What is CVSS? How does it help in vulnerability assessment?

Cybersecurity and CVSS

Cybersecurity is crucial to organizations to ensure that their network remains secure and unharmed by attack actors. One of the vital steps that involve the process of testing and analysing a network for weak areas of breach points is called Vulnerability Assessment Penetration Testing (VAPT). This plays a vital role in unravelling the exploitable loopholes in an application that are used by attack actors to hack through and cause the organization huge losses on money, customers, reputation, and lawsuits. There is a way to gauge the severity of the vulnerabilities and suggest appropriate recommendations to the organizations to prevent them from being exploited. This blog will help us understand the necessity of CVSS (Common Vulnerability Scoring System) that enables the security team to scale the intensity of the vulnerabilities and help prevent them.

What is CVSS?

CVSS is the abbreviation of the term Common Vulnerability Scoring System. It is a form of scoring estimation that is used to measure the severity of vulnerabilities that a software or an application is exposed to. CVSS is an initiative brought forth by an international organization known as the Forum of Incident Response and Security Teams, also shortly called the FIRST, a team of trusted security computer researchers and scientists who are involved in the task of creating tools and best practices to make the efforts of the incident response teams a bit easy and more efficient. They also bring forth the methodologies and standard security policies to be followed by incident response teams.

FIRST has worked on something known as the Security Interest Group (SIG), which would be the developers and the maintainers of the CVSS, to enable teams to understand and prioritize the severity of a security vulnerability. FIRST is also responsible for publishing scores according to the guidelines to make it easy for the teams to report the vulnerabilities based on this.

What is CVSS used for?

There used to be a time when organizations used to implement their own scale to measure security vulnerabilities. To bring uniformity to this process, the CVSS was introduced for the first time. Today with the help of CVSS, organizations simply gauge the impact of the security vulnerability bases on the scope that the CVSS approves. This system makes it easy to measure the vulnerability and, based on the score from the CVSS, prioritize it to find quicker solutions.

What are the metrics of the CVSS?

As any other feature, CVSS also underwent a lot of changes over time and the current version is CVSS v3.1, which is being used for security vulnerabilities. There is a standardized framework that provides the scores for the vulnerabilities in accordance with the areas they fall under. There are three metrics under which the CVSS scores can be divided:

Base Metrics: The impact and the assessment of this metric does not depend on the time of the vulnerability, but it depends on the ease of exploitation of the vulnerability.

Temporal Metrics: This depends on circumstances that affect the vulnerability.

Environmental Metrics: These are metrics that enable customizing the scare to impact the user’s specific environment.

What are these CVSS metrics based on?

Exploitability: These are metrics that are based on the characteristics of the vulnerable components. This is further divided into four sub-sections, which are:

Attack vector: This metric is based on the level of access required to exploit a vulnerability. If the score is high, it means that the vulnerability is severe. But if the score is low, it means that the possibility of exploiting the vulnerability on-premise is low.

Attack complexity: A metric that is based on the things that are out of the control of the attacker, such as a key theft or a middleman attack. The higher the score, the higher the chances of being exploited by an attacker.

Required privileges: This metric is based on the attacker’s privilege to exploit a vulnerability. The higher the score, the more possibilities that the vulnerability is taken up as a privilege and exploited.

User interaction: A metric that is based on the need to recruit a willing attacker to exploit the vulnerability and finish the task. The higher the score, the more chances of this vulnerability being exploited.

Scope: This is a metric that is based on using several components to exploit a vulnerability. A higher score represents that the exploitation will go deeper and affects other backend system attacks.

Impact: This is a metric that is based on the outcome of other attack results. There are three sub-sectors to this, they are:

Confidentiality: This is the metric that is based on the amount of data that the attacker has access to. The higher the score, the more risk of being attacked.

Integrity: A metric is based on the ability of the attackers to alter the data and exploit the system. If the score is high, the attackers can completely exploit and modify the data.

Availability: This is a metric based on the loss of a system once it is exploited. The higher the score, the higher the chances of an authorized person accessing it as the attacker takes control.

Conclusion

CVSS is a very important method for figuring out how to identify the most severely affecting vulnerability. When this is combined with threat intelligence, it will effectively enable to identify the specific threats. This will help to concentrate on the most critical risks that businesses are exposed to and the attack actors look out for to exploit the threats. This will help in enhancing the remedies for the businesses rather than worrying and waiting around for an attacker to seize their moment, thereby drastically lowering the attack surface.