#VU65564 Cross-site scripting in Checkmk - CVE-2017-9781

Vulnerability identifier: #VU65564

Vulnerability risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Green]

CVE-ID: CVE-2017-9781

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Checkmk
Server applications / Other server solutions

Vendor: tribe29 GmbH

Description

The vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data passed via the "_username" parameter in webapi.py. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Checkmk: 1.4.0 p1 - 1.4.0

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External links
https://git.mathias-kettner.de/git/?p=check_mk.git;a=blob;f=.werks/4757;hb=c248f0b6ff7b15ced9f07a3df8a80fad656ea5b1
https://www.tenable.com/security/research/tra-2017-21

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.