homepage
Open menu
Contact Sales
Go one level top
  • Train and Certify
    Train and Certify

    Immediately apply the skills and techniques learned in SANS courses, ranges, and summits

    • Overview
    • Courses
      • Overview
      • Full Course List
      • By Focus Areas
        • Cloud Security
        • Cyber Defense
        • Cybersecurity and IT Essentials
        • DFIR
        • Industrial Control Systems
        • Offensive Operations
        • Management, Legal, and Audit
      • By Skill Levels
        • New to Cyber
        • Essentials
        • Advanced
        • Expert
      • Training Formats
        • OnDemand
        • In-Person
        • Live Online
      • Free Course Demos
    • Training Roadmaps
      • Skills Roadmap
      • Focus Area Job Roles
        • Cyber Defense Job Roles
        • Offensive Operations Job Roles
        • DFIR Job Roles
        • Cloud Job Roles
        • ICS Job Roles
        • Leadership Job Roles
      • NICE Framework
        • Security Provisionals
        • Operate and Maintain
        • Oversee and Govern
        • Protect and Defend
        • Analyze
        • Collect and Operate
        • Investigate
        • Industrial Control Systems
      • European Skills Framework
    • GIAC Certifications
    • Training Events & Summits
      • Events Overview
      • In-Person Event Locations
        • Asia
        • Australia & New Zealand
        • Latin America
        • Mainland Europe
        • Middle East & Africa
        • Scandinavia
        • United Kingdom & Ireland
        • United States & Canada
      • Live Online Events List
      • Summits
    • OnDemand
    • Get Started in Cyber
      • Overview
      • Degree and Certificate Programs
      • Scholarships
      • Free Training & Resources
    • Cyber Ranges
  • Enterprise Solutions
    Manage Your Team

    Build a world-class cyber team with our workforce development programs

    • Overview
    • Group Purchasing
    • Build Your Team
      • Assessments
      • Private Training
      • By Industry
        • Health Care
        • Industrial Control Systems Security
        • Military
    • Leadership Training
      • Leadership Courses
      • Executive Cybersecurity Exercises
  • Security Awareness
    Security Awareness

    Increase your staff’s cyber awareness, help them change their behaviors, and reduce your organizational risk

    • Overview
    • Products & Services
      • Security Awareness Training
        • EndUser Training
        • Phishing Platform
      • Specialized
        • Developer Training
        • ICS Engineer Training
        • NERC CIP Training
        • IT Administrator
      • Risk Assessments
        • Knowledge Assessment
        • Culture Assessment
        • Behavioral Risk Assessment
    • OUCH! Newsletter
    • Career Development
      • Overview
      • Training & Courses
      • Professional Credential
    • Blog
    • Partners
    • Reports & Case Studies
  • Resources
    Resources

    Enhance your skills with access to thousands of free resources, 150+ instructor-developed tools, and the latest cybersecurity news and analysis

    • Overview
    • Webcasts
      • Webinars
      • Live Streams
        • Wait Just An Infosec
        • Cybersecurity Leadership
        • SANS Threat Analysis Rundown (STAR)
    • Free Cybersecurity Events
      • Free Events Overview
      • Summits
      • Solutions Forums
      • Community Nights
    • Content
      • Newsletters
        • NewsBites
        • @RISK
        • OUCH! Newsletter
      • Blog
      • Podcasts
        • Blueprint
        • Trust Me, I'm Certified
        • Cloud Ace
        • Wait Just an Infosec
      • Summit Presentations
      • Posters & Cheat Sheets
    • Internet Storm Center
    • Research
      • White Papers
      • Security Policies
    • Tools
    • Focus Areas
      • Cyber Defense
      • Cloud Security
      • Digital Forensics & Incident Response
      • Industrial Control Systems
      • Cyber Security Leadership
      • Offensive Operations
      • Open-Source Intelligence (OSINT)
  • Get Involved
    Get Involved

    Help keep the cyber community one step ahead of threats. Join the SANS community or begin your journey of becoming a SANS Certified Instructor today.

    • Overview
    • Join the Community
    • Work Study
    • Teach for SANS
    • CISO Network
    • Partnerships
    • Sponsorship Opportunities
  • About
    About

    Learn more about how SANS empowers and educates current and future cybersecurity practitioners with knowledge and skills

    • SANS
      • Overview
      • Our Founder
      • Awards
    • Instructors
      • Our Instructors
      • Full Instructor List
    • Mission
      • Our Mission
      • Diversity
      • Scholarships
    • Contact
      • Contact Customer Service
      • Contact Sales
      • Press & Media Enquiries
    • Frequent Asked Questions
    • Customer Reviews
    • Press
    • Careers
  • Contact Sales
  • SANS Sites
    • Australia
    • Brazil
    • France
    • India
    • Japan
    • Middle East & Africa
    • United Kingdom
  • Search
  • Log In
  • Join
    • Account Dashboard
    • Log Out
  1. Home >
  2. Blog >
  3. What is Common Vulnerability Scoring System (CVSS)
Jonathan_Risto_370x370.png
Jonathan Risto

What is Common Vulnerability Scoring System (CVSS)

CVSS stands for the Common Vulnerability Scoring System

May 22, 2023

What is Common Vulnerability Scoring System (CVSS)

CVSS stands for the Common Vulnerability Scoring System. It's a way to evaluate and rank reported vulnerabilities in a standardized and repeatable way. The goal of CVSS is to help you compare vulnerabilities in different applications – and from different vendors - in a standardized, repeatable, vendor agnostic approach.

CVSS generates a score from 0 to 10 based on the severity of the vulnerability. A score of 0 means the vulnerability is less significant than the highest vulnerability with a score of 10, if you're only using CVSS. By using CVSS to prioritize vulnerabilities, you can focus on the most critical ones first and reduce the overall risk to your organization.

CVSS values have been grouped as well into the rankings that you may have seen, of Critical, High, Medium, and Low.For CVSS v3, they are as follows:

CVSS Base ScoreCVSS Severity Level
0None
0.1 - 3.9Low
4.0 - 6.9Medium
7.0 - 8.9High
9.0 - 10.0Critical

The above is what is defined within the CVSS documentation, which can be found on the FIRST website.

What is all taken into account to generate the CVSS score?

That is a great question, and it is a slightly more complex question to answer than what is CVSS. The CVSS score combines a lot of factors to be able to generate a score. Those factors are:

  • Attack Vector
  • Attack Complexity
  • Privileges Required
  • User Interaction
  • Scope
  • Confidentiality
  • Integrity
  • Availability

That’s a lot of things that go into the mix. Now let’s dig a little deeper into each of these.

Attack Vector

The attack vector has 4 different values that can be assigned to it:

  • Network,
  • Adjacent,
  • Local, or
  • Physical.

Think of these as how the attacker can access the system in system in question. Ranging from anywhere to I need to physically connect something to the system. A network value here will generate the highest CVSS value.

Attack Complexity

Attack Complexity comes down to how hard it is to exploit the vulnerability.Two possible values exist for this, which are:

  • Low or
  • High.

The low attack complexity will generate the highest score.

Privileges Required

This outlines what privileges the attacker needs to have BEFORE exploiting the vulnerability. Possible values are:

  • None,
  • Low, or
  • High.

None is no access to any settings or files on the system.Low is basic user capabilities.High is administrative level privileges are needed.

User Interaction

This defines how a user needs to be engaged somehow to successfully exploit the vulnerability. The options here are:

  • None or
  • Required.

When no user is required the impact on the CVSS score is highest.

Scope

This is a slightly harder sub-component to understand. Here it is trying to measure if the vulnerability can impact items that are outside of the security authority of the affected component. A security authority is something that controls access to objects under its control. Examples of a security authority could be an application (controls how things work inside the application), an operating system (controls how things work within the environment). Values here are:

  • Unchanged or
  • Changed,

A scope change haS the largest impact.

Confidentiality

Confidentiality is the potential for unauthorized access to sensitive information. The possible values are:

  • High,
  • Low, or
  • None.

The greatest impact comes from the High value, or total confidentially being lost.

Integrity

This component measures the potential for unauthorized modification, a data breach or deletion of data. Potential values are:

  • High,
  • Low, or
  • None.

High is the most severe.

Availability

Availability attempts to measure the potential for denial of access to authorized users. This could be the denial access to a service or processor cycles. Potential values for Availability are:

  • High,
  • Low, or
  • None.

High is the most severe.

Now that we know all the components, we could dive into how all of this is calculated, but to be honest, the majority of people don’t need to know this level of information. Why? Because the majority of tools calculate this for us. But if you REALLY want to know the values of each of the above components, feel free to look at the documentation HERE. And if you want to see how to calculate these all manually, take a look at the documentation and formulas HERE

Suppose you did want to try some calculations. In that case, there are numerous calculators available online, but one that FIRST puts out is found HERE. You can select the values for each component listed above, and see the final CVSS score.

History of CVSS: Are you using v1 or v2 or v3.1?

In 2003/2004, the original CVSS was released by the National Infrastructure Advisory Council (NIAC) and they selected the Forum of Incident Response and Security Teams (FIRST) to become the custodian of CVSS. This was done in April 2005.

Version 2 of the specification was released in 2007 and V3 in 2015. The current version that is being used is 3.1, released in 2019. Updates were done based on feedback received to help improve the overall value of CVSS.

Why does this matter? Well, some of the tools we use today display different information. Some show CVSS v2 scores, some show CVSS v3 scores. Some display both. You must be careful when looking at vulnerabilities and their CVSS scores to know which is being used.

For example, the same CVE is shown in the two pictures below (from the NVD website, and you can see the same CVE by going HERE). The top one is showing v3 scores, and the bottom one shows v2 scores.

Image of CVE v3 scoring

Image of CVE v2 scoring

As you can see, two different values come out of the formula depending on which version of CVSS is being used. The v3 value is 5.5, ranking a MEDIUM score while the v2 score is 2.1, earning a LOW ranking.

If you were prioritizing based on CVSS alone, this would most likely fall into two different remediation timeframes for your organization. Not overly consistent, which isn’t good.

Conclusion: CVSS improves security by helping you find vulnerabilities

Hopefully, this has helped you understand what CVSS is and how the score is generated. While CVSS is an important tool for determining which vulnerabilities to remediate first, it's only one piece of a much larger vulnerability management puzzle. Most organizations use multiple sources of information to assess and prioritize vulnerabilities, not just CVSS scores.

That said, understanding how CVSS works and what factors contribute to the score can be extremely useful. By using the CVSS score in conjunction with other information, you can make better informed decisions about which vulnerabilities to address and in what order.

About the Author

With a career spanning over 20 years that has included working in network design, IP telephony, service development, security and project management, Jonathan has a deep technical background that provides a wealth of information he draws upon when teaching. Currently, Jonathan works for the Canadian Government conducting cyber security research in the areas of vulnerability management and automated remediation. He is also an independent security consultant. Jonathan is a co-author and instructor for SANS MGT516: Building and Leading Vulnerability Management Programs. Learn more about Jonathan.

Share:
TwitterLinkedInFacebook
Copy url Url was copied to clipboard
Subscribe to SANS Newsletters
Receive curated news, vulnerabilities, & security awareness tips
United States
Canada
United Kingdom
Spain
Belgium
Denmark
Norway
Netherlands
Australia
India
Japan
Singapore
Afghanistan
Aland Islands
Albania
Algeria
American Samoa
Andorra
Angola
Anguilla
Antarctica
Antigua and Barbuda
Argentina
Armenia
Aruba
Austria
Azerbaijan
Bahamas
Bahrain
Bangladesh
Barbados
Belarus
Belize
Benin
Bermuda
Bhutan
Bolivia
Bonaire, Sint Eustatius, and Saba
Bosnia And Herzegovina
Botswana
Bouvet Island
Brazil
British Indian Ocean Territory
Brunei Darussalam
Bulgaria
Burkina Faso
Burundi
Cambodia
Cameroon
Cape Verde
Cayman Islands
Central African Republic
Chad
Chile
China
Christmas Island
Cocos (Keeling) Islands
Colombia
Comoros
Cook Islands
Costa Rica
Croatia (Local Name: Hrvatska)
Curacao
Cyprus
Czech Republic
Democratic Republic of the Congo
Djibouti
Dominica
Dominican Republic
East Timor
Ecuador
Egypt
El Salvador
Equatorial Guinea
Eritrea
Estonia
Ethiopia
Falkland Islands (Malvinas)
Faroe Islands
Fiji
Finland
France
French Guiana
French Polynesia
French Southern Territories
Gabon
Gambia
Georgia
Germany
Ghana
Gibraltar
Greece
Greenland
Grenada
Guadeloupe
Guam
Guatemala
Guernsey
Guinea
Guinea-Bissau
Guyana
Haiti
Heard And McDonald Islands
Honduras
Hong Kong
Hungary
Iceland
Indonesia
Iraq
Ireland
Isle of Man
Israel
Italy
Jamaica
Jersey
Jordan
Kazakhstan
Kenya
Kiribati
Korea, Republic Of
Kosovo
Kuwait
Kyrgyzstan
Lao People's Democratic Republic
Latvia
Lebanon
Lesotho
Liberia
Liechtenstein
Lithuania
Luxembourg
Macau
Macedonia
Madagascar
Malawi
Malaysia
Maldives
Mali
Malta
Marshall Islands
Martinique
Mauritania
Mauritius
Mayotte
Mexico
Micronesia, Federated States Of
Moldova, Republic Of
Monaco
Mongolia
Montenegro
Montserrat
Morocco
Mozambique
Myanmar
Namibia
Nauru
Nepal
Netherlands Antilles
New Caledonia
New Zealand
Nicaragua
Niger
Nigeria
Niue
Norfolk Island
Northern Mariana Islands
Oman
Pakistan
Palau
Palestine
Panama
Papua New Guinea
Paraguay
Peru
Philippines
Pitcairn
Poland
Portugal
Puerto Rico
Qatar
Reunion
Romania
Russian Federation
Rwanda
Saint Bartholemy
Saint Kitts And Nevis
Saint Lucia
Saint Martin
Saint Vincent And The Grenadines
Samoa
San Marino
Sao Tome And Principe
Saudi Arabia
Senegal
Serbia
Seychelles
Sierra Leone
Sint Maarten
Slovakia
Slovenia
Solomon Islands
South Africa
South Georgia and the South Sandwich Islands
South Sudan
Sri Lanka
St. Helena
St. Pierre And Miquelon
Suriname
Svalbard And Jan Mayen Islands
Swaziland
Sweden
Switzerland
Taiwan
Tajikistan
Tanzania
Thailand
Togo
Tokelau
Tonga
Trinidad And Tobago
Tunisia
Turkey
Turkmenistan
Turks And Caicos Islands
Tuvalu
Uganda
Ukraine
United Arab Emirates
United States Minor Outlying Islands
Uruguay
Uzbekistan
Vanuatu
Vatican City
Venezuela
Vietnam
Virgin Islands (British)
Virgin Islands (U.S.)
Wallis And Futuna Islands
Western Sahara
Yemen
Yugoslavia
Zambia
Zimbabwe

By providing this information, you agree to the processing of your personal data by SANS as described in our Privacy Policy.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Recommended Training

  • LDR516: Building and Leading Vulnerability Management Programs
  • LDR521: Security Culture for Leaders
  • MGT414: SANS Training Program for the CISSP Certification

Tags:
  • Security Management, Legal, and Audit

Related Content

Blog
CurriculumTile_340_x_340.png
Security Management, Legal, and Audit
May 4, 2023
Vulnerability Management Maturity Model – Self-Assessment Tool (VMMM-SAT)
A way to help determine your vulnerability management maturity level.
Jonathan_Risto_370x370.png
Jonathan Risto
read more
Blog
CurriculumTile_340_x_340.png
Security Management, Legal, and Audit
April 25, 2023
SANS Cybersecurity Leadership Curriculum
Developing World Class Cybersecurity Leaders
MGT_Triad_370x370_Headshot.jpg
SANS Cybersecurity Leadership
read more
Blog
csl-340x340-logo.jpg
Security Management, Legal, and Audit, Penetration Testing and Red Teaming
May 2, 2022
Vulnerability Management Resources
Stay current with free resources focused on vulnerability management.
MGT_Triad_370x370_Headshot.jpg
SANS Cybersecurity Leadership
read more
  • Register to Learn
  • Courses
  • Certifications
  • Degree Programs
  • Cyber Ranges
  • Job Tools
  • Security Policy Project
  • Posters & Cheat Sheets
  • White Papers
  • Focus Areas
  • Cyber Defense
  • Cloud Security
  • Cybersecurity Leadership
  • Digital Forensics
  • Industrial Control Systems
  • Offensive Operations
Subscribe to SANS Newsletters
Receive curated news, vulnerabilities, & security awareness tips
United States
Canada
United Kingdom
Spain
Belgium
Denmark
Norway
Netherlands
Australia
India
Japan
Singapore
Afghanistan
Aland Islands
Albania
Algeria
American Samoa
Andorra
Angola
Anguilla
Antarctica
Antigua and Barbuda
Argentina
Armenia
Aruba
Austria
Azerbaijan
Bahamas
Bahrain
Bangladesh
Barbados
Belarus
Belize
Benin
Bermuda
Bhutan
Bolivia
Bonaire, Sint Eustatius, and Saba
Bosnia And Herzegovina
Botswana
Bouvet Island
Brazil
British Indian Ocean Territory
Brunei Darussalam
Bulgaria
Burkina Faso
Burundi
Cambodia
Cameroon
Cape Verde
Cayman Islands
Central African Republic
Chad
Chile
China
Christmas Island
Cocos (Keeling) Islands
Colombia
Comoros
Cook Islands
Costa Rica
Croatia (Local Name: Hrvatska)
Curacao
Cyprus
Czech Republic
Democratic Republic of the Congo
Djibouti
Dominica
Dominican Republic
East Timor
Ecuador
Egypt
El Salvador
Equatorial Guinea
Eritrea
Estonia
Ethiopia
Falkland Islands (Malvinas)
Faroe Islands
Fiji
Finland
France
French Guiana
French Polynesia
French Southern Territories
Gabon
Gambia
Georgia
Germany
Ghana
Gibraltar
Greece
Greenland
Grenada
Guadeloupe
Guam
Guatemala
Guernsey
Guinea
Guinea-Bissau
Guyana
Haiti
Heard And McDonald Islands
Honduras
Hong Kong
Hungary
Iceland
Indonesia
Iraq
Ireland
Isle of Man
Israel
Italy
Jamaica
Jersey
Jordan
Kazakhstan
Kenya
Kiribati
Korea, Republic Of
Kosovo
Kuwait
Kyrgyzstan
Lao People's Democratic Republic
Latvia
Lebanon
Lesotho
Liberia
Liechtenstein
Lithuania
Luxembourg
Macau
Macedonia
Madagascar
Malawi
Malaysia
Maldives
Mali
Malta
Marshall Islands
Martinique
Mauritania
Mauritius
Mayotte
Mexico
Micronesia, Federated States Of
Moldova, Republic Of
Monaco
Mongolia
Montenegro
Montserrat
Morocco
Mozambique
Myanmar
Namibia
Nauru
Nepal
Netherlands Antilles
New Caledonia
New Zealand
Nicaragua
Niger
Nigeria
Niue
Norfolk Island
Northern Mariana Islands
Oman
Pakistan
Palau
Palestine
Panama
Papua New Guinea
Paraguay
Peru
Philippines
Pitcairn
Poland
Portugal
Puerto Rico
Qatar
Reunion
Romania
Russian Federation
Rwanda
Saint Bartholemy
Saint Kitts And Nevis
Saint Lucia
Saint Martin
Saint Vincent And The Grenadines
Samoa
San Marino
Sao Tome And Principe
Saudi Arabia
Senegal
Serbia
Seychelles
Sierra Leone
Sint Maarten
Slovakia
Slovenia
Solomon Islands
South Africa
South Georgia and the South Sandwich Islands
South Sudan
Sri Lanka
St. Helena
St. Pierre And Miquelon
Suriname
Svalbard And Jan Mayen Islands
Swaziland
Sweden
Switzerland
Taiwan
Tajikistan
Tanzania
Thailand
Togo
Tokelau
Tonga
Trinidad And Tobago
Tunisia
Turkey
Turkmenistan
Turks And Caicos Islands
Tuvalu
Uganda
Ukraine
United Arab Emirates
United States Minor Outlying Islands
Uruguay
Uzbekistan
Vanuatu
Vatican City
Venezuela
Vietnam
Virgin Islands (British)
Virgin Islands (U.S.)
Wallis And Futuna Islands
Western Sahara
Yemen
Yugoslavia
Zambia
Zimbabwe

By providing this information, you agree to the processing of your personal data by SANS as described in our Privacy Policy.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
  • © 2023 SANS™ Institute
  • Privacy Policy
  • Terms and Conditions
  • Do Not Sell/Share My Personal Information
  • Contact
  • Careers
  • Twitter
  • Facebook
  • Youtube
  • LinkedIn