A vulnerability is any aspect of a design , architecture or configuration of a device that allows cyber criminals to conduct attacks, manipulate services, and steal data. There are various methods available for rating vulnerabilities to assess their risk level. The Common Vulnerability Scoring System (CVSS) is the industry standard most used for this purpose.
What is a Growing Scoring Method for Vulnerability?
There are several ways of determining the extent of a weakness. The That Vulnerability Scoring System (CVSS), a collection of open standards to allocate a severity score to a vulnerability, is one way forward. Scores range between 0.0 and 10.0, with higher numbers reflecting a higher degree of severity of vulnerability.
The National Vulnerability Database (NVD), Computer Emergency Response Teams (CERT) and others use the CVSS ratings to determine the effects of vulnerabilities. Many security firms have set up their own scoring systems, too. There are three versions of CVSS, the most recent is CVSSv3.1, released in 2019.
What Is Vulnerability Causing?
Vulnerabilities can be created by human error or by misapplied security measures. Hackers use vulnerabilities to exploit a blindspot defense, and then launch attacks. Hackers, for example, may gain access to root credentials and cause corporate data to be stolen or deleted. Each vulnerability typically provides hackers with various types of exploits. Many of those bugs are caused by human error, but hackers build some of them.
The most common errors and attacks that often create vulnerabilities are briefly reviewed here:
- Complexity — complex systems increase the likelihood of failure due to malfunction or unauthorized access.
- Familiarity — common code, operating systems, and hardware improve an attacker’s chances of finding information on known vulnerabilities.
- Connectivity — connected devices often have a greater chance of becoming vulnerable due to weak security measures.
- Flaws in the operating system — Operating systems like any program can have flaws. Vulnerable operating systems generally give every user full access. Malware, and viruses can therefore execute malicious commands.
- Software bugs — programmers may intentionally or accidentally build a bug that exploits all of the software.
- People — to gain access to passwords and confidential and corporate data, hackers employ methods involving attacks on social engineering and insider threats. They trick, threaten or exploit human resources to disclose information.
How does CVSS Scoring work
CVSS is made up of three general metric groups — base, time, and setting. As explained in more detail below, each of these metrics is composed of different elements.
Base Score
The base-score metric is a list of some of the vulnerability ‘s native properties. Native properties don’t change over time, and don’t depend on the vulnerability environment. The base score is based on a formula that takes into account two subscores — the effect subscore, and the sub-score on exploitability.
Exploitability subscore
The subscore on exploitability represents the ease and technical means by which an attacker can exploit a vulnerability. CVSS rates the extent of a vulnerability using specific metrics:
- Attack vector (AV)—describes an attacker’s accessibility to the weakness. A weakness that can be accessed via a local network gets a higher AV score. A weakness requiring an attacker to be physically present in order to execute an attack earns lower scores.
- Complexity of Attack (AC)—defines the conditions which may prevent vulnerability exploitation. A high score indicates that before performing an attack , the attacker may need to collect additional information about a given target. A low score means an attacker can exploit a vulnerability regularly, without any special conditions.
- Necessary Privileges (RP)—describes the amount of privileges an attacker requires to execute. A high score suggests the attack could only impact files and user-level settings. Low scores mean the attacker needs administrative privileges to take advantage of the vulnerability.
- User Interaction (UI)—defines whether the attacker wants a particular user to engage in the attack. The score is binary, either it needs interaction or it is not.
Impact subscore
A subscore for impact determines the effect of a successful exploit. The most significant effect factor is the metric of reach of authorisation (S). This measure shows the effect on certain resources or elements of a weakness being exploited. The S metric is binary, meaning that a vulnerability allows the attacker to affect systems with different privileges, or it only impacts the resources at the same privilege point. The effect metric represents the following three values, if the scope measure is not available:
- Confidentiality (C) — specifies the degree of authority of a weakness that has been abused. An exploit may result in a low degree of loss of confidentiality where there is some indirect access to restricted information. An exploit can also lead to a high degree of failure leading to severe misuse of sensitive data. Login password and username of an administrator, for example.
- Integrity (I)—defines the extent of corruption in the data following an attack. A low score means that some data have been updated but there are no significant impacts. A high score suggests a full data security breach, or the changed data will have a major effect on compromised device functionality.
- Availability (A)—a measure of the lack of availability for the impacted component’s services or resources. Low scores show minor impact, or no effect whatsoever. High scores suggest a persistent interruption, or a complete lack of control.
Temporal Score
Temporal score metrics measure the current state of availability of code, exploit methods, and any fixes or alternative solutions exist.
- Exploit technology maturity (E)—reflects the available techniques or technology that can be used by an attacker to exploit the vulnerability. Over time the score improves.
- Remediation level (RL) – tests the degree of remediation available for the vulnerability exploited.
- Test Trust (RC)—defines the degree to which a vulnerability test is reliable. Vulnerabilities may be found by third parties but may not be recognized by official vendor of the product. It is also possible to identify vulnerabilities but their origin would remain unknown.
Environmental Metrics
Environmental metrics allow you to customize the CVSS score based on the significance of the resources affected. The score is calculated in terms of the nature of CIA (integrity, confidentiality , and availability) alternative security controls. The updated version of base metrics is environment ratings. The metric values are based on the organisation’s infrastructure portion placement:
The potential for collateral damage (CDP)—reflects the potential for loss of physical properties due to injury or theft, or loss of income and productivity.
Goal distribution (TD)-the number of insecure devices in the world of your customer.
Confidentiality condition (CR) — the extent of effect of loss of confidentiality when leveraging a weakness on this asset.
Credibility Criterion (IR)—determines the extent of effect of the loss of integrity when successfully exploiting a vulnerability.
Requirement for availability (AR)—measures the degree of impact to the availability of the properties.
Conclusion
CVSS consists of three classes of metrics: basis, setting, and temporal. The base score tests the extent of a deficiency according to its indigenous characteristics. The temporal metrics modify the base score based on variables that vary over time, including exploit availability. The environmental measures adapt the temporal and base metrics to a particular computing environment. The advantages of CVSS include the availability of a consistent vulnerability scoring framework for agnostic platforms and vendors.
