.18.1. The updated versions are available here.
Trustwave SpiderLabs is tracking the critical-rated zero-day vulnerability CVE-2022-26134. Threat actors are reported to be actively exploiting this vulnerability in the wild. Atlassian disclosed and issued guidance for CVE-2022-26134 on June 2.
Trustwave is diligently watching over our clients for exposure and associated attacks and working closely with our clients to ensure that mitigations are in place. Trustwave SpiderLabs is continuing to monitor this developing threat and we will update this blog as necessary.
Overview
On June 2, Atlassian released a security advisory outlining an active zero-day campaign targeting a critical flaw that is being tracked as CVE-2022-26134. The vulnerability currently affects all supported versions of Confluence Server and Confluence Data Center. Exploitation results in unauthenticated remote code execution. There is no patch available.
Details of the specific attack vector have not been released, but since one of the remediation options is to block or log URLs that contain the simple string "${", exploitation is likely trivial. No PoCs are currently available. Although one github account is trying to trick people into paying for an exploit, so be careful with any research you may perform.
Remediation
There are currently no fixed versions of Confluence Server and Data Center available, but Atlassian announced it will release patches by the end of the day June 3 PDT. In the meantime, Atlassian has released several temporary workarounds that you may want to implement.
Access or Availability Controls
Restrict access to Confluence Server and Data Center instances from the Internet or disable those instances entirely until a full fix is released.
Temporary File Fixes
Optionally, Atlassian has released some temporary fixed files that will remediate this issue until a complete fix is released. These fixes are version dependent.
For Confluence 7.15.0 - 7.18.0
You will need to download a new version of xwork-1.0.3-atlassian-10.jar and replace the one in the "<confluence-install>/confluence/WEB-INF/lib/" directory.
For Confluence 7.0.0 - Confluence 7.14.2
You will need to download new versions of:
- xwork-1.0.3-atlassian-10.jar
- webwork-2.1.5-atlassian-4.jar
and replace the files in the "<confluence-install>/confluence/WEB-INF/lib/" directory. You will also need to create a directory named:
<confluence-install>/confluence/WEB-INF/classes/com/atlassian/confluence/setup/webwork
and place there a downloaded copy of:
CachedConfigurationProvider.class
All new files and full instructions are on the Atlassian Security Advisory. Make sure you back up any original files and verify permissions to match the original settings. Also, if you run Confluence in a cluster, be certain to apply the update on all nodes.
WAF Filtering
If you are unable to take any of the above actions, you might consider implementing a WAF (Web Application Firewall) rule which blocks URLs containing "${" which may reduce your risk.
Reference
Atlassian Security Advisory: https://confluence.atlassian.com/doc/confluence-security-advisory-2022-06-02-1130377146.html
Initial write up including links to IP address IoCs and Yara rule: https://www.volexity.com/blog/2022/06/02/zero-day-exploitation-of-atlassian-confluence/
