The impact of CVSS 4.0 in Software Security Vulnerability Assessment

Identifying and managing software security vulnerabilities are crucial tasks for maintaining the security of a computer system. One of the most used tools for this purpose is the CVSS (Common Vulnerability Scoring System), developed by the Forum of Incident Response and Security Teams (FIRST). Launched in 2005, subsequent versions of CVSS have made significant improvements, leading up to the current CVSS 4.0 released on October 21, 2023. This tool offers a standardized way to evaluate the severity of vulnerabilities, assigning them a score ranging from 0 to 10. However, it is important to note that the CVSS does not measure the probability of exploitation of the vulnerability, as this is influenced by factors that go beyond the pure technical aspect.

How CVSS 4.0 works

The CVSS system is structured to evaluate up to 30 variables, grouped into 4 main categories: Basic, Threat, Environmental, and Supplemental. The most common score, called CVSS-B, derives from the evaluation of the Base metrics, which in turn are divided into Exploitability and Impact. Exploitability measures the requirements necessary to exploit a vulnerability, while Impact evaluates the potential damage to system confidentiality, integrity and availability. The Threat category considers the maturity of available exploits, i.e. how easy it is for an attacker to exploit the vulnerability. Environmental customizes the impact to the specific context of the company, while Supplemental includes additional metrics such as Safety and Provider Urgency.

Vulnerability management in the business context

In the enterprise context, vulnerability management can be complex, with dozens or hundreds of potential flaws to investigate. Accurately assessing each vulnerability and prioritizing its resolution are essential but challenging processes. Often, analysis cannot be fully automated and requires manual intervention from the security team. This brings challenges such as integrating data from different tools and representing them in an understandable way. Furthermore, in certain environments it is not possible to perform automatic scans, requiring a manual search for vulnerabilities. Compatibility with existing systems and avoiding operational disruptions are additional critical factors to consider.

Prioritization of vulnerabilities and conclusions

Determining the order of vulnerabilities to patch requires a deep understanding of the business context and the impact each vulnerability could have on the core business. Vulnerabilities with the greatest risk to the business should be addressed first. This involves assigning a risk value and determining a priority index based on this value. The specific risk-based approach takes into account information relating to the vulnerability considered and its relevance for the company. In conclusion, vulnerability management is not a simple task and requires specific skills and a meticulous approach. The use of tools such as CVSS and the CVE vulnerability list can facilitate the work of security teams by providing a structured basis for risk assessment and management.