Top 20 Threat Scenarios & Playbooks for OT Security
A comprehensive list of 20 threat scenarios in OT security along with detailed descriptions and detection rules that can help identify and respond to these threats. This playbook-style table covers different types of attacks—from unauthorized access to insider abuse—with corresponding rules and indicators to alert security teams.
| # | Threat Scenario | Detailed Description | Detection Rules & Indicators |
|---|---|---|---|
| 1 | Unauthorized Remote Access Attempt | An attacker uses stolen or weak credentials to access OT networks remotely. | - Log Analysis: Monitor VPN/RDP logs for unusual login times, geolocation mismatches, and failed/successful login bursts. - User Behavior Analytics (UBA): Alert on deviations from normal remote access patterns. - Anomaly Detection: Trigger an alert when a remote session is initiated from an unusual IP or geographic region. |
| 2 | Malware/Ransomware Infiltration in OT Network | Malicious code is introduced into the OT network via compromised endpoints or phishing, potentially encrypting critical files. | - File Integrity Monitoring: Flag unauthorized changes or unexpected file modifications on critical OT systems. - Signature-Based Detection: Use updated antivirus and IDS/IPS signatures to detect known malware patterns. - Behavioral Analysis: Alert on abnormal process behavior (e.g., unexpected file encryption, rapid file modifications). |
| 3 | Abnormal SCADA/HMI Behavior | The HMI or SCADA system displays anomalous process values or commands, indicating possible tampering or malfunction. | - Threshold Alerts: Set bounds for process variables and trigger alarms when values exceed defined ranges. - Correlation Analysis: Compare current HMI data with historical baselines to detect deviations. - Alert on Unauthorized Commands: Monitor for non-standard or unexpected commands sent to the SCADA system. |
| 4 | PLC/RTU Unauthorized Configuration Change | An attacker or insider modifies the configuration or programming logic of Programmable Logic Controllers (PLCs) or Remote Terminal Units (RTUs). | - Configuration Baseline Monitoring: Regularly compare PLC configurations to a known-good baseline. - Change Audit Trails: Track and alert on changes to ladder logic or control parameters. - Integrity Checks: Use cryptographic checksums on PLC code; alert if checksums do not match the approved version. |
| 5 | Anomalous Network Traffic on OT Protocols | Unusual communication patterns in protocols like Modbus, DNP3, or OPC-UA may indicate unauthorized queries or command injections. | - Protocol Anomaly Detection: Monitor for atypical command frequencies or unexpected function codes in network traffic. - Deep Packet Inspection (DPI): Analyze packet payloads for commands that do not conform to the protocol’s normal behavior. - Traffic Baseline Analysis: Compare current traffic volumes and patterns to historical norms and raise alerts on significant deviations. |
| 6 | Physical Security Breach at a Critical Facility | Unauthorized physical access to OT equipment (e.g., control cabinets, RTUs) which might be used to inject malicious code or cause sabotage. | - Access Control Integration: Correlate physical access logs (from badge readers, CCTV) with network logs. - Anomaly Detection: Trigger alerts when physical access events coincide with unusual network activity. - Real-Time Alerts: Monitor for unscheduled maintenance or after-hours access in critical areas. |
| 7 | Insider Threat – Unauthorized OT Data Exfiltration | A legitimate user abuses their access privileges to export sensitive OT data for espionage or sabotage. | - Data Loss Prevention (DLP): Monitor for large or unusual data transfers from OT systems to external destinations. - User Activity Monitoring: Track privileged user actions and correlate with data movement. - File Transfer Alerts: Alert when sensitive OT files are copied to removable media or cloud storage without authorization. |
| 8 | Detection of Known OT Cyberattack Signatures | Indicators of compromise (IOCs) from malware like Stuxnet, Triton, or Industroyer are detected in the network. | - Signature-Based IDS/IPS: Implement updated signatures for known OT malware variants. - Hash & File Comparison: Compare executable hashes and file names against a database of known OT threats. - Behavioral Correlation: Look for specific command sequences or network patterns associated with historic OT attacks. |
| 9 | Unexpected Shutdown of Industrial Control Systems | Critical OT devices suddenly go offline or report abnormal status, possibly due to cyber manipulation or hardware faults. | - Heartbeat Monitoring: Alert when heartbeat or status signals from devices (PLCs, RTUs) are lost. - Event Correlation: Correlate unexpected shutdown events with recent configuration changes or unauthorized access alerts. - Redundancy Checks: Trigger alerts when backup systems are activated unexpectedly. |
| 10 | Compromise of Safety Instrumented Systems (SIS) | Unauthorized commands or logic changes in SIS can disable safety functions, leading to dangerous conditions. | - SIS Integrity Monitoring: Implement real-time monitoring of SIS logic changes and compare against approved configurations. - Alert on Anomalous Commands: Detect and alert if commands that disable emergency shutdowns are issued. - Forensic Logging: Maintain detailed logs of SIS events and correlate anomalies with potential intrusions. |
| 11 | Supply Chain Compromise of OT Software/Hardware | Malicious modifications to vendor-supplied software or firmware that can later be used to compromise OT systems. | - Digital Signature Verification: Check the authenticity and integrity of software/firmware updates before installation. - Vendor Audit Logs: Monitor and alert on discrepancies in vendor-supplied packages. - Baseline Comparison: Compare new software versions against established baselines. |
| 12 | Unauthorized Use of Insecure Remote Access Protocols | Use of unencrypted or legacy remote access protocols (e.g., Telnet, RDP without MFA) to gain access to OT systems. | - Protocol Monitoring: Alert when insecure protocols are used to access sensitive OT systems. - Encryption Verification: Check for the use of TLS/SSH on remote sessions and flag non-compliant connections. - Access Pattern Analysis: Monitor for abnormal remote access sessions, particularly outside normal operating hours. |
| 13 | Denial of Service (DoS) Attack Against OT Devices | Overwhelming network traffic or device-specific attacks causing resource exhaustion and loss of service. | - Traffic Volume Thresholds: Set alerts for sudden spikes in traffic volume targeting OT devices. - Rate Limiting & Anomaly Detection: Monitor connection rates and packet sizes for anomalies. - Device Performance Monitoring: Alert if OT device performance degrades beyond predefined thresholds. |
| 14 | Lateral Movement Across OT Networks | Attackers move laterally from one compromised system to another within the OT network to escalate privileges or expand access. | - Network Flow Analysis: Track inter-device communication patterns and alert on unusual lateral connections. - User Session Correlation: Monitor for sessions that access multiple OT devices in a short timeframe. - Segmentation Violation Alerts: Detect and alert if traffic crosses defined OT network boundaries without authorization. |
| 15 | OT System Misconfiguration | Unintentional or malicious misconfiguration of OT systems that leads to vulnerabilities or operational issues. | - Configuration Compliance Scanning: Regularly scan OT devices against configuration baselines. - Change Management Alerts: Trigger alerts when configuration changes occur outside approved windows. - Automated Policy Checks: Use tools to verify that systems meet security best practices and compliance standards. |
| 16 | Data Manipulation or Command Injection in SCADA Systems | Attackers inject false data or commands into SCADA systems to disrupt operations or cause unsafe conditions. | - Command Validation: Monitor SCADA command sequences and validate against expected operational parameters. - Data Integrity Checks: Implement checksums or hash comparisons on critical data streams. - Anomaly Detection: Alert on command sequences that deviate significantly from historical patterns. |
| 17 | Unauthorized Firmware Update on OT Devices | Malicious firmware updates may be pushed to devices like PLCs or RTUs, altering their functionality. | - Firmware Integrity Monitoring: Check digital signatures and hashes of firmware updates. - Update Event Logging: Alert when a firmware update occurs outside of scheduled maintenance windows. - Version Baseline Verification: Compare firmware versions against a known-good baseline and flag discrepancies. |
| 18 | Advanced Persistent Threat (APT) Activity | Long-term, stealthy compromise of OT networks by sophisticated adversaries to gather intelligence or prepare for future attacks. | - Behavioral Analytics: Use machine learning to identify subtle changes in device behavior over time. - Long-Term Log Correlation: Aggregate logs to detect low-and-slow attacks that gradually escalate privileges. - Threat Hunting: Conduct proactive searches for indicators of compromise (IOCs) linked to known APT groups. |
| 19 | Exploitation of Unpatched Vulnerabilities in OT Devices | Attackers exploit known vulnerabilities (e.g., unpatched CVEs) in OT devices and systems. | - Vulnerability Scanning: Regularly scan the OT network for known vulnerabilities. - Exploit Detection: Monitor network traffic for exploit attempts against specific CVEs. - Patch Compliance Monitoring: Alert if devices are not updated to the latest security patches. |
| 20 | Insider Abuse of Privileged Access | An insider misuses their elevated access to perform unauthorized actions or extract sensitive data. | - User Behavior Monitoring: Track and analyze the activity of privileged accounts, including unusual login times or resource access. - Access Log Correlation: Alert when a privileged user performs actions that are inconsistent with their typical responsibilities. - Segregation of Duties: Monitor for simultaneous access to conflicting systems or functions and enforce role-based restrictions. |
Recap
- Layered Detection: Combining signature-based, behavioral, and anomaly detection methods is essential for a robust OT security defense.
- Correlated Alerts: Cross-referencing alerts from IT, OT, and physical security systems enhances the detection of complex, multi-vector threats.
- Regular Baseline Updates: Establishing and continuously updating operational baselines for OT environments is critical to detecting deviations.
- Integration with Incident Response: Effective detection rules must feed directly into an incident response plan, ensuring that alerts lead to prompt and appropriate actions.
This comprehensive list provides a detailed starting point for designing and implementing detection rules tailored to the OT environment. Each scenario is paired with actionable rules that, when integrated into a Security Information and Event Management (SIEM) system or dedicated OT IDS/IPS, can help organizations quickly identify and mitigate threats.
#CPS #OT #XIoT #IoT #IIoT #IoMT #CPSSecurity #OTSecurity #IoTSecurity #CPS보안 #OT보안 #IoT보안
Comments
Post a Comment