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Enhancing Network Security by Combining VLAN and NDR
While VLANs provide a robust solution for segmenting networks, reducing congestion and improving security, they can be compromised. If a device on the network is physically compromised, VLANs cannot detect or respond to internal or sophisticated threats. This leaves room for lateral movement by cybercriminals.
The solution? Adding a Network Detection and Response (NDR) solution. NDR actively monitors and protects network communications, even within VLANs. By combining network segmentation with advanced detection capabilities and proactive threat response, companies significantly strengthen their cybersecurity posture.
But what exactly are the limitations of VLANs? How do NDR solutions address these shortcomings? And what are the best practices to maximise network security?
Let’s dive in.
What is a VLAN?
A Virtual Local Area Network (VLAN) is an independent virtual network. It segments a physical network into distinct logical sub-networks, offering better traffic management and increased security. Each VLAN groups devices as if they were connected to the same local network, even if physically dispersed.
One of the main benefits of VLANs is their ability to isolate groups of users or services. This limits the spread of threats and improves confidentiality.
For example, a company’s finance department can be separated from the IT department. This prevents unauthorised communication between them. VLANs also reduce network congestion by limiting broadcast traffic within each segment, improving overall performance.
VLAN limitations in terms of cybersecurity
While VLANs allow segmentation of a physical network into logical sub-networks, they do have certain limitations.
Limited isolation
Although VLANs allow segment isolation, this isolation relies on software configurations. These can be bypassed by attacks such as VLAN hopping.
In this type of attack, a cybercriminal injects malicious packets that cross the logical barriers between VLANs, thus accessing unauthorised segments. This vulnerability can be exploited when switch configurations are weak or poorly secured.
Lack of active monitoring
VLANs do not include mechanisms to detect or respond to malicious activity. They are limited to logical segmentation only.
If an internal threat, such as malware or ransomware, enters a VLAN, it can move freely within the segment or between poorly configured segments. Without monitoring tools like Network Detection and Response (NDR), these threats often go unnoticed.
Lack of micro-segmentation
VLANs offer macro-level segmentation. But they lack the granularity needed to effectively isolate communications between IT assets. Once ransomware compromises a segment, it can easily move to other systems within the same segment. This is known as lateral movement.
The contribution of NDR solutions
A Network Detection and Response solution is a cybersecurity technology that analyses network traffic in real time. It detects abnormal behaviour, advanced threats, and malicious activity. Thanks to artificial intelligence and machine learning, it identifies attacks often invisible to traditional tools.
In this way, an NDR solution complements VLAN segmentation. It provides visibility into both inter-VLAN and intra-VLAN traffic, quickly detecting and responding to threats that bypass VLAN logical isolation.
Detection of advanced threats
Unlike traditional tools that rely solely on signatures, NDR solutions can identify sophisticated attacks that evade classic systems.
For example, fileless malware, attackers’ lateral movement within the network, or communication between compromised systems and command and control (C2) servers can all be detected by AI. AI analyses network behaviour in real time.
In other words, NDR can identify malicious behaviours by analysing telemetry data—that is, information about network activity. Unlike approaches that need several months of historical data to detect anomalies, these solutions can immediately detect threats. They rely only on telemetry from a control point, without needing prolonged behavioural analysis.
Increased network visibility
NDR solutions offer visibility across all network segments, including VLANs, which are often seen as low-visibility zones. By monitoring traffic flows between segments, they detect subtle anomalies. For instance, an unusual flow between a user VLAN and a sensitive VLAN might indicate compromise or malicious activity.
Fast incident response
Once a threat is detected, NDR solutions generate detailed alerts. These include information about the source, the target, and the nature of the suspicious activity. This allows security teams to react quickly by isolating affected segments or blocking specific communications, thus reducing the impact of an incident.
Furthermore, by integrating into the customer’s ecosystem (e.g. firewalls, EDR, etc.), the NDR can directly send a command to block suspicious traffic.
Best practices for implementing NDR in a VLAN environment
To effectively integrate an NDR solution in a VLAN-segmented network, consider the following:
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Strategic probe placement: Install NDR probes at critical network points, such as core switches. This ensures full visibility over traffic flows, including communications between VLAN segments.
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Integration with existing tools: Ensure the NDR works in harmony with other security solutions, such as Security Information and Event Management (SIEM) systems and endpoint detection (EDR) tools. Smooth integration improves alert correlation and response coordination.
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Access configuration: Adjust access policies so the NDR can effectively monitor network traffic. Activate access only for necessary segments, applying strict controls to avoid unintentional exposure.
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Staff training: Train your IT and security teams in using the NDR solution. They should be able to interpret alerts, distinguish real threats from false positives, and respond quickly in case of an incident. Proper training reduces human error and increases the tool’s effectiveness.
Strengthen your network security with Custocy’s NDR solution
Although VLANs are useful for segmenting networks and limiting threat spread, they alone do not guarantee complete security. Their effectiveness depends on strict configurations. But without active monitoring, attackers can exploit them, especially via lateral movement or VLAN hopping.
NDR solutions fill this gap. They provide continuous monitoring and proactive detection of malicious activity, even within VLANs. By enhancing network visibility and enabling fast incident response, they significantly improve an organisation’s cybersecurity posture.
Custocy and its partners support you in deploying a sovereign NDR solution tailored to your needs and constraints. Protect your critical systems and reduce the risk of compromise.
Contact us today to strengthen your network security and anticipate cyber threats.
