Threat Intelligence / ZionSiphon

ZionSiphon Attack Path

How a USB drive becomes physical consequence

The malware did not arrive through a phishing email or an exposed service.

It arrived on a USB drive someone plugged in.

From that moment, it moved through systems that looked entirely normal until it reached the process layer.

The Attack Path

Seven phases. Click any node to inspect it. Step through with the controls below. The path builds as the attack progresses — watch the current escalate from trusted blue to amber to consequence red.

USB Drive Workstation Persistence Validation OT Network Protocol Layer Process Impact
💾
USB Entry
💻
Workstation
🔒
Persistence
✓
Validation
🌐
OT Recon
⚡
Modbus
⚠
Consequence
Phase 1 of 7
What Happens

Why It Matters

Defender Signal

—

IOC Hunt Checklist

File & Network Indicators
0 / 4 confirmed
✓
07c3bbe60d47240df7152f72beb98ea3...SHA-256 — confirmed ZionSiphon sample
✓
2.52.0.0 – 2.55.255.255Hardcoded target IP range — not a global safety boundary
✓
79.176.0.0 – 79.191.255.255Hardcoded target IP range
✓
212.150.0.0 – 212.150.255.255Hardcoded target IP range
Host-Based Indicators
0 / 7 reviewed
✓
svchost.exe from %LOCALAPPDATA%Masquerade persistence — not running from System32
✓
HKCU\...\Run: SystemHealthCheckDirect ZionSiphon persistence indicator
✓
%TEMP%\target_verify.logMalware executed and attempted validation even if payload failed
✓
%TEMP%\delete.batCleanup artifact from self-destruct routine
✓
PowerShell RunAs from non-interactive parentUAC elevation mechanism
✓
LNK shortcuts created on removable drivesPropagation mechanism for USB spread
✓
Appended entries in DesalConfig.ini / ROConfig.iniOT config file tampering indicators

Detection Playbooks

💻

svchost.exe Outside System32

Endpoint — highest priority detection, catches active sample

▼
  • Alert on any svchost.exe process where the image path contains AppData, LocalAppData, Temp, or a removable drive letter
  • Legitimate svchost.exe runs exclusively from %SystemRoot%\System32\ under SYSTEM, LOCAL SERVICE, or NETWORK SERVICE accounts
  • A user-context svchost.exe from AppData is a near-certain malware indicator
Sample SIEM Query — svchost Masquerade process_name="svchost.exe" NOT process_path CONTAINS "\\Windows\\System32\\" | table _time, host, user, process_path, parent_process | sort -_time
Sigma YAML — Rule 1 (Critical) 
title: ZionSiphon - svchost.exe Masquerade
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\svchost.exe'
    filter_legit:
        Image|startswith:
            - 'C:\Windows\System32\'
            - 'C:\Windows\SysWOW64\'
    condition: selection and not filter_legit
tags: [attack.defense_evasion, attack.t1036.005]
level: critical
🔑

HKCU Run Key — SystemHealthCheck

Registry — direct ZionSiphon persistence indicator

▼
  • Alert on creation of HKCU\Software\Microsoft\Windows\CurrentVersion\Run with value name SystemHealthCheck
  • This is a hardcoded indicator specific to the analyzed ZionSiphon sample
  • Any match should be treated as high-confidence and investigated immediately
Sample SIEM Query — Registry Persistence event_type=registry_set registry_key CONTAINS "\\CurrentVersion\\Run" registry_value_name="SystemHealthCheck" | table _time, host, user, registry_key, registry_value_data
Sigma YAML — Rule 2 (Critical) 
title: ZionSiphon - Hardcoded Run Key Persistence
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|contains: '\CurrentVersion\Run'
        TargetObject|endswith: '\SystemHealthCheck'
    condition: selection
tags: [attack.persistence, attack.t1547.001]
level: critical
🛡

PowerShell UAC Bypass via RunAs Verb

Endpoint — elevation mechanism used by ZionSiphon

▼
  • Alert on PowerShell command lines containing Start-Process and -Verb RunAs launched from a non-interactive parent process
  • This indicates an application attempting to self-elevate through UAC rather than running with pre-granted privileges
  • In an OT workstation context, this is unusual and warrants immediate investigation
Sample SIEM Query — UAC Elevation process_name="powershell.exe" cmdline CONTAINS "Start-Process" cmdline CONTAINS "RunAs" parent_is_interactive=false | table _time, host, user, cmdline, parent_process
Sigma YAML — Rule 3 (High) 
title: ZionSiphon - PowerShell Self-Elevation
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\powershell.exe'
        CommandLine|contains|all:
            - 'Start-Process'
            - 'RunAs'
    filter_interactive:
        ParentImage|endswith:
            - '\explorer.exe'
            - '\cmd.exe'
    condition: selection and not filter_interactive
tags: [attack.privilege_escalation, attack.t1548.002]
level: high
💾

LNK Creation on Removable Media

File system — USB propagation mechanism

▼
  • Alert on .lnk file creation events where the target path is a removable drive volume (D:\, E:\, etc.)
  • ZionSiphon creates disguised LNK shortcuts to carry itself across USB media
  • Correlate with the presence of svchost.exe on the same drive for higher confidence
Sample SIEM Query — LNK on Removable Media event_type=file_create file_extension=".lnk" file_path REGEX "^[D-Z]:\\" | table _time, host, user, file_path, process_name
Sigma YAML — Rule 4 (High) 
title: ZionSiphon - USB Propagation LNK
logsource:
    category: file_event
    product: windows
detection:
    selection:
        TargetFilename|re: '^[D-Z]:\\.*\.lnk$'
    filter_user:
        Image|endswith: '\explorer.exe'
    condition: selection and not filter_user
tags: [attack.lateral_movement, attack.t1091]
level: high
🌐

TCP Burst to OT Protocol Ports

Network — OT network reconnaissance sweep

▼
  • Alert on a single source IP making rapid TCP connection attempts to multiple hosts on ports 502 (Modbus), 20000 (DNP3), and 102 (S7comm) within a short time window
  • ZionSiphon scans the local /24 subnet for accessible ICS devices before targeting them
  • A workstation initiating this sweep is a very high confidence indicator of OT sabotage tooling
Sample SIEM Query — OT Port Sweep dest_port IN (502, 20000, 102) | stats dc(dest_ip) as hosts by src_ip, _time span=60s | where hosts > 3 | table _time, src_ip, hosts
Sigma YAML — Rule 5 (High) 
title: ZionSiphon - OT Network Reconnaissance
logsource:
    category: network_connection
    product: windows
detection:
    selection:
        DestinationPort: [502, 20000, 102]
    condition: selection | count(DestinationIp) by SourceIp > 3
    timeframe: 60s
tags: [attack.discovery, attack.t1046]
level: high
⚡

Modbus FC06 Write to Registers 0–9 (OT Platform)

OT Protocol — requires industrial DPI with Modbus baseline

▼
  • Alert on Modbus function code 06 (Write Single Register) targeting registers 0 through 9 from a workstation process outside an authorized change window
  • ZionSiphon writes FC06 value of 100 to the chlorine dose register — a direct process manipulation attempt
  • This detection requires OT-aware monitoring with Modbus protocol deep packet inspection and a behavioral baseline
  • In a water environment, any unexpected FC06 write to low registers should be treated as a sabotage scenario
Sigma YAML — Rule 8 (Critical) OT Platform 
title: ZionSiphon - Modbus FC06 Process Manipulation
logsource:
    product: modbus
    service: protocol
detection:
    selection:
        function_code: 6  # FC06 Write Single Register
        register_address|lt: 10
    filter_maintenance:
        change_window_active: true
    condition: selection and not filter_maintenance
tags: [attack.impact, attack.t0836, attack.t0855]
level: critical
📊

Modbus FC03 Read Burst Across Multiple Hosts (OT Platform)

OT Protocol — discovery phase before manipulation

▼
  • Alert on a single source issuing Modbus FC03 (Read Holding Registers) requests to ten registers from address zero across multiple destination IPs in rapid succession
  • This is ZionSiphon's register discovery pattern — it reads before it writes to identify the chlorine dose register
  • This detection requires OT network visibility with Modbus protocol parsing
Sigma YAML — Rule 9 (High) OT Platform 
title: ZionSiphon - Modbus FC03 Register Discovery
logsource:
    product: modbus
    service: protocol
detection:
    selection:
        function_code: 3  # FC03 Read Holding Registers
        start_address: 0
        quantity: 10
    condition: selection | count(dest_ip) by src_ip > 2
    timeframe: 30s
tags: [attack.discovery, attack.t1046]
level: high

Key Takeaways

Takeaway 01

Air Gaps Don't Stop USB

ZionSiphon's propagation mechanism is specifically designed to cross air gaps through operational media use. Physical isolation is not a control against this vector. Media policy and workstation lockdown are.

Takeaway 02

The Flaw Is Temporary

The country validation logic error that prevents current activation is a single correctable line of code. The Modbus capability, USB propagation, and masquerade persistence are all functional. This is a draft weapon.

Takeaway 03

Process-Aware Tooling Is Accessible

ZionSiphon proves that actors outside top-tier nation-state programs can now build malware that understands OT protocols and targets physical process parameters. The barrier has dropped significantly.

Read the full intelligence report including MITRE mapping, complete IOC table, and mitigation recommendations.

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