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Introduction:
The convergence of geopolitical conflict and operational technology (OT) has given rise to a new class of cyber-physical weapon: ZionSiphon. Discovered by Darktrace and first observed in the wild on June 29, 2025—immediately following the Twelve-Day War between Iran and Israel—this malware was specifically engineered to sabotage Israeli water treatment and desalination systems by manipulating chlorine levels and pressure controls. Although the version analyzed is riddled with logical errors and broken implementation code, its architecture reveals a concrete blueprint for how hacktivists and nation-state actors are actively experimenting with multi‑protocol ICS manipulation, USB‑based propagation, and politically charged physical‑impact payloads.
Learning Objectives:
- Analyze the geographic activation logic, USB propagation techniques, and incomplete ICS protocol exploits used in the ZionSiphon malware.
- Master a defensive toolkit of essential Linux/Windows commands for OT network discovery, Modbus/DNP3/S7comm interrogation, and anomaly detection.
- Implement segmentation, registry‑based persistence lockdowns, and one‑way data diode concepts to protect critical infrastructure from similar threats.
You Should Know:
- Geographic Activation & USB Propagation: The Two‑Stage Kill Chain
ZionSiphon implements a two‑condition activation mechanism: it first hardcoded three specific IPv4 ranges mapped to Israel—2.52.0.0–2.55.255.255, 79.176.0.0–79.191.255.255, and 212.150.0.0–212.150.255.255—and then checks for water‑treatment–specific process names and directory paths. Only when both conditions are satisfied does the payload begin scanning over Modbus, DNP3, and S7comm protocols.
If the checks fail, the malware triggers a self‑destruct routine to erase itself from disk, limiting forensic artifacts. However, due to logic errors in the XOR‑based country‑validation function, the wrong comparison length causes the check to always fail.
To spread across air‑gapped OT networks, ZionSiphon copies itself to removable USB drives as a hidden `svchost.exe` process and creates malicious shortcuts that launch the malware when clicked.
Below is a defensive command to monitor USB activity on a Windows‑based HMI:
Windows: List all USB storage devices attached (past + present) Get-WmiObject Win32_USBHub | Select-Object Name, DeviceID Enable USB device logging via Group Policy (Computer Configuration → Administrative Templates → System → Removable Storage Access) Enable: "All Removable Storage: Deny all access" Linux: Monitor USB event logs in real time sudo udevadm monitor --environment --udev | grep -i "usb"
- Breaking Down the OT Protocols: Modbus, DNP3 & S7comm
The most developed component in ZionSiphon is its Modbus module. It is capable of identifying Modbus‑speaking devices on the local subnet, reading holding registers, and writing malicious values to coils—the digital outputs that control physical equipment such as chlorine pumps. DNP3 and S7comm branches remain stubs with partially implemented protocol fingerprinting.
Step‑by‑Step Guide to OT Protocol Discovery & Hardening
Step 1: Passive OT Discovery with Nmap
Always avoid aggressive scanning in production OT networks. Use the following low‑intensity scan:
Linux: Gentle Nmap scan for common OT ports (Modbus=502, DNP3=20000, Siemens S7=102) sudo nmap -sS -Pn -T2 -p 502,102,20000 --script modbus-discover,s7-info,dnp3-info 192.168.1.0/24
This command uses `-T2` to slow down the scan and NSE scripts to retrieve device information without flooding the ICS network.『6†L7-L9』
Step 2: Mirror Traffic and Filter with Wireshark
Intercept OT traffic at a switch SPAN port:
Linux: Capture all Modbus, DNP3, and S7comm traffic to a PCAP file sudo tcpdump -i eth0 -s 0 -w ot_traffic.pcap -C 100 -G 3600 -W 24
Windows (Wireshark command line): Filter live OT protocols "C:\Program Files\Wireshark\tshark.exe" -i "Ethernet0" -Y "modbus || dnp3 || s7comm"
Wireshark’s display filter `modbus || dnp3 || s7comm` isolates industrial communications, enabling anomaly detection.『26†L20-L21』 Look for unexpected write commands or irregular register ranges.
Step 3: Interrogate Modbus Device Registers (Defensive Inventory)
Use the `mbpoll` tool (Linux) to read holding registers without altering state:
Read 10 holding registers from unit ID 1, address 0, using Modbus TCP mbpoll -m tcp -a 1 -t 3 -r 0 -c 10 192.168.1.100
This establishes a baseline of what values are normal during system operations. Any future deviation from these readings can indicate tampering via malware similar to ZionSiphon.
Step 4: Block Unauthorized OT Protocol Traffic with Windows Firewall
Since OT endpoints are often Windows‑based HMIs, restrict ports to only authorized PLCs:
Windows: Block all inbound S7comm (Port 102) except from the engineering workstation New-NetFirewallRule -DisplayName "Block_S7comm_From_IT" -Direction Inbound -Protocol TCP -LocalPort 102 -RemoteIP 192.168.100.5 -Action Allow
This enforces positive‑security model access: traffic is denied by default and explicitly allowed for specific OT management IPs only.『27†L37-L47』
3. Incomplete but Inevitable: The Prototype Effect
Dragos assessed the same sample and concluded it is a “poor attempt at generating OT malware using an LLM” where “the configuration file paths are fictional, likely LLM‑generated guesses.”『23†L16-L17』 However, even an incomplete version demonstrates a functional blueprint for privilege escalation, registry‑based persistence, USB propagation, and multi‑protocol scanning.
Although the Modbus parameter changes in this build would not actually alter chlorine levels, the threat actor proved they had researched specific Israeli water infrastructure components: Mekorot, Sorek, Hadera, Ashdod, Palmachim, and Shafdan. This shows that weaponized OT research is now within the reach of modest threat actors.
To defend, implement registry monitoring for persistence mechanisms on Windows hosts:
Windows: Enable auditing for registry key creation/modification (Run as Admin)
auditpol /set /subcategory:"Registry" /success:enable /failure:enable
Monitor Run/RunOnce keys for malware persistence
reg query HKLM\Software\Microsoft\Windows\CurrentVersion\Run
reg query HKCU\Software\Microsoft\Windows\CurrentVersion\Run
Real‑time monitoring using Sysmon
Sysmon64.exe -accepteula -i Install with default config
Get-WinEvent -FilterHashtable @{LogName='Microsoft-Windows-Sysmon/Operational'; ID=13} Filter registry events
- Defeating Geofencing: IP Range Hardening for OT Assets
The exact Israeli IP ranges hardcoded into ZionSiphon reveal that geographic filtering can be counteracted by careful network design. Even if your organization is not in the crosshairs, any Internet‑facing ICS or human‑machine interface (HMI) should be restrictively patched.
Step‑by‑Step Geographic Allow‑listing for an OT Management Jump Box
Step 1: Identify current public IP space in use by legitimate remote administrators.
Step 2: Implement strict scoping rules on the edge firewall or using `iptables` (Linux):
Linux: Allow inbound Modbus access ONLY from 10.0.0.0/8 internal range sudo iptables -A INPUT -p tcp --dport 502 -s 10.0.0.0/8 -j ACCEPT sudo iptables -A INPUT -p tcp --dport 502 -j DROP
Step 3: Apply geo‑IP blocking at the organizational perimeter to prevent downloads of malware payloads from foreign command‑and‑control servers. Use threat intelligence feeds to block IP addresses belonging to known malicious ranges.
5. Building a Resilient OT Forensic Toolkit
Because OT malware increasingly spreads via USB and modifies local configuration files, every defender should maintain a lightweight forensic kit to check for anomalous file changes or software additions.
- Establish a file integrity baseline for all HMI and engineering workstation binaries:
Linux: Generate SHA‑256 hashes for critical OT binaries
find /opt/plc_software /usr/local/bin -type f -exec sha256sum {} \; > baseline.txt
REM Windows: Use FCIV to hash SCADA executables fciv.exe C:\Program Files\SCADA.exe -sha1 -xml baseline.xml
- Set up a USB‑only honeypot folder: Create a decoy directory named after common Israeli infrastructure strings and monitor it with Sysmon event ID 11 for any access attempts (useful for early warning of USB‑propagating malware).
-
Monitor for fake `svchost.exe` processes appearing on removable drives:
Windows: Scan all connected drives for hidden "svchost.exe"
Get-PSDrive -PSProvider FileSystem | ForEach-Object {
Get-ChildItem $<em>.Root -Recurse -Force -ErrorAction SilentlyContinue |
Where-Object { $</em>.Name -eq "svchost.exe" -and $_.Attributes -match "Hidden" }
}
What Undercode Say:
- The blueprint for water‑poisoning attacks is already available to hacktivists. Even if ZionSiphon itself is broken, its design—geographic IP checks, USB propagation, Modbus manipulation—can be corrected and reused by future threat actors.
- OT protocol vulnerabilities are the new perimeter. Lack of authentication in Modbus, DNP3, and S7comm means any malware that gains network access can directly manipulate physical equipment. Segmentation and continuous traffic monitoring are no longer optional.
- Politically motivated malware is the new normal. The embedded strings supporting Iran, Palestine, and Yemen and the explicit reference to “Poisoning the population of Tel Aviv and Haifa” signal that nation‑state and hacktivist adversaries are weaponizing ICS cyber‑physical attacks without the need for sophisticated zero‑days.
Prediction:
By 2028, OT‑specific malware families will increase by 300% globally, with at least 15 successful water‑treatment or power‑grid manipulations using variants of USB‑propagation and Modbus exploits (as demonstrated by ZionSiphon). Threat actors will quickly adopt open‑source LLM tooling to correct the coding errors seen in this sample, leading to the first fully functional, automated OT sabotage malware that crosses over from unfinished prototype to real‑world weaponization. Consequently, international regulations will mandate air‑gapping for critical water infrastructure and real‑time cryptographic authentication for all legacy OT protocols—a standard that most facilities are currently unprepared to meet.
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Reported By: Hackermohitkumar Researchers – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
