Last Updated on 7 June 2023 by Alastair Digby
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When looking to improve your organization’s security posture, regular vulnerability scanning and penetration testing are two security activities you’re probably aware of. But the marketing of these services online is ripe to cause misunderstanding and confusion about what they involve and when you need them.
This article provides an in-depth guide comparing vulnerability assessment vs penetration testing, including what each process involves and how they differ. Using this knowledge, you’ll be better equipped to understand these different service offerings and know whether you need one or both to strengthen your organization’s security program.
Vulnerability Assessments and Penetration Testing Explained Briefly
A vulnerability assessment is a process that seeks to identify known security vulnerabilities in your applications, hardware, firewalls, and other IT systems. You then classify and prioritize identified vulnerabilities for remediation based on the severity of risk they bring to your business. Often, these vulnerabilities creep into an environment when IT teams fail to apply missing patches that address them.
Vulnerability assessments have been around for a long time, and they aren’t just restricted to the area of information security. Formerly dependent on manual analysis, the first automated vulnerability scanners emerged around the mid-1990s. A rather unimaginatively named Internet Scanner attracted media attention when PC Mag described how the tool could check for more than 100 vulnerabilities.
Internet Scanner was easier to use than the notorious SATAN tool, which the US Department of Justice temporarily had its sights on due to potential national security issues flagged by the tool. There are now hundreds of commercially available and open-source vulnerability scanning tools, such as Nmap, Metasploit, and Nessus.
A penetration is a simulated cyberattack in which a company enlists the help of ethical hackers to find and exploit weaknesses in their own IT environment in much the same way as a real-world threat actor would when conducting a planned cyberattack. This controlled, intentional attack on your environment could cover just a single area of your infrastructure, such as the external attack surface, or it could focus on a specific business department.
The history of penetration testing stretches back at least 50 years. In the early 1970s, the federal United States government began recruiting groups of hackers termed “tiger teams” to break into the primitive computer systems used in the military and in other areas of government. They were guided by computer security pioneer James P. Anderson’s series of steps for penetration tests, which included finding an exploitable vulnerability, building an attack around it, and then testing the attack. Modern pen tests are far more complex, but they still build from this basic foundation.
Vulnerability Scanning vs Penetration Testing: Key Differences
With these brief explanations in mind, now let’s move on to highlight some of the key differences between vulnerability scanning vs penetration testing.
The findings revealed during a vulnerability assessment are known vulnerabilities in your software, firmware, and operating systems that could potentially be exploited by a malicious threat actor. One way to view this is that a vulnerability assessment tries to go as wide as possible in finding vulnerabilities in systems. The heavy reliance of vulnerability assessments on scanning tools means false positives are sometimes included in findings.
Penetration tests discover and actively exploit weaknesses in your security defences that aren’t limited to known vulnerabilities. These weaknesses could include lax processes and misconfigurations. The approach here calls for ethical hackers to dig deep into the system or environment being tested and actively exploit weaknesses. False positives aren’t a concern in pen test reports because it lists weaknesses that the ethical hacker successfully exploited (or could’ve successfully exploited).
Degree of automation
While testers make use of several types of automated tools throughout the various stages of penetration testing, the process mostly rests on manual techniques. An example of something that a tester might turn to automation for is using an email scraper to find email addresses for company employees and attempt to target them with social engineering. Much of the process though sees testing teams constantly tweak and refine what they do in order to find a route into the system under scrutiny.
Vulnerability assessments feature a much greater degree of automation than penetration tests. The primary tool used to carry out an assessment is a vulnerability scanner, which runs automatically and rapidly. Not only is the scanning for vulnerabilities automated, but most modern tools also classify identified vulnerabilities for you so that you can easily prioritize what to fix.
The majority of businesses that run penetration tests only do so once or twice per year. Some companies might also run a pen test after significant changes to network infrastructure. While annual or semi-annual is the typical frequency of penetration testing, the prevailing wisdom is being challenged in light of emerging threats and constantly changing IT environments. There is now a push towards continuous penetration testing that leverages external attack surface monitoring (because this is the part of your environment under most threat) along with on-demand penetration testing.
Since vulnerability assessments are faster to run, companies typically opt for a frequency of at least quarterly or after any significant network change, such as switching your firewall vendor or allowing employee-owned IoT devices to connect to your network.
Skill level involved
Ethical hackers who carry out penetration tests require advanced knowledge across several domains, including programming, networking, and operating systems. There is a high level of skill involved in any thorough penetration test, and ethical hackers have often spent years honing their knowledge as security analysts, system admins, and programmers. People with the necessary skills are much sought-after, and it’s for this reason (among others) that companies often turn to third-party services for penetration testing.
Vulnerability assessments do not require a similar level of technical knowledge or skill as pen tests. It’s perfectly fine to assign responsibility for your vulnerability assessments to in-house security teams, although you’ll still need third-party help with some sort of vulnerability discovery tools.
Why You Need Both
A comprehensive security strategy should include both vulnerability assessments and penetration tests because they both provide value in their own ways. Vulnerability assessments provide a list of low-hanging fruit vulnerabilities that you can remediate with appropriate security patches before threat actors get to them. Pen tests deeply probe systems under scope (eg web apps, external network, internal network) for any weaknesses whether they are known software vulnerabilities or flaws in security controls and processes.
For regulatory compliance, PCI DSS actually mandates both vulnerability scans and penetration tests to protect cardholder data, which exemplifies the perceived value that both of these security activities can provide in strengthening your organization’s security posture.
At Informer, we recognize the pivotal role of both vulnerability assessments and penetration testing in today’s security landscape. Our attack surface management platform includes comprehensive vulnerability discovery, while our expert testing teams deliver pen test results in real-time into your SaaS platform so there’s no waiting around for reports.