A Vulnerability in Confluence Server and Data Center Could Allow for Arbitrary Code Execution

by CIRT Team

13 Sep 2021

in Security Advisories & Alerts

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DESCRIPTION:
A vulnerability has been discovered in Confluence Server and Data
Center, which could allow for arbitrary code execution. Confluence is a
wiki tool used to help teams collaborate and share knowledge
efficiently. Successful exploitation of this vulnerability could allow
an unauthenticated user to execute arbitrary code on a Confluence Server
or Data Center instance. Depending on the privileges associated with the
instance, an attacker could view, change, or delete data.

IMPACT:
A vulnerability has been discovered in Confluence Server and Data Center
Could Allow for Arbitrary Code Execution. An OGNL injection could allow
an authenticated user, and in some instances an unauthenticated user, to
execute arbitrary code on a Confluence Server or Data Center instance.
The vulnerable endpoints can only be accessed if ‘Allow people to sign
up to create there account’ is enabled. Successful exploitation of this
vulnerability could allow an unauthenticated user to execute arbitrary
code on a Confluence Server or Data Center instance. Depending on the
privileges associated with the instance, an attacker could view, change,
or delete data.

SYSTEM AFFECTED:
* Confluence Server and Data Center all versions prior to 6.13.23
* Confluence Server and Data Center versions from 6.14.0 prior to 7.4.11
* Confluence Server and Data Center versions from 7.5.0 prior to 7.11.6
* Confluence Server and Data Center versions 7.12.x prior to 7.12.5

RECOMMENDATIONS:
We recommend the following actions be taken:

* Apply appropriate patches provided by Atlassian to vulnerable systems
immediately after appropriate testing.
* Run all software as a nonprivileged user (one without administrative
privileges) to diminish the effects of a successful attack.
* Evaluate read, write, and execute permissions on all newly installed
software.
* Apply the Principle of Least Privilege to all systems and services.

REFERENCES:
https://confluence.atlassian.com/doc/confluence-security-advisory-2021-08-25-1077906215.html
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-26084