The introduction of a new version typically implies an evolution, marked by improvements and the incorporation of novel features. In the specific context of the CVSS (Common Vulnerability Scoring System) calculator, it becomes pertinent to scrutinize the extensive alterations made to its specifications. Embarking on a research and analysis journey becomes imperative to determine the impact and efficacy of the revamped CVSS calculator.

CVSS v4 Calculator © 2023 FIRST.ORG
CVSS v4 Calculator © 2023 FIRST.ORG

The predominant transformation lies in the restructuring of metric categories, with a noteworthy modification being the rechristening of the ‘Temporal Metric Group’ to the more encompassing ‘Threat Metric Group’. This alteration signifies a shift in focus from temporal aspects alone to a broader consideration of potential threats, suggesting a more comprehensive evaluation framework.

Furthermore, a significant augmentation comes in the form of the introduction of the ‘Supplemental Metric’ group. This addition suggests a recognition of the need for supplementary measures that can contribute to a more nuanced understanding of the metrics landscape. The inclusion of this new group implies an acknowledgment of diverse factors that might impact the assessment, thereby enriching the overall analytical framework.

Beyond the overarching alterations in metric groups, it’s imperative to delve into the nuanced modifications within the existing groups. These alterations may encompass revisions in the definition of specific metrics, adjustments in the weighting assigned to different parameters, or the inclusion/exclusion of certain elements. These internal changes are pivotal as they can significantly influence the overall effectiveness and relevance of the metrics framework.


Change in metric groups

CVSS v4 is composed of four metric groups.
CVSS v4 is composed of four metric groups.

In the evolution of the ‘Base metric group’, a notable transformation has occurred with the introduction of three pivotal elements: ‘Subsequent System Confidentiality’, ‘Subsequent System Integrity’, and ‘Subsequent System Availability’. Simultaneously, the once-inclusive ‘Scope’ element has been excised. This alteration can be succinctly encapsulated in a single word — ‘Interesting’.

Delving into the intricacies of this metamorphosis reveals a strategic response to the complexities inherent in contemporary architectural practices. In the realm of modern architecture, solutions are crafted as intricate amalgamations of multiple systems, each meticulously designed for a specific task. This paradigm not only champions the cardinal virtue of scalability but also begets a nuanced interdependency among these specialized systems.

The introduction of ‘Subsequent System Confidentiality’, ‘Subsequent System Integrity’, and ‘Subsequent System Availability’ is a discerning move reflective of this architectural ethos. By incorporating these elements, the vulnerability metrics now extend beyond the immediate system in question, reaching into the intricate web of dependent systems. This expansion underscores the holistic nature of system vulnerabilities, emphasizing their potential reverberations across the interconnected landscape of contemporary solutions.

In essence, this shift in the ‘Base metric group’ encapsulates the evolving paradigm of cybersecurity, where the assessment of vulnerabilities extends beyond individual components to encompass the intricate dance of interdependent systems. It exemplifies a forward-thinking approach that acknowledges the intricacies of modern architecture and aims to provide a more accurate and comprehensive evaluation of the security landscape. The term ‘Interesting’ succinctly captures the intrigue and significance of this nuanced and forward-looking adjustment.


How does the CVSS Calculator work?

When the CVSS vector for a particular vulnerability is input into the version 4 of the calculator, it yields a slightly lower score. It’s important to note that this discrepancy in scores is not a cause for concern, as the introduction of version 4 entails adjustments to the weighting of each element that contributes to the overall score.

But things are a bit different when the subsequent system elements are added to the equation because with this vulnerability you can bypass the authentication. In other words, you can become a system administrator in the application and therefore, you can change everything within the application.

Availability is definitely affected and depends on the creativity of the attacker, one could argue Confidentiality and Integrity are also affected. When only the element ‘Subsequent System Availability’ is changed to high, the score jumps to 9.9. It will be a solid 10.0 if you take the other 2 elements into consideration.

By incorporating the appropriate architectural principles, it is imperative to ensure that this interface does not coexist within the same network VLAN as the regular user environment. Addressing this concern falls under the purview of ‘Environmental — Exploitability metrics’, with a specific focus on the ‘Modified Attack Vector’ element. To mitigate the risk, one can transition the attack vector designation from ‘Network’ to ‘Adjacent’, thereby resulting in a reduction of the CVSS score.

If the impact of any subsequent system significantly jeopardizes safety in any aspect, it is imperative to modify the parameters of both ‘Subsequent System Impact — Integrity’ and/or ‘Subsequent System Impact — Availability’ to encompass the overarching concern of ‘Safety’. This adjustment will consequently lead to the subsequent update of the CVSS-Score.

A crucial factor to take into account is the progress in developing an exploit for the identified vulnerability. It’s important to note that not every reported vulnerability results in the creation of an exploit. The metric ‘Exploit maturity’ within the ‘Threat Metric’ group serves as a key indicator. Updating this metric to accurately represent the current status enables a corresponding adjustment in the overall CVSS score. It’s essential to exercise caution, as the calculator defaults to assuming the worst-case scenario. Only values such as ‘POC’ and ‘Unreported’ have the potential to modify the CVSS score.


Who is responsible for which element?

In the intricate landscape of vulnerability management, augmenting the CVSS-vector with comprehensive information is crucial for accurately determining the CVSS-Score. A pertinent question arises: who bears the responsibility for incorporating this vital information into the CVSS-vector? This responsibility, excluding the ‘Base’ and ‘Supplemental’ metric groups, squarely falls upon the shoulders of the Enterprise Vulnerability Management team.

However, navigating this terrain is not without its challenges. One notable hurdle is the limited support for this feature in many existing Vulnerability Scanning solutions. Even if a sophisticated solution is in place, capable of integrating this information into the CVSS-vector, another hurdle emerges: the origin of this data.

Unraveling the complexities further, obtaining information for metrics such as ‘Exploit Maturity’ poses a multifaceted challenge. The straightforward approach involves engaging the Cyber Threat Intelligence team at regular intervals, tasking them with assessing the status of exploit availability and maturity for all identified vulnerabilities within the organizational environment. On the surface, posing this question may seem straightforward, but delving into the intricacies of answering it reveals a labyrinth of complexities.

The intricacy lies not only in the diligence required to regularly consult the Cyber Threat Intelligence team but also in the nuanced interpretation of the obtained information. Assessing exploit availability and maturity demands a keen understanding of the threat landscape, the evolving nature of exploits, and a proactive stance in staying abreast of emerging cyber threats. Consequently, while the metric ‘Exploit Maturity’ may appear to be a relatively straightforward element within the CVSS-vector, the process of acquiring and interpreting the relevant data is far from facile. It demands a synchronized effort between the Vulnerability Management and Cyber Threat Intelligence teams, emphasizing the need for a holistic and proactive approach in fortifying the organization against potential cyber threats.

Unique number of vulnerabilities reported by year © cvedetails.com
Unique number of vulnerabilities reported by year © cvedetails.com

Data science to the rescue

In the rapidly evolving landscape of technology, one cannot escape the looming challenge of managing an overwhelming influx of data. The graph presented above starkly illustrates the escalating trend in reported vulnerabilities, a trend that paints a picture of a data avalanche, one that transcends mere numbers, surpassing 160,000 in the last decade alone.

Yet, the complexity of this scenario goes beyond the sheer volume of reported vulnerabilities. A pivotal aspect lies in navigating the intricate metrics encompassed within the ‘Environmental’ metric group. Delving into the realm of safety, for instance, demands an intricate understanding of which assets are responsible for managing safety. This raises the crucial question: Is this information meticulously cataloged in the CMDB?

Furthermore, consideration must be given to the existing security controls. Integrating this vital information into the CVSS vector becomes a challenging endeavor. This challenge propels us into the intricate world of data science, where the development of a tailored model becomes imperative for your unique environment.

The task at hand involves constructing a model adept at determining a CVSS-Score that accounts for ‘intra-zone exploitability’ (pertaining to exploits between various network zones), ‘interzone exploitability’ (focused on exploits within the same network zone), and ‘local exploitability’ (concentrating on exploits targeting the same asset). In this intricate model, the dynamic landscape of various active security controls must be considered.

Essentially, this journey into the realm of data science necessitates not only an understanding of the numerical trends in reported vulnerabilities but also a nuanced comprehension of the intricacies of one’s environment. It calls for the creation of a bespoke model that not only captures the quantitative aspects but also incorporates the qualitative nuances of security controls, ensuring a comprehensive and contextually relevant assessment of vulnerabilities. In this landscape, where technology and data intersect, the ability to navigate and harness this deluge of information becomes a strategic imperative for safeguarding the integrity and security of your digital ecosystem.

Consider a scenario where a vulnerability is identified within a system. If the vulnerability can only be exploited from within the same network zone, the CVSS-Score for ‘intra-zone exploitability’ is assigned a value of 0.

However, when assessing ‘interzone exploitability’, the CVSS-Score becomes intricately linked to the organization’s network security configuration. For instance, if access to the vulnerable interface is restricted and can only be achieved through a designated stepping stone, the CVSS-Score is subject to modification. This demonstrates that even a single security control, such as a Firewall Access Control List, plays a pivotal role in influencing the exploitability score.

The complexity of this scoring model increases exponentially when considering the integration of other security controls like Intrusion Prevention Systems, Web Application Firewalls, Endpoint Detection and Response, Antivirus, and more. Each of these controls contributes unique layers of protection, and their effectiveness in mitigating the vulnerability must be factored into the overall scoring model.

Developing a comprehensive and accurate model is essential for aiding the asset owner in prioritizing patch management. The more nuanced and thorough the model, the better equipped organizations are to make informed decisions about which vulnerabilities pose the greatest risk and, consequently, require immediate attention. This holistic approach ensures a more effective and targeted patching strategy, enhancing overall cybersecurity posture.


Conclusion

The exploration of CVSS v4.0 prompts a nuanced consideration of its impact on the crucial task of determining patch priorities within the realm of cybersecurity. Undoubtedly, the updated standard represents a significant stride forward in refining the accuracy and granularity of vulnerability assessments. It introduces enhanced metrics and a more comprehensive framework for evaluating the severity of security vulnerabilities, providing a more nuanced understanding of potential risks.

However, this advancement does not come without its challenges. One notable consequence is the increased complexity inherent in the updated standard. While the additional dimensions and factors contribute to a more detailed vulnerability assessment, they also introduce a level of intricacy that demands a deeper understanding and more sophisticated approach to implementation.

Furthermore, the effectiveness of CVSS v4.0 is contingent on the capabilities of the vulnerability scanning solutions employed in practice. Regrettably, the current landscape of such solutions often falls short in simplifying the complexities introduced by the updated standard. In some cases, these tools may not fully leverage the new metrics or may struggle to provide clear and actionable insights from the expanded set of parameters.

The synergy between CVSS v4.0 and existing vulnerability scanning solutions becomes a critical focal point. Bridging this gap requires not only advancements in scanning technologies but also an ongoing commitment to training and education for cybersecurity professionals. Organizations must invest in cultivating expertise that can navigate the intricacies of the updated standard and derive meaningful conclusions from the wealth of information it provides.

In conclusion, while CVSS v4.0 undeniably represents progress in the realm of vulnerability assessment, its success hinges on the ability of organizations to adapt to the increased complexity it introduces. Striking a balance between the comprehensive nature of the standard and the practicality of its implementation is paramount. As the cybersecurity landscape evolves, continued efforts in refining both the standard itself and the tools used to apply it will be essential in ensuring a robust and effective defense against emerging threats.