Checkmk Cross-site Scripting

CheckMK Raw Edition software (versions 1.5.0 to 1.6.0) does not sanitise the input of a web service parameter that is in an unauthenticated zone. This Reflected XSS allows an attacker to open a backdoor on the device with HTML content and interpreted by the browser (such as JavaScript or other client-side scripts) or to steal the session cookies of a user who has previously authenticated via a man in the middle. Successful exploitation requires access to the web service resource without authentication. (2022-03-25, CVE-2021-40906)

Checkmk <=2.0.0p19 Fixed in 2.0.0p20 and Checkmk <=1.6.0p27 Fixed in 1.6.0p28 are affected by a Cross Site Scripting (XSS) vulnerability. The Alias of a site was not properly escaped when shown as condition for notifications. (2022-02-24, CVE-2022-24565)

In Checkmk <=2.0.0p19 fixed in 2.0.0p20 and Checkmk <=1.6.0p27 fixed in 1.6.0p28, the title of a Predefined condition is not properly escaped when shown as condition, which can result in Cross Site Scripting (XSS). (2022-02-24, CVE-2022-24566)

Checkmk <=2.0.0p19 contains a Cross Site Scripting (XSS) vulnerability. While creating or editing a user attribute, the Help Text is subject to HTML injection, which can be triggered for editing a user. (2022-02-21, CVE-2022-24564)

A stored cross site scripting (XSS) vulnerability in Checkmk 1.6.0x prior to 1.6.0p19 allows an authenticated remote attacker to inject arbitrary JavaScript via a javascript: URL in a view title. (2022-01-15, CVE-2020-28919)

The CheckMK management web console (versions 1.5.0 to 2.0.0) does not sanitise user input in various parameters of the WATO module. This allows an attacker to open a backdoor on the device with HTML content and interpreted by the browser (such as JavaScript or other client-side scripts), the XSS payload will be triggered when the user accesses some specific sections of the application. In the same sense a very dangerous potential way would be when an attacker who has the monitor role (not administrator) manages to get a stored XSS to steal the secretAutomation (for the use of the API in administrator mode) and thus be able to create another administrator user who has high privileges on the CheckMK monitoring web console. Another way is that persistent XSS allows an attacker to modify the displayed content or change the victim's information. Successful exploitation requires access to the web management interface, either with valid credentials or with a hijacked session. (2021-07-26, CVE-2021-36563)

Cross site scripting is an attack where a web page executes code that is injected by an adversary. It usually appears, when users input is presented. This attack can be used to impersonate a user, take over control of the session, or even steal API keys.

The attack can be executed e.g. when you application injects the request parameter directly into the HTML code of the page returned to the user:

https://server.com/confirmation?message=Transaction+Complete

what results in:

<span>Confirmation: Transaction Complete</span>

In that case the message can be modified to become a valid Javascript code, e.g.:

https://server.com/confirmation?message=<script>dangerous javascript code here</script>

and it will be executed locally by the user's browser with full access to the user's personal application/browser data:

<span>Confirmation: <script>dangerous javascript code here</script></span>