Virtual patching is a security mechanism used to protect systems and applications from known vulnerabilities. This is done by implementing temporary security controls without modifying the underlying code.
It allows organizations to address security issues promptly, particularly when traditional patching is not possible due to system downtime, application complexity, or resource constraints. Virtual patching offers an immediate way to shield vulnerable systems while waiting for the official patch or fix.
Virtual Patching Defined
Virtual patching means applying a layer of protection that mimics the effect of a standard patch by intercepting and blocking cyberattacks that target a specific vulnerability in your environment.
Unlike a standard patch, which fixes the flaw in the software code itself, virtual patching uses network-based controls, such as firewalls and intrusion prevention systems (IPS), to block exploit attempts in real time. Its goal is to prevent attackers from exploiting vulnerabilities until your organization applies a permanent solution, such as a code update.
Virtual patching is invaluable when dealing with zero-day vulnerabilities, a case where a fix is not immediately available. It also has a perfect application for legacy software and outdated systems that are either difficult to update due to compatibility issues and technical constraints or lack standard patches and updates altogether.
How Does Virtual Patching Work?
Virtual patching works as an interim defense mechanism that prevents threat actors from reaching the vulnerable software. Here’s how it typically works:
- Vulnerability Identification: The first step is vulnerability discovery, usually through security scans, threat intelligence feeds, or monitoring alerts. Once you discover a vulnerability, your team evaluates it for its potential operational or business impact and the likelihood of attackers exploiting it.
- Creation of a Virtual Patch: A virtual patch is put in place based on the vulnerability in question. An example of this type of action is configuring network security controls (for instance, firewalls or IPS systems) to filter or block traffic that attempts to exploit the vulnerability.
- Implementation of the Virtual Patch: Your security or IT operations/network team then deploys the virtual patch at the network perimeter or directly on the affected systems. It’s worth noting that, unlike standard patches, virtual patches do not entail changes to the underlying code of the vulnerable system, software, or application.
- Monitoring and Review: Applying the virtual patch is not where the process ends. You must keep monitoring your environment for new vulnerability exploitation attempts. The effectiveness of the virtual patch should be continuously reviewed, especially as new attack techniques or updates to the vulnerability become available.
Virtual Patching vs. Other Security Measures
Virtual patching can work as the only practicable way of addressing threat exposure, as a cybersecurity measure complementary to more traditional measures, or as an integral part of larger cybersecurity programs:
- Virtual Patching vs. Standard Patching: Standard patching means you’re changing the code to fix a vulnerability. It’s a permanent fix that removes the root cause of a security problem. In contrast, virtual patching doesn’t entail code changes. It means you’re blocking exploit attempts at the network level, and as such, it’s considered a temporary solution until a permanent fix is applied. However, unlike standard patching, it provides immediate or at least a much faster protection.
- Virtual Patching vs. IDS (Intrusion Detection Systems ): An IDS monitors network traffic, looking for suspicious activity, but doesn’t actively block or prevent attacks. That is markedly different from virtual patching, whose entire point is to prevent or block ongoing cyberattacks. Clearly, out of the two, virtual patching is the more proactive defense.
- Virtual Patching vs. Vulnerability Management: Vulnerability management typically revolves around standard patching. However, virtual patching can function as a mitigation measure within a larger vulnerability management program, applied when standard patching takes too long or is impracticable (e.g., in legacy software or enterprise environments with thousands and thousands of vulnerabilities).
Examples of Virtual Patching in Use
Virtual patching is becoming increasingly common in enterprise environments and industries with legacy systems, mission-critical applications, or strict uptime requirements. More precisely, you can expect to find it in:
- ICS/OT environments, where you can’t easily reboot or update devices
- Healthcare, where medical devices might not be patchable due to FDA or vendor constraints
- Finance, where downtime can be extremely costly or where legacy infrastructure still exists
Two examples of a practical application of the concept of virtual patching are the following:
- WAF (web application firewall): If you discover a vulnerability in a web application, you don’t have to alter the underlying code. Instead, you can configure a WAF to block malicious requests that try to exploit the vulnerability.
- Workload patchless mitigation: This security solution creates a real-time, active defense layer around an application’s execution. It doesn’t fix the underlying flaw in the code, but it makes it unexploitable by preventing malicious attackers’ actions. It provides immediate, often “zero-dwell time” protection, functioning as a shield between the adversary and your application.
Virtual Patching: The Lifeline for Risky Times
Virtual patching is a crucial defense mechanism that blocks known exploit attempts and mitigates security risks. It is especially helpful when a standard patch is:
- Delayed because of complex and long patching cycles.
- Unfeasible due to system constraints or the sheer number of exposures in your environment.
- Unavailable because of the dated nature of your software or the lack of support.
In short, virtual patching has become a critical security measure to build a more resilient posture during high-risk periods and while waiting for an official patch.