Unmanaged Devices Cybersecurity: How to Regain Control Over Your Biggest Cyber Risk

Unmanaged devices have quietly become the number one blind spot in enterprise cybersecurity. As connected devices multiply across hospitals, factories, energy grids, vehicles, and corporate networks, driven by the rapid adoption of the Internet of Things (IoT) and operational technology (OT), many are joining environments without identity, authentication, or security controls in place.

According to Device Authority, one-third of all data breaches now involve an IoT device, and over 50% of connected devices contain critical vulnerabilities that attackers can easily exploit by exploiting vulnerabilities. Many of these devices lack basic security controls and fall outside the scope of traditional security tools, creating significant security risks for organizations. Vulnerabilities in unmanaged devices can directly impact business operations, potentially disrupting workflow and operational continuity.

Attacks such as the Eleven11Bot botnet prove just how easily adversaries can weaponise unmanaged devices at scale — often without organisations even knowing those devices were present on their network. Unmanaged devices represent a significant threat by expanding the attack surface of enterprise networks.

In this article, we break down why unmanaged devices are a rising threat, how they evade traditional defences, and what security leaders must do to regain visibility and control in 2025, including the need to gain visibility into all unmanaged assets.

What Are Unmanaged Devices?

Unmanaged devices are assets that:

• Are connected to your network, including network devices that are not managed
• Are not enrolled into IT or security tools
• Lack proper identity, authentication, or certificates
• Are not monitored for vulnerabilities or configuration drift
• Often ship with vendor-locked firmware or unchangeable defaults

Examples include:

• Smart sensors, PLCs, and industrial controllers
• Legacy medical devices
• Building management systems (HVAC, security panels)
• Consumer-grade IoT used in corporate settings
• Temporary contractor devices
• Vehicle components (ECUs, telematics units)
• AI-driven cameras and edge devices
• Specialized devices, such as industrial, medical, or financial devices

Unmanaged IoT devices are especially prevalent in enterprise environments. Due to their lack of security controls and limited visibility, these unmanaged IoT devices introduce significant cybersecurity risks, increasing the likelihood of breaches and operational disruptions.

These devices often cannot run traditional agents, making them invisible to standard security tools.

Unlike unmanaged devices, managed devices are typically accounted for in IT inventories and possess stronger security measures, making them easier to secure and monitor.

Why Unmanaged Devices Are So Dangerous

1. They Have No Trusted Identity

Most unmanaged devices:

• Ship with default credentials
• Have no unique cryptographic identity
• Use insecure communication protocols
• Cannot authenticate themselves on the network
• Do not typically support or enforce multi-factor authentication

This makes them perfect entry points for attackers.

2. They Are Easy to Hijack

Botnets such as Eleven11Bot exploit vulnerabilities in unmanaged devices, as attackers exploit:

• Hard-coded passwords
• Unpatched firmware
• Open ports
• Weak or nonexistent encryption

Once compromised, unmanaged devices can be used for:

• Lateral movement (attackers often use compromised unmanaged devices to move laterally toward high value targets, such as financial servers or medical equipment)
• Data exfiltration
• Disrupting critical systems
• Ransomware staging
• DDoS attacks
• Stealing sensitive data

The scale of these botnets shows how quickly unmonitored devices can be used against their owners. Attackers exploit these vulnerabilities to gain access and steal sensitive data.

3. They Blend Into Critical Environments

Unmanaged devices often live inside core operational environments:

• OT (Industrial) (including industrial systems and OT devices)
• Medical
• Energy
• Utilities
• Automotive
• Smart buildings
• Sensitive systems such as financial servers and patient data repositories

Poor network segmentation can allow unmanaged devices to coexist with sensitive systems on the same network segment, increasing the risk of unauthorized access. In these environments, unmanaged devices connect to the network in ways that may not be fully monitored or controlled, potentially creating pathways for attackers to access critical systems.

Security teams can’t simply shut them down without risking operational disruption, making them even harder to control. These environments often include industrial sensors that are critical to operations, and protecting sensitive systems within these networks is essential to prevent breaches and maintain operational continuity.

4. Traditional IT Security Tools Can’t See Them

Because they cannot host agents, unmanaged devices fall outside:

• EDR
• MDM
• SIEM ingestion
• Vulnerability scanners
• Network access control systems

Traditional security approaches are often inadequate for device security in these environments, as they cannot address the unique risks and limitations of unmanaged and IoT devices. Many unmanaged OT devices run outdated or vulnerable operating systems, further increasing their susceptibility to cyberattacks. This results in significant security challenges, including increased vulnerabilities and difficulty in monitoring and managing these assets.

This leaves entire networks running on trust-by-default, a direct violation of Zero Trust guidance from NIST, CRA, and EO 14028.

How Unmanaged Devices Enter Your Network Without Detection

Shadow IoT

Employees connecting unauthorised personal devices, such as smart devices, smart TVs, and security cameras, which are typical examples of shadow IoT.

Security cameras are often deployed to enhance physical security, but if unmanaged, they can introduce significant cybersecurity risks.

Vendor-locked OT equipment

Tools that cannot be updated or modified. Many IoT deployments rely on vendor-locked equipment that cannot be updated or modified after installation. This is especially common in operational technology (OT) environments, where devices are integral to critical infrastructure such as manufacturing plants, utilities, and healthcare systems. These OT devices, once deployed, often remain in service for years without updates, making them attractive targets for attackers seeking to disrupt essential services.

Legacy medical equipment

Outdated but operational devices still used in clinical workflows pose significant risks in healthcare environments, particularly due to the potential exposure of sensitive data.

Third-party contractor equipment

Temporary assets that bypass normal controls.

Supply chain devices

Systems installed by integrators or OEMs without proper onboarding.

The result?
Most enterprises do not know how many connected devices they actually have, let alone whether they’re secure.

Why 2025 Regulations Require Immediate Action

Government frameworks such as:

• NIST IoT standards
• The EU Cyber Resilience Act (CRA)
• Executive Order 14028

are driving the adoption of IoT security best practices across industries, emphasizing the need for comprehensive protection strategies and regulatory compliance.

now require:

• Real-time device visibility
• Strong identity for every device
• Enforced authentication and policy control
• Automated credential management
• Continuous monitoring of device activity and network security

Unmanaged devices cannot meet these requirements without a dedicated device identity platform.

The Only Reliable Solution: Automated Visibility + Identity + Policy Control

To eliminate unmanaged device risk, organisations need three things:

1. Agentless Device Discovery

The first step is knowing what’s on your network. Managing device security throughout the entire device lifecycle is essential, beginning with discovery and continuing through provisioning, configuration, maintenance, monitoring, and recovery to ensure comprehensive protection.

Tools like Device Authority’s Discovery Tool automatically:

• Scan networks
• Identify unknown or unmanaged devices
• Analyse device type, metadata, and firmware
• Flag vulnerabilities and weak configurations
• Detect suspicious activity
• Provide risk-based scoring

The July 2025 newsletter highlights how the tool identifies connected devices, reveals potential risks, and seamlessly onboards them into Zero Trust workflows .

2. Automated Identity Assignment

Every device must be issued a:

• Unique cryptographic identity
• Secure certificate
• Verified trust anchor
• Policy-based role

Identity must be automated, as manual onboarding does not scale to thousands or millions of devices.

3. Continuous Zero Trust Enforcement

Once identity is established, organisations need:

• Automated certificate rotation
• Real-time device compliance checks
• Policy updates based on risk
• Automatic isolation of non-compliant devices
• Secure credential storage and provisioning

This is the core of KeyScaler 2025 — automated device trust that operates across IoT, OT, and edge environments.

How KeyScaler 2025 Eliminates Unmanaged Device Risk

KeyScaler 2025 introduces:

• AI-supported automation to detect anomalies and assess trust
• Agentless onboarding for legacy & vendor-locked devices
• End-to-end Zero Trust enforcement
• Automated PKI and certificate lifecycle management
• Policy-driven encryption and credential handling

Combined with agentless discovery, it transforms unmanaged devices from a security liability into a controlled, compliant, monitored asset. The solution also identifies and manages high risk IoT devices—such as outdated or poorly secured devices connected to corporate networks—helping prevent them from becoming entry points for attackers.

Industries Most at Risk from Unmanaged Devices

Healthcare

Unsecured medical devices expose patient safety and confidential data.

Industrial & OT

Connected PLCs, sensors and controllers can be hijacked to disrupt operations.

Automotive & Mobility

Non-compliant ECUs and telematics units expose manufacturers to WP.29 violations.

Energy & Utilities

Connected substations, meters and IoT sensors are targets for nation-state attackers.

Smart Buildings

HVAC, CCTV and physical access devices often run unpatched firmware.

Recommended Actions for CISOs in 2025

1. Conduct a network-wide device discovery scan
2. Assign cryptographic identity to every device
3. Automate certificate management
4. Implement Zero Trust policies for IoT/OT
5. Continuously monitor device behaviour and risk

This approach is now essential – not optional.

Final Thoughts

Unmanaged devices are no longer a hidden inconvenience; they are now the biggest threat surface facing modern organisations. With attackers increasingly targeting insecure IoT and OT assets, organisations must adopt automated, identity-first Zero Trust controls.

Solutions like KeyScaler 2025 and Device Authority’s Discovery Tool give security teams the visibility and enforcement they need to secure every device, even the ones they didn’t know existed.