Zero-day vulnerabilities are the cyber security equivalent of a trapdoor. You don’t know it exists until it has already been triggered. By then, attackers are inside your network.
These flaws exist in software or systems before the developer is aware of them. Once discovered and exploited, they become known as zero-day attacks. Threat actors often move quickly to exploit the window between vulnerability discovery and patch release, especially when the vulnerability affects critical systems such as browsers, cloud platforms, or identity services. During the period when a vulnerability remains a vulnerability secret, it may be traded on the black market for significant sums before it becomes public knowledge, increasing the risk to organisations.
Here’s how to understand the risk, and what to put in place to reduce your exposure.
What makes zero-days so dangerous
Zero-days are exploited before anyone has time to patch or defend against them. These attacks are often:
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Difficult to detect using signature-based tools
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Targeted at high-value assets
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Used to establish initial access in sophisticated attack chains
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Linked to ransomware, cybercrime, and state-sponsored activity
Attackers frequently use zero-day exploits to deliver malicious code or zero-day malware, which can bypass traditional defenses and establish a foothold in targeted environments.
As the threat landscape evolves, attackers are leveraging automation, AI, and supply chain weaknesses to expedite exploitation.
Not every vulnerability is disclosed for the right reasons
Attackers benefit from keeping vulnerabilities hidden for as long as possible. The longer a flaw remains unknown, the longer they can exploit it.
This is why responsible disclosure is essential. Security researchers play a crucial role as they identify vulnerabilities and report them to software developers, who then create and release patches to protect users.
The Missing Link’s Offensive Security team regularly discovers and reports vulnerabilities through recognised global channels. We are also a CVE Numbering Authority, one of the few in Australia, which allows us to publish vulnerabilities in the global CVE system formally.
This helps ensure issues are addressed before they are exploited in the wild.
Antivirus alone won't stop a zero-day
Traditional antivirus relies on signatures of known threats. A zero-day has no signature. This makes it invisible to most legacy tools.
While some antivirus platforms use heuristics or basic behavioural analytics, they often lack the depth to detect and stop modern attacks early. Effective threat detection requires advanced methods for detecting suspicious activity that may indicate a zero-day attack.
What you actually need: NGAV, EDR, and expert monitoring
Modern endpoint protection focuses on behaviour and context, not just known patterns.
Look for a solution that includes:
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Next Generation Antivirus (NGAV)
Blocks threats using machine learning and real-time behaviour analysis -
Endpoint Detection and Response (EDR)
Monitors all endpoint activity and helps you investigate and respond quickly -
Extended Detection and Response (XDR)
Connects data across endpoints, cloud, identity and network to uncover advanced threats -
Managed Detection and Response (MDR)
A 24/7 expert team that actively monitors, investigates and acts on threats
These solutions are designed to address new threats, monitor for unauthorised network access, and help organisations configure strong security settings to reduce risk.
The Missing Link provides these services through our Global Security Operations Centre, powered by local analysts and backed by industry-leading tools.
Case in point: Security that drives action
Using NGAV allows for time and money savings and can be a great teaching tool for staff. For example, David Lucas, Customer Solutions Manager, George Weston Foods says:
“The new platform is continually kept up to date with categorisation and profiling of new threats and classification of existing traffic. Being able to focus on what is actually happening rather than reacting to close a new threat has saved a lot of time. Being able to see where our compliance was not 100%, we were able to act early and educate our people on the dangers and implications of not following our policies. This has helped us pro-actively understand patterns and educate our staff about the risks of the internet, before we have a serious incident.”
How to reduce your exposure to zero-day attacks
If you want to reduce risk, start with these five actions:
Many organisations remain at risk due to outdated software and unpatched known vulnerabilities in their computer
systems.
1. Run regular security assessments.png?width=549&height=549&name=reduce%20zero-day%20(1).png)
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Penetration testing
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Vulnerability assessments (including identification of software vulnerability)
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Cloud and application security reviews
2. Harden your environment
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Apply the principle of least privilege
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Remove unnecessary admin rights
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Enable application control and whitelisting
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Regular software updates are essential to reduce risk from known vulnerabilities and outdated software.
3. Deploy the right tools
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NGAV for behaviour-based malware protection
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EDR or XDR for visibility and detection
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SIEM or MDR for 24/7 monitoring and expert response
4. Follow proven frameworks
Implement the ASD Essential Eight as a baseline. When correctly implemented, these eight controls can mitigate over 85 per cent of common attacks.
5. Educate your workforce
People remain the most common entry point for attackers. Phishing simulations and security awareness training can dramatically reduce the risk of user error. Attackers often seek to steal data by exploiting human error.
So how do I protect my business?
The Missing Link helps businesses of all sizes reduce their exposure to zero-day threats. Our cyber specialists:
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Identify gaps through detailed assessments
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Simulate real-world attack paths to uncover unknown risks
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Deploy and manage endpoint and cloud security technologies
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Deliver ongoing support and monitoring via our Australian-based GSOC
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Align your environment with industry frameworks like ISO27001, NIST, SOCI and ASD 8
Ongoing monitoring and support help ensure that zero-day vulnerability risks are detected early and that vulnerabilities are not left unaddressed for an extended period.
Start with an assessment
Most businesses don’t realise their biggest security gaps until they are exploited. We help you find and fix them before attackers do.
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