What is CVSS (Common Vulnerability Scoring System)?

Common Vulnerability Scoring System, simply referred to as CVSS, is an open framework that deals with the assessment and ranking of the security vulnerability’s severity. In this regard, scores given by the CVSS are mostly used for risk mitigation activities by cybersecurity professionals. CVSS scores are scaled between 0 and 10 to determine the level of vulnerability. A report in 2023 estimated that approximately 93% of newly reported vulnerabilities remain unanalyzed by the National Vulnerability Database (NVD), leaving an astonishingly large number of probably weaponized vulnerabilities with publicly available proof-of-concept exploits left unmanaged. This gap underlines how essential it is to have a common vulnerability scoring system, which allows organizations to take a consistent approach to assessing and prioritizing such vulnerabilities and, on that basis, take a far more proactive posture against newly emerging threats.

In this blog post, we will discuss the common vulnerability scoring system in detail. We will also explain the vulnerability scoring system, the basis for calculating a CVSS score, review the CVSS calculator, and compare it with other systems that provide support for effective vulnerability management. By the end, you will be equipped with the information needed to improve your organization’s cybersecurity posture.

What is CVSS (Common Vulnerability Scoring System)?

CVSS, or common vulnerability scoring system, is a standardized system used for the evaluation and communication of the vulnerability of software. It contains a numerical score from 0 to 10, such that the higher the value, the more severe a vulnerability is. The CVSS was launched by the National Infrastructure Advisory Council (NIAC) in 2005 as CVSS 1.0. Later, the NIAC selected the Forum of Incident Response and Security Teams, popularly known as FRONT, to handle the future developments of CVSS.

CVSS has three metric groups which are base, temporal, and environmental. These metrics help organizations to capture different aspects of a vulnerability, such as the exploitability, the widespread it could reach in systems, and its mitigation in different environments. It is through this structured approach that CVSS facilitates organizations to deal with vulnerabilities more efficiently and makes it possible to prioritize patches or mitigation strategies according to the probable impact that every flaw would make.

Why CVSS is Important for Vulnerability Management?

CVSS plays a significant role in vulnerability management, helping organizations to assess and prioritize vulnerabilities systematically. Thus, effective use of CVSS ensures the overall security of an organization where the resources are used according to their needs. Below are some factors reflecting the importance of CVSS for vulnerability management:

1. Cross-Platform Standardization: Organizations that operate large IT environments require the uniform scoring framework that CVSS offers for rating vulnerabilities across platforms and systems. Standard scoring makes it possible to judge all vulnerabilities according to the same criteria, which is a solid basis for decision-making.
2. Concentrate on Earlier Weaknesses: CVSS allows security teams to prioritize vulnerabilities based on a unified severity metric. This removes subjective bias and lets IT teams focus on the most critical vulnerabilities first. As per a report, 71% of organizations managed vulnerabilities in-house, but only 30% considered their programs highly effective. Encouragingly, 44% plan to increase investment in vulnerability management solutions, aiming to strengthen security efforts.
3. Automates Processes of Security: The CVSS score is usually provided by automated tools used in vulnerability management. Such automation tools automatically determine patching or mitigation priorities, minimizing time to patch as well as potential human error. CVSS enables the level of automation that minimizes manual risk assessment, which in turn accelerates responses.
4. Better Communication with Stakeholders: CVSS provides a common language for discussing vulnerabilities enabling IT and development teams to appropriately communicate their work with non-technical stakeholders. Shared understanding ensures everyone dealing with vulnerability management is aware of the same issues so resources can be allocated appropriately, making justification easier in security initiatives.
5. Compliance with Regulatory Needs: Using CVSS facilitates compliance with regulatory standards such as GDPR, PCI-DSS, or CCPA by allowing organizations to demonstrate proactive management of vulnerabilities. Most regulatory environments necessitate proactive vulnerability management and CVSS provides the necessary transparency to prove that security best practices are being followed. Compliance audits may be simplified when vulnerabilities are analyzed and prioritized using a common, accepted system like CVSS.
6. Informed Patch Management Decisions: Vulnerabilities with high scores should be addressed first, ensuring resources are put into mitigating the greatest risks. A survey found that 62% of organizations were unaware of their vulnerabilities before experiencing a data breach, underscoring the critical need for effective and informed patch management. By proactively addressing vulnerabilities, organizations can significantly reduce the risk of breaches and strengthen their overall security posture.

CVSS Compared to Other Vulnerability Scoring Systems

With the availability of various vulnerability scoring systems tailored to specific industries or use cases, it becomes very difficult for organizations to make a decision and select one. So, in the following section, we will compare the differences between common vulnerability scoring system and other popular scoring systems, showcasing their unique features and applications.

From these comparisons, CVSS clearly emerges as a standard applied across multiple industries. Designed for broad application, CVSS can assess vulnerabilities with unparalleled adaptability in both traditional IT systems and modern cloud-based environments. In contrast, the OWASP Risk Rating Methodology is mainly focused on web applications, relying more on subjective judgment based on potential risk and impact.

While effective within the Windows environment, Microsoft’s proprietary vulnerability scoring system does not hold the universal applicability that CVSS offers. For organizations with heterogeneous IT infrastructures, CVSS provides the flexibility to evaluate vulnerabilities consistently across platforms. Its comprehensive metrics provide a very granular assessment, enabling organizations to gain a more complete understanding of the overall risks associated with each vulnerability.

CVSS vs. CVE

Now that we know the differences with other vulnerability scoring systems, let’s compare CVSS with Common Vulnerabilities and Exposures or CVEs. The key distinction between CVSS and CVE lies in their purpose within vulnerability management. CVE provides a list of publicly known vulnerabilities with unique identifiers, while CVSS offers a scoring system to assess the severity of these vulnerabilities. Let’s understand in detail with the help of a table:

From the table above, it is clear that CVE acts as a vulnerability repository and assigns an identifier to every identified vulnerability. This makes it possible to track and share between platforms and industries. CVSS provides additional context that takes CVS’s information and assesses the severity of these vulnerabilities. Therefore, CVSS complements CVE by providing organizations with information to decide on remediation actions appropriately. While CVE answers the question of “What is the vulnerability?” CVSS answers “How severe is the vulnerability?” Both are part of a full-cycle vulnerability management process. A vulnerability identification process like CVE forms the initial step, while a context for response prioritization like CVSS follows it.

Understanding the CVSS Scoring Methodology

CVSS scoring methodology is divided into three major groups of metrics. These are Base, Temporal, and Environmental. Each contributes to the computation of all-inclusive scores reflecting an overall vulnerability. With the help of these metrics, organizations become aware of how a particular vulnerability may be exploited, the chances of it getting exploited, and the likely impact on their environment through these metrics.

Different Metrics in CVSS: Base, Temporal, and Environmental Scores

The CVSS scoring model is based on three types of metrics, together, they provide a quantification of the severity of a vulnerability. Each metric type serves a certain purpose and offers different angles from which one could appreciate the risk posed by a vulnerability. Let’s understand these metrics in detail:

1. Base Metrics: The Base metrics are the constituents of a vulnerability that remain invariant over time. They include but are not limited to, the nature of the attack vector itself, whether it is network-based, adjacent network-based, or local. The impact metrics include confidentiality, integrity, and availability. These make up the base metrics for any CVSS score.
2. Time-based Metrics: Temporal metrics take into consideration the factors that may change over time. For example, the availability of exploit code or the existence of a solution. If a patch is issued, then the Temporal metrics will update to reflect a decrease in risk. These metrics offer dynamic information, so CVSS becomes a live score, which can change as more information about the vulnerability becomes available.
3. Environmental Metrics: Environmental metrics allow the CVSS score to be tailored based on such characteristics that might apply to an affected system. These metrics help tailor the Base and Temporal scores in a way that the impact of the vulnerability is reflected in the particular environment of the organization. That is why customization is important so that organizations find the actual risk that such a vulnerability poses to them.

CVSS Score Severity Ratings: Low, Medium, High, and Critical

CVSS scores have different severity ratings, representing the range of risks a vulnerability might cause. These ratings, which are termed Low, Medium, High, and Critical, give the organization an idea of the urgency and impact in order to get an idea about the required resources for remediation. Here is what each score range means:

1. Low (0.1 – 3.9): Low-scored vulnerabilities pose minimal risk to the systems. These are the vulnerabilities that are either hard to exploit or would have very little impact should they get exploited. Organizations may decide to handle them at a later date as the chances of exploitation or the impact on core functionalities are almost negligible.
2. Medium (4.0 – 6.9): This category of vulnerabilities requires moderate effort to exploit or may have a moderate impact if the exploit is successful. Such vulnerabilities may require some degree of notice but usually will not endanger the situation. Teams should, therefore, prioritize them according to availability and current workload.
3. High (7.0 – 8.9): High-score vulnerabilities are easier to exploit, and their exploitation will affect system confidentiality, integrity, or availability. In fact, significant remediation actions are required for the resolution of these vulnerabilities because the risk of major security incidents in organizations will increase if such vulnerabilities are left without remediation for a long time.
4. Critical (9.0 – 10.0): The most threatening and the first to be addressed are critical vulnerabilities. The list of vulnerabilities consists of either easily exploitable vulnerabilities or those leading to critical damages after successful exploitation. There are some procedures most organizations implement upon the identification of critical vulnerabilities, such as emergency patches.

How Is a CVSS Score Calculated?

Obtaining a CVSS score might be a complex task for businesses as various measurements are factored into it as part of the calculation. In that structured approach, everything from vulnerability impact gets weighed very carefully. In this section, we will break down this scoring process is four stages or steps:

1. Base Metric Group Evaluation: The first step is assigning values to Base metrics that are representatives of the intrinsic properties of the vulnerability itself. These are attack vectors, attack complexity, privileges required, user interaction, and effects on confidentiality, integrity, and availability. The Base metric serves to create a first-tier risk baseline, keeping an eye on the inherent nature of a given vulnerability.
2. Group Testing of Temporal Metric: In the next step, the set of Temporal metrics is evaluated. This involves checking the current condition of the vulnerability, such as the availability of a remedy or exploit code and the report confidence. Temporal scores may change over time, representing changes in exploitability or remediation. This requires organizations to reassess the level of risk appropriately as situations evolve.
3. Customization of the Environmental Metric Group: In the third step, Environmental metrics are taken into account. This enables organizations to change the Base and Temporal scores to reflect the impact the vulnerability has on their environment. Environmental metrics introduce Security Requirements that differ from one organization to another, which makes the CVSS score a little more practical to a business’s security priorities and operational requirements.
4. Calculation of Scores Using the CVSS Calculator: After scoring all the metric groups, the final score is computed with the help of a CVSS calculator that is available on the National Vulnerability Database (NVD). This score will then describe the severity of the vulnerability so organizations can be more precise in their remediation activities.

How Organizations Can Use CVSS to Prioritize Vulnerabilities?

Prioritization of the vulnerabilities forms a major part of an effective cyber-security strategy. The CVSS scoring thus assists an organization in identifying those vulnerabilities that need immediate attention and those that can be handled later. Organizations using the CVSS in their vulnerability management can mitigate the risks systematically. Below are some ways organizations can use CVSS:

1. Scoring Intensity Ranking: High and Critical vulnerabilities, rated 7.0 and above, should immediately be remediated to reduce the risk of large-scale security breaches. This prioritization allows organizations to manage their remediation efforts by focusing resources and time on the most dangerous threats. Thus, addressing these severe vulnerabilities first would truly protect essential assets and reduce potential disruptions to the organization’s operations.
2. Remediation in Strategic Alignment with Business Objectives: Organizations should use Environmental metrics to tune the CVSS scores based on criticality, in that way enabling themselves to focus on those vulnerabilities that impact Critical Assets or Essential Functions. This aligns the remediation efforts directly in support of the key strategic business objectives. Prioritizing by impact enables organizations to maximize resource utilization because it allows them to focus on the risks that most matter to success and security.
3. Automatic Response to Vulnerabilities: Most of the vulnerability management systems are integrated with the CVSS scoring mechanism for an automated prioritization process. Such systems will be able to trigger workflows in automatic response to critical vulnerabilities while minimizing errors with CVSS. With automation, organizations can cut down on manual efforts, allowing security teams to address urgent vulnerabilities more effectively and ensure better overall security responsiveness.
4. Integrating CVSS with Threat Intelligence: By applying threat intelligence to CVSS scores, an organization will have a better understanding of real-world risk for each vulnerability in real-time. Threat intelligence data could show that a particular vulnerability is being actively exploited and, therefore, shifts priorities. In this way, the organization remains one step ahead of active attacks and can proactively protect against new, emerging threats.
5. Regular Review and Update of CVSS-based Prioritization: Organization-wide reviewing and refining of the CVSS-based prioritization should be done on a continuous basis to make sure that the strategy reflects the shifting security needs and evolving perceptions of risk. Events that may drive updated prioritization include new threat data, infrastructure changes, or changes in business goals and objectives. This regular refinement will make the vulnerability management process utilizing the precision and pertinence of CVSS to make security proactive and adaptive.

What are the Limitations of CVSS?

Although CVSS is an effective tool for the assessment of vulnerability severity, it has its own drawbacks. Knowledge of these limitations can better enable businesses for more informed decisions in terms of how to apply this technology.

Furthermore, understanding the limitations places organizations in a better position to apply complementary tools that will help bridge the gaps left behind.

1. Lack of Context-Specific Information: The CVSS itself does not inherently consider organizational-specific details. This includes business value or the particular threat landscape of an organization. Users will have to apply environmental metrics to calibrate scores appropriately in such a way that suits their particular environment and use case.
2. Subjectivity in Assigning Scores:  Some are subjective and, thus, dependent upon the experience of the scorer. For instance, Attack Complexity or Privileges Required can be very different. Therefore, this may result in vulnerabilities being over- or under-prioritized and ultimately affects the vulnerability management process efficiency. The standardized scoring guidelines minimize such risk.
3. Does Not Consider Exploitability Trends: Although Temporal metrics vary depending on exploitability, CVSS does not consider how attack trends may influence future risks. A vulnerability may have a very low score but become even more dangerous based on new exploits developed with the passing of time. That is why supplementing CVSS with threat intelligence tools is indispensable for a deeper understanding.
4. Limited Insight into the Interaction Between Vulnerabilities: Scoring through the CVSS alone does not take into account the compounding effects of combined vulnerabilities. Large, complex attack graphs that are used to exploit many vulnerabilities are significantly riskier than their score representation alone. This also will need to be complemented with either an attack path analysis or a pen testing approach in order to identify and fix such compounded risks.
5. Static Nature of Scoring: The problem with the CVSS scores is that they become a point-in-time snapshot. The scores don’t update themselves with respect to changes within the threat landscape or changes in surroundings an organization is part of. It is in this ‘static’ nature that some assessments become quite out-of-date, particularly in vulnerabilities that change so rapidly.
6. Minimum Guidance to Prioritize Under Diverse Environments: CVSS alone cannot provide proper prioritization guidance for diverse environments with differing regulatory or operational requirements. For instance, certain financial-area vulnerabilities may require immediate remediation for compliance issues; in other industries, they may be less critical. Organizations should base CVSS in conjunction with industry-specific risk factors to make sure that compliance and operational priorities remain aligned with these risk factors.

Common Vulnerability Scoring System (CVSS) Best Practices

CVSS’s best practice usage by organizations assists in maximizing its utility while effectively handling its limitations. Such practices ensure that consistent application should allow security teams to focus on and mitigate appropriately when it matters the most.

Here are some CVSS best practices:

1. Integration of CVSS Scores and Threat Intelligence: The inclusion of CVSS scores in current threat intelligence improves the view of vulnerabilities and sets up real risk assessments. It gives room to other aspects, such as trends or more active threats. Hence, this approach to managing vulnerabilities is dynamic and responsive.
2. Environmental Metrics Use: The effective use of Environmental metrics can tailor the score to the specific situation of the organization. This tailoring bridges the gap between generic scoring and organization-specific risk management, ensuring that limited resources are deployed where they will have the most impact.
3. CVSS Scores Are Frequently Updated: The actual problem is that the CVSS scores used need to be constantly updated as the vulnerabilities evolve. The development of Temporal metrics thus ensures that scores for ongoing vulnerabilities reflect current exploitability and patch availability. This allows remediation strategies to adapt to dynamic changes in the vulnerability landscape.
4. Prioritization Based on the Criticality of Assets: The use of the CVSS, in addition to asset criticality, will bring it into sharp focus while creating mitigation strategies. Matching the CVSS score with asset values or criticality enables security teams to focus on the vulnerabilities whose exploitation would have a high impact. This approach ensures, in turn, that the most risky assets will receive consideration and thus provide protection in the places where that protection is needed most.
5. Collaboration Across Security Functions: A common drive towards vulnerability management is ensured by the engagement of different security functions like risk management and incident response in interpreting the meanings of the scores. The cross-functional teams work to ensure that the CVSS score is applied in each instance for immediate threat assessment and also for long-term strategic planning. This aligns actions across teams for overall security posture.
6. Combining CVSS with Remediation Timelines: Establishing remediation timelines based on CVSS scores allows structured response efforts and helps them avoid delays. Organizations will map the CVSS score to certain response times to enforce timely remediation policies, meaning vulnerabilities are handled predictably and in an efficient manner. This structured approach permits proactive resource planning and accountability across a security team.

Real-World Examples of CVSS in Action

The real-world examples of CVSS in practice can help demonstrate the relevance of CVSS  to businesses, allowing them to get practical knowledge of the concept. Some examples of widely known vulnerabilities are given below along with their related CVSS scores and what they may mean for an organization:

1. Heartbleed (CVE-2014-0160): Heartbleed is a vulnerability in the OpenSSL cryptographic software library with a CVSS Base score stood at 7.5. This vulnerability made it possible for attackers to take advantage of the heartbeat functionality to read sensitive data directly from the memory of servers affected by this vulnerability, including private keys and user credentials. Such a high score indicated a high impact on confidentiality, thus forcing organizations to prioritize immediate patching efforts. The widespread vulnerability made a significant number of websites, which led to a strong push toward improved security practices and awareness in the industry. This could also lead to massive data breaches coupled with identity theft, prompting remediation.
2. Windows SMB Remote Code Execution Vulnerability (CVE-2017-0144): CVSS for this vulnerability was rated 8.8 high because it allowed remote code execution within Windows systems. Indeed, WannaCry ransomware affected hundreds of thousands of computers around the globe because it used this attack tool, which exploited a vulnerability within Microsoft’s implementation of Server Message Block (SMB). This vulnerability enabled attackers to access systems without authentication and execute arbitrary code. The score clearly showed a need for immediate patching and system updates, thereby pointing to how swiftly cybercriminals exploit similar vulnerabilities in software or systems. It encourages further robust security measures to be put in place so that such exploits do not take place in the future.
3. Shellshock (CVE-2014-6271): Shellshock is a Bash shell vulnerability that had scored a CVSS of 9.8 and, thus, ranked critical. Using environment variables, hackers were able to run any kind of command on Unix-based systems. The scale of this vulnerability was of utmost importance as multiple devices were in danger, so system administrators across the world rushed to immediate action. The remote entry points were not authenticated and the system had very few controls on many entry points. It was highly vulnerable to threats in terms of integrity and confidentiality. Organizations were forced to implement quick fixes with expansive security measures against future recurrence.
4. Log4Shell (CVE-2021-44228): Log4Shell is a vulnerability based on the weakness of the Log4j logging library, scoring a critical CVSS score of 10, allowing an attacker to achieve arbitrary code execution on servers that implement the library when receiving specially crafted log messages. Such a high-exposure vulnerability applied in numerous applications across thousands of packages warranted extensive emergency patching within those sectors. Organizations had to operate under extreme pressure to safeguard their systems against potential exploitation, and failure to patch meant very serious breaches of data and operational disruption. The event brought forth the necessity of maintaining updates on the software library and always being on the lookout for such vulnerabilities.
5. Spectre and Meltdown (CVE-2017-5754): Spectre and Meltdown are microprocessor vulnerabilities that have rated 5.6 on the CVSS scale due to the deep implications they bring related to data privacy and system integrity. Such flaws in the architecture of the CPU permit an attacker to access information held within memory across various applications. Remediation was rather challenging as it demanded a combination of software patches as well as architectural changes at the hardware level, which was problematic for organizations all over the world. It led to further study on hardware security and advancement in proactive measures for mitigating those risks associated with emerging threats within computing technology.

How SentinelOne Can Help?

SentinelOne plays a critical role in improving the management of vulnerabilities for organizations against the assessment of the CVSS. The company lets the security teams prioritize vulnerabilities due to the potential impact that could occur and exploitability, given that the product integrates the scores from its platform with the CVSS. This means that for the platform, matching active threats with relevant CVSS metrics will enable the giving of attention to the highest-risk vulnerabilities to be made immediately.

For instance, if a vulnerability is rated high in severity, then SentinelOne’s proactive detection mechanisms can immediately ascertain whether any endpoints are affected, so remediation can occur quickly before an exploit occurs. This capability is handy in countering the risks associated with zero-day vulnerabilities, as the exposure window is critical.

SentinelOne’s AI security posture management features provide better visibility into an organization’s security posture. With insights from vulnerabilities in the environment, security teams can know which assets are most vulnerable. It can recommend patching schedules based on the CVSS scores of identified vulnerabilities and optimize remediation.

SentinelOne’s automated threat response capabilities can quickly remediate exploited vulnerabilities. It can contain and remediate threats in real time by reducing the chance of breaking through security. Efficiency in dealing with vulnerabilities helps organizations comply with industry regulations and strengthens their security strategy.

Conclusion

In conclusion, we have understood how CVSS has become a standard for the assessment and management of vulnerabilities in diverse systems. The application of Base, Temporal, and Environmental metrics enables an organization to apply the same methodology in vulnerability management. Such a regimented approach allows for proper prioritization and resource allocation, not only to make informed decisions but also to effectively manage them. While the shortcomings of CVSS are recognized, threat intelligence and asset criticality transform it into a basic tool in security posture improvement and compliance provisions with minimal disruption.

For businesses seeking to advance their processes of vulnerability management, SentinelOne offers an all-encompassing solution that makes the integration of CVSS workflows easier, faster, and more efficient in threat detection, assessment, and response in real time. SentinelOne Singularity™ platform works with your existing security infrastructure to provide actionable insights and rapid response to keep your systems resilient. Reach out to SentinelOne today to explore how we can support your cybersecurity goals with tailored proactive solutions.

FAQs

1. What is a Common Vulnerability Scoring System?

Common Vulnerability Scoring System is a standardized framework that evaluates and communicates the severity of software vulnerabilities. It provides an organization with a numerical score between 0 and 10, which enables organizations to understand the potential impact of vulnerabilities on their systems and data. This system is widely used in order to prioritize vulnerabilities in cybersecurity efforts and facilitate effective risk management.

2. What is the CVSS score for?

CVSS score is used to rate the vulnerability based on how severe it is and by which an organization determines to allocate its resources to proper remediation, ensuring most vulnerabilities are remediated for their potential damage and overall bettering of their security.

3. What is the CVSS risk assessment tool?

The CVSS risk assessment tool calculates the severity of vulnerabilities on several different metrics. This enables an organization to compare the risks associated with different vulnerabilities and helps in making the right decisions about vulnerability management. It thus forms a more systematic approach to improvement in overall security.

4. How is CVSS score calculated?

The CVSS score is arrived at as a sum of metrics comprising three categories. These include Base, Temporal, and Environmental, which score the inherent attributes of the vulnerability, change with time, or depend on environmental factors relevant to the specific context in the user environment. An aggregation of these scores will give the final CVSS score.

5. Why do Businesses use CVSS?

CVSS helps businesses make the process of managing vulnerabilities much easier by giving them a uniform and standardized way of measuring the severity of a vulnerability. It enables businesses to prioritize remediation, improve their posture in cybersecurity, and keep in line with regulatory compliance.