Cross-site scripting in noVNC

1) Cross-site scripting

EUVDB-ID: #VU30739

Risk: Low

CVSSv4.0: 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:P/U:Clear]

CVE-ID: CVE-2017-18635

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

Exploit availability: Yes

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 when processing data passed via the messages propagated to the status field, such as the VNC server name. 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

Update to version 0.6.2.

Vulnerable software versions

noVNC: 0.6.0 - 0.6.1

CPE2.3

• cpe:2.3:a:kanaka:novnc:0.6.0:*:*:*:*:*:*:*
• cpe:2.3:a:kanaka:novnc:0.6.1:*:*:*:*:*:*:*

External links

https://access.redhat.com/errata/RHSA-2020:0754
https://bugs.launchpad.net/horizon/+bug/1656435
https://github.com/novnc/noVNC/commit/6048299a138e078aed210f163111698c8c526a13#diff-286f7dc7b881e942e97cd50c10898f03L534
https://github.com/novnc/noVNC/issues/748
https://github.com/novnc/noVNC/releases/tag/v0.6.2
https://github.com/ShielderSec/cve-2017-18635
https://lists.debian.org/debian-lts-announce/2019/10/msg00004.html
https://www.shielder.it/blog/exploiting-an-old-novnc-xss-cve-2017-18635-in-openstack/

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. However, proof of concept for this vulnerability is available.