What is patch management? A guide to staying secure and compliant

Defining patch management

Patch management is the disciplined process of keeping software and operating systems up to date by applying vendor-issued fixes. These fixes, or patches, address security vulnerabilities, improve stability, and ensure compliance with industry standards. Without them, known weaknesses remain open doors for attackers.

On an enterprise scale, patch management means more than turning on automatic updates. It requires visibility across thousands of endpoints, centralized policy enforcement, and careful control over which patches are applied, when, and how. That balance of speed and precision is what reduces risk without breaking business-critical workflows.

Patch management maturity: From basic updates to enterprise resilience

Not every organization approaches patching the same way. The level of maturity in patch management often depends on size, resources, and regulatory obligations. On one end of the spectrum are small teams relying on ad hoc updates. On the other are enterprises orchestrating patching across millions of endpoints with dedicated vulnerability management platforms. Most businesses fall somewhere in between.

Manual, ad hoc updates

At the least mature level, users or IT staff update software only when prompted or when problems arise. There is no central visibility, which means patches are easy to miss. This approach is common in very small or resource-constrained businesses, but it leaves major gaps that attackers can exploit.

Basic built-in auto-updates

A step up is relying on the update settings included in specific applications, such as Windows Update or Google Chrome’s built-in updater. This reduces the number of missed patches, but third-party applications and legacy software often remain out of date. Reporting and control over missing patches are minimal, which makes compliance a challenge.

Scripted or Group Policy-based updates

Some small and midsized businesses advance their maturity by using scripts or Group Policy Objects to enforce updates. This adds automation and consistency but requires ongoing maintenance and technical expertise. It tends to work best in Windows-centric environments but does not easily extend to diverse applications.

Endpoint management tools

The next maturity level is achieved through centralized endpoint management platforms such as RMM (Remote Monitoring & Management) or MDM (Mobile Device Management). These give IT administrators visibility, scheduling, and reporting across many devices. For SMBs, this step is often the most significant leap forward, because it replaces scattered, device-level patching with centralized accountability.

Dedicated patch management solutions

Organizations that need more precision turn to dedicated patch management tools. These cover both operating systems and third-party applications, allow policies to be tailored, and include risk-based prioritization and staged rollouts. IT teams gain confidence that nothing slips through the cracks.

Full vulnerability and risk-based patch management

At the most advanced stage, patching is integrated with vulnerability management. Tools such as Tenable or Qualys help prioritize patches not only by severity but also by exploitability and business risk. Orchestration ensures patches are deployed quickly, often automatically. This level of maturity is most common in large enterprises and government agencies, but SaaS delivery models are making it more accessible to smaller businesses.

Where SMBs fit in

For small and midsize businesses, maturity usually falls in the middle of this scale. They may have moved beyond built-in auto-updates but lack the staff and budget to operate full vulnerability management suites. This is the point where solutions like ThreatLocker Patch Management deliver the greatest value: enterprise-grade visibility and control, combined with automation that reduces manual effort, all without the complexity of heavyweight orchestration platforms.

When missed patches turn into trouble

The importance of disciplined patch management is not theoretical.  Travis v. Legacy Treatment Services, a class action complaint filed this month, alleged the healthcare provider ran outdated systems and missed timely patches, increasing the risk of ransomware that exposed sensitive patient data. The lawsuit highlights what happens when patch management is neglected: technical debt turns into legal liability.

For enterprises bound by frameworks like HIPAA, PCI DSS, or GDPR, this risk is magnified. Regulators expect reasonable safeguards against known threats, and failing to patch is one of the most visible ways to fall short.

Breaches resulting from missed patches

Attackers don’t always need brand-new exploits to break into systems. Many breaches are carried out with vulnerabilities that already have vendor patches available but haven’t yet been applied. Sophisticated threat actors to even lower-level cybercriminals can actively track patch releases, then race to weaponize the known weaknesses.

A common tactic to avoid detection is to wait just long enough—days or a week—while enterprises struggle through their patch testing, then launch attacks while the window is still open. By the time the patch is fully deployed, the attacker may already have established persistence in the environment.

This is why timeliness is as important as accuracy in patch management. Delays meant to reduce operational risk can end up amplifying security risk if they stretch too long.

High-profile breaches caused by a failure in patch management have affected major companies like Equifax, Marriott, and SolarWinds, as well as the global impact of the WannaCry ransomware. These incidents demonstrate that neglecting software updates for known vulnerabilities can lead to massive data theft and operational disruption.  

Equifax (2017)

One of the most well-known examples of a data breach resulting from poor patch management is the 2017 Equifax incident.  

• Vulnerability: Attackers exploited a known flaw in the Apache Struts web application framework (CVE-2017-5638) to gain unauthorized access. A patch for this critical vulnerability had been publicly available for over two months.
• Breach details: By not applying the patch, hackers were able to access and steal the personal information of 147 million people, including Social Security numbers, birth dates, and credit card numbers.
• Consequences: The breach cost Equifax millions in settlements and legal fees, led to major reputational damage, and resulted in executive resignations.  

WannaCry ransomware attack (2017)

The WannaCry attack infected hundreds of thousands of computers in over 150 countries, encrypting files and demanding a ransom.  

• Vulnerability: The malware exploited the "EternalBlue" vulnerability in Microsoft Windows, a flaw for which a security patch (MS17-010) had been released two months earlier.
• Affected systems: The patch was not applied by many organizations, including significant parts of the UK's National Health Service (NHS), which was one of the most impacted victims.
• Consequences: The attack caused major disruption to hospitals, businesses, and government agencies. While a "kill switch" was found to slow the spread, it served as a wake-up call for the importance of timely patch management.  

Marriott/Starwood (2018)

In 2018, Marriott disclosed a breach impacting up to 339 million guest records traced back to vulnerabilities in the Starwood hotel network it had acquired in 2016.  

• Vulnerability: A threat actor exploited a vulnerability in an outdated and unsupported Starwood system to gain access. The attackers maintained a presence in the network for four years, starting in 2014, before being detected.
• Breach details: The hackers were able to steal administrative credentials and move through the network to install malware, siphoning massive amounts of customer data.
• Consequences: The breach resulted in multimillion dollar regulatory fines from the FTC and UK regulators for failing to implement reasonable security, including proper patching

The importance of testing before deployment

While speed is critical in patching, so is caution. Even legitimate vendor patches can sometimes introduce unexpected issues that disrupt business operations. For this reason, every organization should have at least a basic testing process in place before rolling out patches to production systems.

In mature IT environments, this often means maintaining a dedicated testing environment that mirrors critical infrastructure. But even for SMBs without the resources for a full sandbox, a single non-production machine can serve as a vital safeguard. By applying patches there first, IT teams can quickly identify compatibility problems before they affect end users. Patch testing also reveals how a software update behaves, informing an organization about how it might want to structure its patch rollout procedure. Observing how long a patch takes to install, or if it adversely affects business-critical processes, can help operations teams decide how to schedule a patch maintenance window that best fits business rhythms.

Testing doesn’t have to mean delaying security indefinitely. The goal is to strike a balance: validate that the patch won’t break workflows, then deploy it as quickly as possible across the environment. A short testing cycle reduces risk while still closing vulnerabilities in a timely manner.  

This practice is particularly important for organizations subject to compliance frameworks. Regulators expect reasonable safeguards and demonstrating that patches are tested before deployment shows due diligence in protecting both security and business continuity.

ThreatLocker Patch Management

ThreatLocker Patch Management is built to deliver that balance. Acting as a vigilant guard, it continuously scans your environment for outdated applications—even portable apps—and flags those that need patching. Instead of IT teams chasing alerts across multiple vendor sites, all patch data is consolidated into one centralized console.

From there, administrators can:

• Automate patch deployment across operating systems and third-party applications.
• Define granular policies for which patches to install, defer, or block.
• Demonstrate compliance with auditable reports showing patch status across the enterprise.

ThreatLocker Patch Management patches supported applications automatically. Applications that require a restart for a patch to apply will be automatically updated the next time the application is restarted

By removing manual overhead and enforcing consistent policies, ThreatLocker helps enterprises close vulnerabilities faster while keeping full control over the process.  

Security and compliance benefits

Centralized patch management does more than strengthen security hygiene. It helps organizations prove compliance to auditors, satisfy regulatory timelines for patching critical vulnerabilities, and protect customer trust. HIPAA requires covered entities to defend against known risks. PCI DSS demands critical patches within 30 days of release. ThreatLocker Patch Management gives security teams the visibility, automation, and reporting to meet those obligations.

Building resilience with Zero Trust

Patch management is not an isolated task. It is a pillar of a Zero Trust strategy. Even with Allowlisting, Ringfencing®, and Storage Control in place, unpatched vulnerabilities remain attractive to attackers. Closing them quickly reduces the blast radius of compromise and strengthens enterprise resilience.

The takeaway is clear: patching is not optional maintenance. It is one of the most direct ways to stop breaches before they happen and avoid the financial and reputational costs of non-compliance. With ThreatLocker Patch Management, enterprises gain the control and automation needed to turn patching from a reactive chore into a proactive defense.

See ThreatLocker in action. Schedule your customized demo today.

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