Loughlin Lavery
Which is better for vulnerability management? Which fits your strategy? Let’s discuss.
Security of Operational Technology can present a unique challenge compared with protecting IT. Legacy protocols, fragile endpoints, and stringent requirements for uptime make traditional vulnerability-management ineffective in most cases. Nozomi Networks, and Tenable both offer solutions that are unique in their approach. This post will explore the strengths of each solution as well as explain why costs often determine which option is chosen.
Importance of Vulnerability Management in Critical OT Environments
Operational Technology (OT) systems are crucial for industries like manufacturing, energy and transport, where uninterrupted operation is vital. These sectors face strict government regulation, such as Australia’s SOCI Act 2018, and must comply with recognised frameworks like AESCSF, ISO 27001 and the Essential 8. Although not legally required, adherence to these standards is now industry norm and often a prerequisite for doing business in the critical infrastructure sector.
Framework Adherence and Risk Management
Compliance with these frameworks centres largely around monitoring, maintaining, minimising and tracking risk. Vulnerability management stands out as a core component of this process, but it presents unique challenges within these industries.
Many OT environments are populated by devices, such as IoT devices, that cannot withstand routine scanning or patching. These circumstances necessitate the use of specialised tools designed for non-intrusive monitoring.
Operational Constraints and Cost Considerations
An additional layer of complexity is introduced by the typical segregation of OT environments from cloud workloads. Monitoring and scanning tools must therefore be hosted locally, which adds to the overall cost.
This is in addition to the already considerable expense of product licensing required to operate specialist solutions for vulnerability management in these critical sectors.
Where do Tenable and Nozomi come into the discussion?
Nozomi provides visibility and monitoring for industrial protocols at an IoT-scale, whereas Tenable manages enterprise-scale vulnerabilities across IT, cloud, and OT with safe discovery methods to minimise operational risks.
Tenable vs Nozomi - High level Capabilities Comparison
|
Category |
Nozomi Networks |
Tenable |
|
Primary Focus |
OT/IoT/ICS network visibility and threat/anomaly detection (network-based). |
Exposure/vulnerability management across IT attack surface; OT Security for converged OT/IT ICS environments. |
|
Core Products Referenced |
Guardian sensors; Vantage (SaaS); Central Management Console (CMC). |
Tenable One (platform); Tenable OT Security; Nessus / Nessus Network Monitor. |
|
Data Collection / Discovery |
Guardian sensors passively monitor and analyse network traffic; connect to mirrored ports/taps. |
OT Security uses Network Detection plus Active Query for asset inventory; IT uses active scans (e.g., Nessus). |
|
OT/ICS Posture |
Designed for OT/IoT; continuous monitoring and baseline-based (anomaly) detection. |
Designed for ICS protection without disrupting operations; hybrid discovery and configuration/vulnerability management. |
|
Threat & Anomaly Detection |
Builds a baseline and detects suspicious communications, malware transfer, unwanted operations, network changes. |
OT Security includes threat detection and mitigation features (alongside asset/vulnerability/configuration controls). |
|
Centralised Management |
CMC provides centralised OT/IoT security management; Vantage consolidates management in a SaaS app. |
Tenable One provides unified visibility and prioritisation across multiple Tenable products / attack surface. |
|
Passive Monitoring |
Guardian sensors are passive network monitors. |
Nessus Network Monitor (as part of Tenable OT) supports passive monitoring, protocol detection, OT/ICS asset discovery. |
How do these solutions work?
Nozomi Networks scanning solution's first operational step is to create a detailed list of IoT/OT assets. The next step is to monitor continuously for anomalies and suspicious patterns, while providing central management across multiple sites.
Tenable's IT/OT asset scanning technology includes agents, scans, and passive sensors. It provides risk scoring, compliance reporting, and prioritisation capabilities. It integrates seamlessly with patching/remediation work flows to provide enterprise visibility.
Benefits and Integration
Nozomi excels in industrial protocol visibility and behavioural contextual for safety-critical systems, whereas Tenable specialises in enterprise-scale vulnerability monitoring: standard workflows, reporting and across IT and OT environments.
Tenable and Nozomi are compatible but only in one direction; Nozomi will feed data on assets and vulnerabilities directly to Tenable allowing for comprehensive risk management and single pane of glass for monitoring.
Challenges and Costs
Nozomi's solution is quite expensive in comparison to Tenable's when compared to similar coverage in the same environment.
While the Nozomi organisation is specifically specialised in OT, Tenable has a greater overall technology market share. This is secured through more mature inbuilt integrations, greater customer base and broader platform features, allowing them to be more competitive on pricing.
In comparison, while Nozomi is designed specifically for Operational Technology (OT) environments, Tenable's OT solution offers enough coverage to meet compliance and budgetary restrictions.
Hidden Costs That You May Miss
When evaluating scanning solutions, it's important to factor in not only licensing costs but also the expense of hosting the infrastructure. OT environments require isolated networks and segmented systems, which results in additional hardware, CPU-based virtualisation licensing, and VM OS licenses. These all add up and can be easily missed when scoping an environment.
Ongoing renewals for operating systems and platforms further increase ownership costs. Additionally, each new scanner requires patching, monitoring, and log management, raising licensing costs across multiple other tools. The design phase is crucial for planning and scoping these costs out accurately, as costs can balloon quickly with unplanned components.
Plan for:
- Scanning solution licensing costs.
- Hardware for isolated network segmentation.
- OS licensing for scanning servers.
- Maintenance and repair of overhead.
- Patching.
- Monitoring (Infra + EDR).
Tenable offers scalability, flexible deployment, broad integrations, and a cost-effective licensing model. In contrast, Nozomi is pricier but specialises exclusively in OT, offering focused expertise. Pairing scanning solution licensing costs with expensive infrastructure hosting highlights the importance of cost savings.
Which one will you choose? Which one is right for you?
In my opinion, while both solutions meet the compliance framework need, Nozomi is the best option for real-time anomaly discovery and depth. While Tenable offers effective vulnerability management in IT and OT. As discussed earlier, their integration and scalability options are more appealing to many organisations.
In short for any potential customer or reseller, I would choose the solution that suits your needs and financial constraints.
Personally? I am partial to Tenable like many other people because it is familiar and well supported. Tenable's market share for will always be a boon when it comes to potential customers making a vendor decision - the price difference doesn’t hurt either.
As certified IT security experts, we can help you fortify your defences, uphold regulatory compliance, improve your company's security posture and proactively maintain your servers and networks to protect you from evolving cyber risks.
