Vulnerability identifier: #VU26657

Vulnerability risk: Medium

CVSSv3.1: 5.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:P/RL:O/RC:C]

CVE-ID: CVE-2020-11457

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
pfsense
Server applications / IDS/IPS systems, Firewalls and proxy servers

Vendor: Rubicon Communications

Description

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

The vulnerability exists due to insufficient sanitization of user-supplied data in system_usermanager_addprivs.ph. A remote attacker can permanently inject 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

pfsense: 2.4.0 - 2.4.4_3

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External links
http://packetstormsecurity.com/files/157104/pfSense-2.4.4-P3-User-Manager-Cross-Site-Scripting.html
http://github.com/pfsense/pfsense/commit/3c1e53dabe966f27c9097a5a923e77f49ae5fffa
http://www.netgate.com/assets/downloads/advisories/pfSense-SA-20_06.webgui.asc

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