A vulnerability, which was classified as critical, was found in pfSense up to up to 2.4.2 (Firewall Software). Affected is the function dhcp_relinquish_lease of the file status_interfaces.php. The manipulation as part of a POST Parameter leads to a command injection vulnerability. CWE is classifying the issue as CWE-77. The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The bug was discovered 08/28/2018. The weakness was disclosed 09/26/2018 (Website). The advisory is available at pfsense.org. This vulnerability is traded as CVE-2018-16055 since 08/28/2018. It is possible to launch the attack remotely. The successful exploitation needs a authentication. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1202 by the MITRE ATT&CK project.

By approaching the search of inurl:status_interfaces.php it is possible to find vulnerable targets with Google Hacking. The vulnerability scanner Nessus provides a plugin with the ID 119887 (pfSense 2.3.x <= 2.3.5-p2 / 2.4.x < 2.4.4 Multiple Vulnerabilities (SA-18_06 / SA-18_07 / SA-18_08)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Firewalls and running in the context r.

Upgrading to version bis 2.4.3 eliminates this vulnerability. A possible mitigation has been published even before and not after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (119887).

Productinfo

Type

• Firewall Software

Name

• pfSense

Version

• 2.4.0
• 2.4.1
• 2.4.2

License

• open-source

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CPE 2.2info

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