OS Command Injection in pfsense

1) OS Command Injection

EUVDB-ID: #VU31200

Risk: High

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-16055

CWE-ID: CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Exploit availability: No

Description

The vulnerability allows a remote authenticated user to execute arbitrary code.

An authenticated command injection vulnerability exists in status_interfaces.php via dhcp_relinquish_lease() in pfSense before 2.4.4 due to its passing user input from the $_POST parameters "ifdescr" and "ipv" to a shell without escaping the contents of the variables. This allows an authenticated WebGUI user with privileges for the affected page to execute commands in the context of the root user when submitting a request to relinquish a DHCP lease for an interface which is configured to obtain its address via DHCP.

Mitigation

Install update from vendor's website.

Vulnerable software versions

pfsense: 2.4.0 - 2.4.3_1

External links

http://doddsecurity.com/190/command-injection-on-pfsense-firewalls/
http://www.pfsense.org/security/advisories/pfSense-SA-18_08.webgui.asc

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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