Check_MK up to 1.4.0p5 webapi.py Username cross site scripting

Summaryinfo

A vulnerability was found in Check_MK up to 1.4.0p5. It has been rated as problematic. Affected is an unknown function of the file webapi.py. This manipulation of the argument Username as part of Parameter causes cross site scripting. The identification of this vulnerability is CVE-2017-9781. It is possible to initiate the attack remotely. There is no exploit available. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability has been found in Check_MK up to 1.4.0p5 and classified as problematic. Affected by this vulnerability is an unknown function of the file webapi.py. The manipulation of the argument username as part of a Parameter leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity. The summary by CVE is:

A cross site scripting (XSS) vulnerability exists in Check_MK versions 1.4.0x prior to 1.4.0p6, allowing an unauthenticated remote attacker to inject arbitrary HTML or JavaScript via the _username parameter when attempting authentication to webapi.py, which is returned unencoded with content type text/html.

The bug was discovered 06/21/2017. The weakness was shared 06/21/2017 as confirmed git commit (GIT Repository). It is possible to read the advisory at git.mathias-kettner.de. This vulnerability is known as CVE-2017-9781 since 06/21/2017. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 101089 (Check_MK < 1.4.0p6 webapi.py XSS), which helps to determine the existence of the flaw in a target environment. It is assigned to the family CGI abuses : XSS and running in the context r.

Upgrading to version 1.4.0p6 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at git.mathias-kettner.de. The best possible mitigation is suggested to be patching the affected component. A possible mitigation has been published even before and not after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (101089). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

• Check_MK

Version

• 1.4.0p5

CPE 2.3info

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CPE 2.2info

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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