XSS in Checkmk

1) Cross-site scripting

EUVDB-ID: #VU65564

Risk: Medium

CVSSv3.1: 5.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-9781

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Exploit availability: No

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 - 1.4.0 p5

External links

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

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.