Windows 10 End of Life: A Hidden Cyber Threat in Plain Sight

14 January 2026

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With Microsoft withdrawing support for Windows 10 operating systems (OS), users no longer receive security patches, feature updates or technical support. As a result, devices running on Windows 10 are now exposed to cybercrime.

Globally, one out of five devices still runs on Windows 10, and the number is much higher in Australia. As of late 2025, 34% of Australian businesses have not yet upgraded to Windows 11¹. This means their professional ecosystems remain compromised.

Why 'end of life' is a critical security vulnerability

When an operating system reaches end of life (EOL), it no longer receives security patches, bug fixes or technical assistance. Cyber criminals actively scan for such outdated systems, as the lack of regular security patches provides easy entry points for repeated exploitation.

Beyond security risks, legacy systems struggle to integrate with modern software, resulting in performance issues, downtime and operational bottlenecks that impact service delivery and customer experience.

In Australia, organisations covered under the Privacy Act and the Notifiable Data Breaches Scheme are expected to take reasonable steps to secure personal information. This task becomes more challenging when running unsupported systems.

A look back: Lessons from Windows 7 EOL

When Windows 7 support ended in 2020, many organisations delayed upgrading, assuming short-term risk was manageable. Within months, attackers began targeting Windows 7 systems on a large scale. It was an easy task for attackers because of known vulnerabilities in the unsupported operating systems.

Healthcare providers, local authorities and smaller organisations felt the impact most sharply, mirroring the dynamics seen in the 2017 WannaCry attack, which compromised over 200,000 Windows systems globally².

What can businesses do now?

Businesses are advised to migrate their systems to the latest operating systems through a safe and well-managed transition plan, including the following steps:

Knowing your assets

Create your current inventory of all devices still running on Windows 10. You can do penetration testing to pinpoint weak spots and prioritise transition.

Segment the network

Isolate high-risk systems from customer-facing technology and critical data flows. This shields your primary environment in the event of a breach.

Use layered cyber controls

Use firewalls, endpoint detection and response tools (EDR), multi-factor authentication (MFA) and behaviour-based monitoring to defend systems during migration, especially where legacy equipment cannot be replaced immediately.

Train your employees

Exploiting human error remains one of the easiest paths for attackers. Therefore, regular awareness training becomes important to reduce phishing success and improve incident reporting.

Review your cyber insurance policy

Some insurers are tightening conditions for legacy operating systems. Organisations may face reduced coverage, exclusions or higher premiums if they delay upgrades. During transition periods, review your policy limits, conditions and any additional support available.

It is also essential to have a cyber incident response plan in place, and a version specific to the business that can be used as a quick response plan in the event of an emergency.

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Organisations can take this as an opportunity to review broader cyber practices. For example, businesses can use tools such as Microsoft Copilot, behavioural analytics and automated threat detection to strengthen control over sensitive data. However, this requires the system to be built on supported and secure systems.

Proactive risk management is the first step in cyber protection

The Windows 10 EOL shift reinforces a core principle in cybersecurity: Prevention costs are less than the recovery costs. To act upon that, organisations can do the following:

Defend proactively

Strengthen their resilience by combining system upgrades with modern tools such as behavioural analytics and robust data security governance frameworks to support a safer digital environment.

Reviewing insurance cover

A strong cyber defence reduces exposure, but insurance provides the financial and operational support when incidents occur.

How can Gallagher help?

In the event of a cyber incident, breach or concern, having a trusted partner to help you manage it effectively is highly valuable. That's where the Gallagher cyber experts come in.

Our comprehensive policies provide coverage for:

Business interruption: Compensation for revenue lost during forced closures or downtime.
Incident response: Immediate access to expert investigators and forensic teams.
Data recovery: Costs associated with the loss, restoration and decontamination of critical data.

Connect with us to access cyber risk management expertise and guidance for protecting your business operations.

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Sources

¹Desktop Windows Version Market Share in Australia - November 2025, Statcounter Global Stats, accessed 08 Dec 2025.

²What Was the WannaCry Ransomware Attack?, Cloudflare, accessed 08 Dec 2025.

Disclaimer

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