One of the most crucial safeguards for Operation Technology (OT) is the ability to detect cyber threats within OT networks in real time. Given the importance of availability and uptime, the ability to quickly detect potential threats and respond with appropriate measures is highly stressed. Detection and prevention strategies must be carefully crafted for OT Networks to avoid excessive false positives and potentially unnecessary disruptions.
Let’s look at the key characteristics of a threat detection program:
- Tracking key assets and data: Automatically tracking and assigning value to all OT assets, including hardware, software, and network devices.
- Logging and Auditing: Comprehensive logging of all activities and events for auditing and forensic analysis in a centralized system.
- Alerting and Response: It includes alerting mechanisms and a well-defined incident response plan to respond quickly to detected threats.
- Threat Intelligence: To stay informed about emerging threats specific to OT environments, the program integrates threat intelligence feeds and data from various sources.
- Continuous Monitoring: The program entails real-time monitoring of the OT network to detect anomalies and potential threats.
Utilize your Asset Inventory to scope your Detection System
Organizations need to first determine what their critical assets are and then prioritize resources accordingly, such as log retention, and frequency of log reviews making informed decisions about which log data should be forwarded to their centralized logging solution.
- Identify key assets and data
- Assess common threat vectors
- Review industry best practices
What logs should be monitored?
Not all unusual events point to malicious activity or demand further investigation. Here are some examples of events that should be monitored on a regular basis, according to the NIST 800-82r3 Publication:
Information Events
- Account lockouts
- Unauthorized creation of new user accounts
- Unanticipated remote login activities
- The deliberate erasure of event logs
- Event logs becoming unexpectedly saturated with data
- Antivirus or Intrusion Detection System (IDS) alerts
- Intentionally disabling antivirus software or other security controls
- Requests for information on the system or its architecture
Operational Events
- Unauthorized configuration changes
- Unauthorized use of system patches
- Inadvertent system shutdowns
Networking Events
- Data transmission that was unexpected
- Significant network activity
- Devices that are not permitted to be used.
- Data transmissions that are unauthorized
Centralize and Analyze your Logs.
Once you’ve determined your key assets, and the logs to collect, the next step is to send and collect those logs in a centralized log system or a SIEM (Security Information and Event Management). Logs can then be correlated across different systems. These solutions can also provide additional information to help parse and reduce noise on logs with tactics such as threat intel, alert baselining, and behavioral analysis.
- Known threats: Threat intel or Signature-based detection can help detect previously known exploits by identifying unique signatures within the code of each exploit.
- Unidentified threats: Threats that have not previously been observed in real-world scenarios but can sometimes be identified by threat intel or behavioral analysis.
- Anomalies: Traffic in OT networks is more predictable than traffic in IT networks. This predictive nature can be used to create accurate baselines and anomaly alerting.
Continuous Monitoring & Improvement:
To assess the effectiveness of protective measures, organizations should include ongoing surveillance as part of their risk management strategy. Establishing a routine for assessing the achievement of desired outcomes should be considered.
- Data Collection: Threat intelligence involves gathering data from various sources, such as security feeds, government agencies, industry-specific organizations, security vendors, and internal network monitoring systems. This data includes information on known vulnerabilities, attack patterns, malware signatures, and indicators of compromise (IOCs).
- Analysis: Once the data has been collected, it is analyzed to identify emerging threats, trends, and patterns that may pose risks to OT environments. Analysts evaluate the information’s relevance and credibility to determine its potential impact on the organization’s OT systems.
- Alerting/Detection: Threat intelligence feeds and indicators of compromise (IOCs) are integrated into security monitoring systems such as Intrusion Detection Systems (IDS) or Security Information and Event Management (SIEM) solutions. This allows for the detection of threats and suspicious activities in the OT environment in real-time.
- Incident Response Planning: Threat intelligence is used to inform incident response plans. Organizations can prepare for specific threats by creating playbooks and response procedures tailored to potential attacks using intelligence.
- Feedback & Monitoring Loop: Continuous monitoring of the OT environment and incident response feedback are used to refine and improve threat intelligence practices over time.
Final Thoughts
Cybersecurity threat detection is critical in operational technology (OT) and industrial control systems (ICS). Organizations require a robust OT cyber detection program that prioritizes real-time threat identification and response. This program includes key components such as asset tracking, alerting and response, threat intelligence integration, continuous monitoring, and thoughtful data organization. Organizations can effectively protect their OT networks by determining which events to monitor and distinguishing known from unknown threats. In this ever-changing digital landscape, ongoing surveillance and the integration of threat intelligence are critical for proactively strengthening and refining cybersecurity defenses.
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