How can you be sure you're actually secure? The role of Penetration Testing and Security Audits

30 Apr 2026, by Micron21

Last month we touched on the Essential Eight, which are the prioritised mitigation strategies and guidance provided by the Australian Signals Directorate (ASD) to help Australian organisations protect their internet-connected IT networks.  Implementing these eight controls - patching applications, patching operating systems, multi-factor authentication, and so forth - goes a long way to hardening your environment against the most common cyberattacks.  However, even after going through the considerable time and effort of putting all of these protections in place, there's still one important question left unanswered: How do you actually know that you're secure?

The uncomfortable truth is that you don't really know for sure  - not until a genuine attempt to break in has happened by someone with the skills, the time, and the motivation to break in.  Without that, it's quite possible that there are glaring holes in your security posture that you’d be completely unaware of.   As examples, a misconfigured service, a forgotten test account, an unpatched library nested deep within a dependency tree, or a business logic flaw that no automated scanner could ever hope to find.  Any one of these can be enough to give an attacker the foothold they need to get in.

For these reasons and for those organisations that are able to foot the bill, “Penetration Testing” has become a key tool in ensuring that you are as secure as you believe you are.  In this month's blog, we'll be exploring what penetration testing actually is, what it's useful for, and when you should consider it for your business.  We'll also be talking about security reviews more generally, what's involved, and a few other things that you should be aware of before going down this path.

What is Penetration Testing?

To understand what penetration testing is, it helps to first understand the broader world of "hacking" - a term that gets thrown around quite loosely in the media, but which actually covers a wide spectrum of activity.  Within the cybersecurity industry, hackers are often categorised based on their intent and whether or not they have permission to do what they're doing.  The three commonly used categories for this are "Black Hat", "Grey Hat", and "White Hat".

Black Hat hackers are those who break into systems with malicious intent and without permission. This is the category most people picture when they hear the word "hacker" - it includes everything from cybercriminals stealing credit card details, right through to state-sponsored actors conducting espionage.

Grey Hat hackers sit somewhere in the middle. They typically don't have malicious intent, however they also don't have permission to be probing or breaking into the systems they target. A common example would be a researcher who finds a vulnerability in a company's website without being asked to look, then disclosing the issue to the company afterwards.  Whilst usually well-intentioned, this activity is still illegal in most jurisdictions, including Australia.

White Hat hackers are the cybersecurity professionals who do the same kinds of work as their Black Hat counterparts - probing, exploiting, and breaking into systems - but with explicit permission from the system's owner and with the goal of improving security, rather than exploiting it.

Penetration testing sits firmly in the White Hat camp.  At its core, it's the act of paying cybersecurity professionals to apply their tradecraft - allowing them to incorporate the collection of tactics, techniques, procedures, and tools that could be used by potential attackers to compromise you when attempting to break into your systems and organisation. The key difference here is that you've given them full permission to do so, within an agreed scope.

A typical penetration test will usually start with a scoping phase, where you and the testing team agree on what is in-scope and what is out-of-scope.  This is important, as it ensures that critical production systems aren't accidentally taken offline, and also that the testers focus their effort on the areas that matter most to your business.  From there, the actual engagement usually moves through several stages, including: Reconnaissance - the gathering of information about the target;  Enumeration - identifying services, accounts, and entry points;  Exploitation - actually attempting to break in; and  Post-exploitation - seeing what an attacker could do once they're inside, such as moving laterally to other systems or escalating privileges.

The tools used during these engagements vary widely, and often include a mix of well-known security tooling - such as Burp Suite for testing web applications, Nmap for network reconnaissance, Metasploit for exploitation, and BloodHound for mapping Active Directory environments - along with custom-built scripts and entirely manual techniques.  A good penetration tester won't simply run a tool and hand you the output. Instead, they'll use these tools as a starting point and rely on their own knowledge and creativity to chain findings together in ways that mirror what a real attacker would do.

Once the testing is complete, the findings are written up in a report.  A well-written penetration testing report typically includes an executive summary aimed at non-technical stakeholders, a detailed breakdown of each finding (including how it was discovered, how serious it is, and how it can be reproduced), as well as concrete recommendations on how to remediate each one.  Most reputable testing providers will also offer a remediation re-test once you've addressed the findings, where they verify that your fixes actually hold up.  Our partners take exactly this approach - documenting everything they find along with how they'd approach fixing it, sharing it as a draft before finalising, and verifying the fix once it has been resolved.

In terms of cost, penetration testing in Australia varies significantly based on the scope of the engagement. As a rough guide:

• A small, focused engagement - such as testing a single web application of moderate complexity - will typically range from around $6,000 to $20,000 AUD.
• A medium-sized engagement covering an external network perimeter, a couple of web applications, and a basic internal network test will usually range from $15,000 to $35,000 AUD.
• Larger engagements - such as full red-team exercises, comprehensive cloud environment reviews, or testing across multiple applications and infrastructure - can easily reach $25,000 to $50,000 AUD or more.

These figures are indicative only, and the actual cost will depend on factors such as the complexity of the systems being tested, the duration of the engagement, the seniority of the testers involved, and whether re-testing is included.  As a general rule, the more context you can provide upfront and the better-defined your scope, the more value you'll extract from the engagement.

The differences between Penetration Testing and Vulnerability Scanning

Another service that we offer, which is often confused with penetration testing (due to the similar terminology)  is “Vulnerability Scanning”.  Whilst the two are often spoken about interchangeably, they're quite different services. Both are important techniques that you should consider utilising as part of a layered approach to your security.

The simplest way to think about the difference is this: vulnerability scanning is an automated process, whereas penetration testing is an active and manual process performed by trained cybersecurity professionals (even though those professionals often use automated tools as part of their work).

A vulnerability scanner will systematically probe your systems, looking at what services are open and accessible, and then comparing what it finds against a database of known vulnerabilities.  If it finds a service running an outdated version that's known to be vulnerable, it will flag it.  These scans can be scheduled to run regularly – daily, weekly, or monthly - which means they're particularly good at catching changes over time.  A system that wasn't vulnerable last week may suddenly be vulnerable this week due to a new exploit being published, or due to a configuration change made by an administrator.  A scheduled vulnerability scan will catch this and alert you, often well before an attacker has a chance to take advantage of it.

Penetration testing, on the other hand, is something that's typically done at a single point in time and goes far beyond what an automated tool can detect.  A skilled tester will look at how your systems are configured in the context of your business, identify logic flaws that no scanner would ever spot, chain multiple low-severity findings together to achieve high-severity outcomes, and approach your systems with the same creativity that a real attacker would.  This is something that automated tools - even very sophisticated ones - simply cannot do.

This distinction is becoming even more important in light of AI.  Penetration testers are increasingly able to leverage AI tools as a force multiplier - using them to rapidly probe systems, generate variations of attacks, write custom exploit code, and analyse large volumes of output.  Whilst this means that the bar for what testers can accomplish in a given engagement is rising, it also unfortunately means that attackers are gaining the same advantages.  This makes regular testing more important than ever.

In terms of when to use each:

• Vulnerability scanning is best run continuously or on a regular schedule.  It's relatively low-cost, can cover a wide range of systems. It is excellent at catching the slow drift of vulnerabilities being introduced into your environment over time.
• Penetration testing is best done periodically - often annually, or whenever significant changes are made to your environment. This is the right tool to use when you want to genuinely understand how your systems would hold up against a determined attacker.

The two complement each other well.  Vulnerability scanning casts a wide and shallow net continuously, whilst penetration testing goes deep at a single point in time.  Used together, you get both the breadth and depth needed to catch the issues that matter.

How Security Audits fit in with improving your cybersecurity posture

In much the same way that vulnerability scanning and penetration testing complement each other, “Security Audits” also play an important role when used in conjunction with the other two.  In most engagements, security audits are usually performed at the beginning - prior to any more in-depth penetration testing – in order to give you an overall view of the cybersecurity posture and state of your systems, as well as your organisation more generally.

What sets a security audit apart is that it doesn't just focus on the technical side of your cybersecurity.  It also looks at your company culture, your ongoing practices, the attitudes of your staff, and your overall approach to security as an organisation.  The reasoning behind this is simple - even the most technically secure environment can be undermined by a single staff member who clicks the wrong link in a phishing email, or by a policy that allows credentials to be shared between team members.

A security audit will typically look for things that are lacking, things that can be improved, and recommendations across multiple areas - including staff training programs, changes to internal policy, improvements to onboarding and offboarding procedures, and conversations with staff about the importance of maintaining a proper cybersecurity posture. I t's just as much about people and processes as it is about technology.

That being said, audits absolutely also do analyse things from a technical perspective.  This includes looking at the security appliances and services that should be added to your environment; analysing whether the appliances and services that you currently have are configured correctly; and identifying any technical weaknesses that could leave you open to attack.  Frameworks such as the Essential Eight, ISO 27001, and NIST are often used as the benchmark against which environments are assessed, depending on what's most relevant to your industry and regulatory obligations.

The output of a security audit is usually a prioritised list of recommendations - often grouped by impact and effort - that your organisation can then work through over time.  This becomes the roadmap that informs everything else, from which technical controls to implement first, to which areas warrant a deeper dive via penetration testing later down the track.

Bringing it all together

Cybersecurity isn't a destination, but rather an ongoing process.  Implementing the Essential Eight or any other framework is an excellent starting point, and goes a long way to protecting you from the most common forms of attack.  However, the only way to truly know whether your defences hold up…. is to test them.

Penetration testing gives you that confidence, by paying skilled professionals to genuinely attempt to break into your systems, and then reporting back on exactly what they found and how to fix it.  Vulnerability scanning complements this by continuously monitoring your environment for new weaknesses as they emerge, ensuring that drift over time doesn't catch you unaware.  And security audits tie it all together by stepping back and looking at the broader picture - both technical and cultural - to identify the gaps in your overall security posture and provide a roadmap for improvement.

For organisations that are serious about their cybersecurity, all three of these services have a role to play, and they're most effective when used in conjunction rather than in isolation.  The exact mix that's right for your organisation will depend on your size, your industry, your regulatory obligations, and the value of the data you're protecting.  However, even smaller organisations can benefit from at least starting with a security audit, scheduling regular vulnerability scans, and then graduating to penetration testing once the most obvious gaps have been closed.

Have any questions about Penetration Testing, Vulnerability Scanning or Security Audits?

If you have any questions about Penetration Testing, Vulnerability Scanning, or Security Audits - or if you'd just like to generally chat about where to start in improving your overall cybersecurity posture - let us know!

We're able to help you with everything from a once-off penetration test of a single application, right through to a comprehensive security audit of your entire organisation, as well as assisting with implementing the recommendations that come out of those engagements.

You can call us on 1300 769 972 (Option #1) or reach us via email at sales@micron21.com.

Sources

1, Australian Signals Directorate, "Essential Eight Maturity Model", <https://www.cyber.gov.au/business-government/asds-cyber-security-frameworks/essential-eight/essential-eight-maturity-model>

2, Micron21, "Penetration Testing & Security Audits", <https://www.micron21.com/enterprise/penetration-testing-and-security-audits>