CVE-2021-32747

Icinga Web 2 is an open source monitoring web interface, framework, and
command-line interface. A vulnerability in which custom variables are exposed
to
unauthorized users exists between versions 2.0.0 and 2.8.2. Custom variables
are
user-defined keys and values on configuration objects in Icinga 2. These are
commonly used to reference secrets in other configurations such as check
commands to be able to authenticate with a service being checked. Icinga Web 2
displays these custom variables to logged in users with access to said hosts or
services. In order to protect the secrets from being visible to anyone, it's
possible to setup protection rules and blacklists in a user's role. Protection
rules result in `***` being shown instead of the original value, the key will
remain. Backlists will hide a custom variable entirely from the user. Besides
using the UI, custom variables can also be accessed differently by using an
undocumented URL parameter. By adding a parameter to the affected routes,
Icinga
Web 2 will show these columns additionally in the respective list. This
parameter is also respected when exporting to JSON or CSV. Protection rules and
blacklists however have no effect in this case. Custom variables are shown
as-is
in the result. The issue has been fixed in the 2.9.0, 2.8.3, and 2.7.5
releases.
As a workaround, one may set up a restriction to hide hosts and services with
the custom variable in question.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-32747
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-32747
https://github.com/Icinga/icingaweb2/releases/tag/v2.7.5
https://github.com/Icinga/icingaweb2/releases/tag/v2.8.3
https://github.com/Icinga/icingaweb2/security/advisories/GHSA-2xv9-886q-p7xx
https://github.com/Icinga/icingaweb2/releases/tag/v2.9.0