Robustness Agent Message Filtering for ICS Intrusion Containment

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Solution Overview

Problem

Industrial control systems face significant security challenges due to the inability to effectively detect and prevent malware and unauthorized access, particularly in large and complex networks, where traditional security features like firewalls and antivirus software are insufficient against zero-day viruses and can impede operational activities.

Innovation Solution

A communications network threat detection system utilizing robustness agents that analyze and filter messages at network nodes, allowing or blocking messages based on predetermined characteristics, and implementing volume filtering to detect and mitigate potential intrusions, thereby preventing infected nodes from propagating malicious activity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional security features like firewalls and antivirus software are used, then basic network protection is provided, but they are insufficient against zero-day viruses and can impede operational activities

Engineering Contradiction:
Improvenetwork securityVSAvoidoperational activities
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system segments network traffic analysis into multiple components: a robustness agent that monitors message volumes and patterns, a syntax filter that analyzes message structure, and a volume filter that counts messages. Each component handles a specific aspect of security analysis, allowing comprehensive protection without overwhelming the system and minimizing impact on operational activities.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The robustness agent performs preliminary analysis of network messages by establishing baseline characteristics of normal traffic and comparing incoming messages against these baselines. This preliminary filtering identifies suspicious patterns before they can execute malicious payloads, blocking threats proactively while allowing legitimate traffic to pass through without interruption.

Inventive Principle:
Principle #10Preliminary action

2Difficulty of detecting and measuring

If comprehensive message analysis and filtering is implemented, then detection of intrusions is improved, but system complexity increases

Engineering Contradiction:
Improveintrusion detectionVSAvoidsystem complexity
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The intrusion detection system is divided into distinct modular components: the robustness agent for baseline comparison, the syntax filter for structural analysis, and the volume filter for quantity monitoring. Each module performs a specific function and can be independently configured, maintained, and updated, reducing overall system complexity while maintaining comprehensive detection capabilities.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The robustness agent acts as an intermediary between the network traffic and the filtering mechanisms. It establishes baseline characteristics of normal traffic and uses these baselines to guide the syntax and volume filters, enabling intelligent detection without requiring complex rule sets in each filter component.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If message filtering based on predetermined characteristics is applied, then malicious messages are blocked, but legitimate messages may be incorrectly filtered

Engineering Contradiction:
Improvemalicious messagesVSAvoidlegitimate message delivery
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The system implements feedback mechanisms where the robustness agent continuously monitors network traffic patterns and adjusts baseline characteristics based on observed legitimate communications. When new legitimate message types are identified, the baseline is updated to include them, preventing false positives while maintaining protection against malicious messages that deviate from established patterns.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The filtering system dynamically adapts to changing network conditions by continuously updating baseline characteristics of legitimate traffic. The robustness agent learns from observed communications and adjusts filtering thresholds and patterns in real-time, allowing the system to accommodate new legitimate message formats while maintaining protection against evolving threats.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS11363035B2Configurable robustness agent in a plant security system
Publication Date: 2022.06.14 FISHER ROSEMOUNT SYST INC
  • US11363035B2 patent drawing
  • US11363035B2 patent drawing
  • US11363035B2 patent drawing

AI summary

A communications network security system includes a robustness agent that operates within a communications interface of a device at one or more nodes of the network to analyze and filter messages coming from or going onto the network. At each of the nodes, the robustness agent determines one or more sets of message characteristics associated with each of the messages passing through the agent, and the agent is configured to allow certain types of messages (e.g., messages with certain predetermined sets of characteristics) to be passed through the agent, prevent messages with other predetermined characteristics from being passed through the agent, such as by halting (discarding or filtering) these messages, and/or passes still other messages having other sets of message characteristics to a volume filter to be counted. The volume filter counts the number of messages with a particular set of message characteristics and passes these messages if the number of these detected messages over a particular period of time is less than a particular threshold, and filters these messages if the number of counted messages is greater than a particular threshold over a particular period of time.