What is vulnerability prioritization?
Vulnerability prioritization is the practice of assessing and ranking identified security vulnerabilities based on critical factors such as severity, potential impact, exploitability, and business context. This ranking helps security experts and executives focus remediation efforts on the most critical vulnerabilities.
Between January and June 2024, more than 20,000 vulnerabilities were published. It sounds overwhelming, but vulnerability prioritization techniques help you approach cloud vulnerabilities effectively.
When you prioritize vulnerabilities, you tackle threats in order of criticality, addressing those that pose the greatest risk to your organization first. Strategic prioritization makes better use of your limited resources. It also helps you comply with regulations that require you to mitigate identified vulnerabilities promptly. Let’s take a closer look.
AWS Vulnerability Management Best Practices [Cheat Sheet]
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Cloud-specific considerations for prioritization
The advent of cloud computing introduced certain challenges to prioritization, especially due to transient resources, which can spin up and down rapidly. Keep these considerations in mind when implementing vulnerability prioritization:
The shared responsibility model
Security responsibilities are shared between the cloud service provider (CSP) and the customer. The CSP handles infrastructure security while the customer handles data and app security. Understanding the shared responsibility model will help you understand the vulnerabilities that fall under your control.
The ephemeral nature of cloud resources
Cloud resources (like containers, serverless functions, and auto-scaling instances) are often short-lived, created dynamically and destroyed on demand. Tracking vulnerabilities in such dynamic environments can be challenging because traditional static scanning methods may miss transient instances.
Increased attack surface
Many cloud services are accessible via the public internet, making them potential targets for attackers. Misconfigured S3 buckets, unencrypted storage services, exposed APIs, and open ports are frequent issues in cloud environments. Their interconnected nature increases the complexity of securing each communication point and raises the risk of lateral movement within the network.
The shared responsibility model, the ephemeral nature of cloud resources, and an increased attack surface need to be addressed in accordance with certain frameworks and benchmarks. We’ll explore these frameworks below so that you can design your vulnerability management process to meet the frameworks’ guidelines.
Vulnerability prioritization frameworks
1. Common Vulnerability Scoring System (CVSS)
CVSS is a standardized framework for assessing the severity of security vulnerabilities. It adds consistency to the manner with which high-risk vulnerabilities are rated based on impact and urgency. CVSS scores are applied to vulnerabilities so you can prioritize cloud risks in structured ways. Three metric groups contribute to the overall CVSS risk score: Base, Temporal, and Environmental Metrics. They represent the characteristics of vulnerabilities based on their constancy, transiency, and location, respectively.
CSPs often integrate CVSS into their security controls to optimize risk-based vulnerability prioritization.
2. Exploit Prediction Scoring System (EPSS)
EPSS is a framework designed by FIRST that provides a probabilistic assessment of exploitation risk. The prediction estimates the likelihood that a given vulnerability will be exploited over the next thirty days.
Unlike CVSS, EPSS helps you to prioritize vulnerabilities on their exploitability rather than their severity. For more comprehensive coverage, many organizations integrate EPSS with CVSS to add its probabilistic layer to CVSS's severity scores.
3. CSP frameworks
Cloud service providers offer frameworks to help their customers design secure cloud environments:
AWS Well-Architected Framework: The AWS framework is composed of multiple pillars, with the security pillar focusing on protecting systems and assets. It contains guidelines for managing identities, permissions, and access controls, as well as offering best practices for logging, monitoring, and intrusion detection.
Azure Security Benchmark (ASB): Microsoft’s framework provides recommendations for protecting network traffic in Azure and best practices for managing identities and access. The ASB provides guidelines for securing data at rest and in transit and strategies for detecting, responding to, and recovering from security incidents.
Google Cloud’s enterprise foundations blueprint: Google’s framework provides a prescriptive guide for managing user and service accounts and associated permissions. The enterprise foundations blueprint (previously known as the security foundations blueprint) outlines best practices for data encryption and secure storage, as well as recommendations for securing network communications.
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Essential contexts for cloud vulnerability prioritization
1. Asset criticality
Because financial systems and customer data repositories manage sensitive data like personal identifiable information, financial data, and intellectual property, they’re examples of highly critical assets. Categorizing your assets helps you prioritize vulnerabilities that could compromise your most significant data or functions. Common asset classifications are public-facing resources, internal systems, and regulatory-bound assets (e.g., systems handling credit card information subject to PCI DSS or healthcare data subject to HIPAA rules).
2. Environment type
Vulnerabilities affecting public-facing resources and assets in the demilitarized zone (DMZ) are prioritized due to their higher exposure and attack surface. In IaaS, PaaS, and SaaS models, focus on and prioritize resources under your domain.
Some regulatory requirements vary by region, so you should prioritize vulnerabilities based on compliance obligations in different geographic locations, such as GDPR for the European Union.
3. Operations dependencies
Critical chain dependencies can elevate the priority of even minor vulnerabilities, such as an unprotected central authentication service. These vulnerabilities are prioritized based on their immediate impact and their potential cascading effects on operations and services.
4. Business impacts
Exploited vulnerabilities can disrupt business operations and lead to financial losses. Vulnerability in core business functions such as ERP systems, payment processing platforms, and CRM systems merit the highest priority. And as we’ve seen, assets that are governed by requirements like GDPR, HIPAA, and PCI DSS should be prioritized because noncompliance can result in heavy fines and legal consequences.
5. Incident history
Take hints from previous security incidents and breaches and factor in recurring patterns when prioritizing current vulnerabilities. It’s also a good idea to evaluate the effectiveness of past remediation actions to refine prioritization strategies.
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Vulnerability prioritization strategies
1. Integration of frameworks with automated tools
Adopt security tools that incorporate frameworks to automate the scoring and prioritization of vulnerabilities. Automation ensures consistent assessment of vulnerabilities based on standardized criteria. Using the CSP frameworks explained above enhances the vulnerability prioritization process by aligning with the best practices tailored to the specific cloud environments.
2. Risk-based prioritization
Evaluate financial, operational, and reputational impacts by prioritizing vulnerabilities that could lead to business disruptions or regulatory backlash. Focus on high-value assets and systems, like financial systems, customer databases, and core business applications.
3. Combining multiple frameworks
Combining different frameworks, such as CVSS, EPSS, CSP-specific frameworks, provides you with multiple metrics and perspectives to achieve a deep understanding of vulnerability risk and priority. This multi-framework approach ensures that diverse risk factors and contexts are considered. It also reduces the likelihood of oversight or misprioritization by cross-referencing different assessment criteria.
4. Embracing DevSecOps
Integrate security checks within the CI/CD pipeline to catch vulnerabilities early in the development cycle. The security tool you choose should consistently and automatically scan code, dependencies, and configurations for vulnerabilities during development and deployment, which helps you identify and mitigate vulnerabilities before they reach production.
5. Threat intelligence
Use real-time threat intelligence tools to identify vulnerabilities actively exploited in the wild. The solution you select should leverage data from global threat repositories such as the CISA’s KEV to contextualize vulnerabilities, empowering you to prioritize vulnerabilities based on real-world threat data.
6. Zero-trust model & micro-segmentation
Adopt zero-trust principles so that every access request is verified regardless of its origin. Because the zero-trust model forces continuous verification, it inherently minimizes risk.
Take security one step further by dividing your cloud environment into smaller segments. By isolating workloads and network segments, you can target vulnerabilities within each segment.
7. Regular updates and adaptation
Regularly update and adapt vulnerability prioritization frameworks to reflect the ever-changing threat landscape. Utilize feedback from incident responses and vulnerability assessments to refine prioritization criteria.
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Key questions to ask yourself
This section is an inventory of preparatory questions you should ask yourself whenever your security team identifies a vulnerability.
1. What is the severity level of the vulnerability?
Utilize vulnerability scoring systems like CVSS to rate the severity. Scoring systems help you assess how much damage the vulnerability could cause.
2. What is the likelihood of this vulnerability being exploited?
Use EPSS to assess the likelihood of exploitation of the vulnerability so that you can prioritize accordingly.
3. Which areas of your cloud infrastructure are likely to be affected by the vulnerability?
Identify the cloud assets and resources that are vulnerable; consider the extent of the impact if affected and whether it affects sensitive data.
4. How does this vulnerability affect business operations?
Evaluate how downtime or data breaches could affect productivity, customer trust, and revenue.
5. What compliance requirements could be affected?
Review relevant regulatory standards your organization must adhere to, such as GDPR, HIPAA, and PCI DSS, to understand the implications of the vulnerability in terms of compliance violations.
6. Are remediation steps and mechanisms available?
Check if there are patches available and how feasible it is to deploy them.
7. How will prioritizing this vulnerability align with our overall security strategy?
Ensure that addressing the vulnerability fits within your broader security goals and vulnerability management framework.
Key features to look for in vulnerability prioritization tools
| Feature | Capabilities |
|---|---|
| Risk-based prioritization |
|
| Agentless, continuous scanning |
|
| Deep contextual assessments across technologies |
|
| Automated prioritization |
|
| Visualized reporting |
|
| Comprehensive vulnerability catalog |
|
| Integrations with existing security tools |
|
| Compliance features |
|
Prioritization in action: A simplified cloud scenario
Imagine you're the CISO of a rapidly growing fintech company that has recently migrated most of its infrastructure to a multi-cloud environment, utilizing services from both AWS and Azure. Your company's critical web application, which handles sensitive customer financial data, is distributed across this infrastructure. Your security team has just completed a comprehensive vulnerability scan, revealing multiple issues across your cloud environment.
Step 1: Discovery and inventory
Your security team conducts a thorough scan using cloud-native security tools, identifying:
A misconfigured S3 bucket in AWS containing customer PII
Unpatched software vulnerabilities in several EC2 instances
Exposed API keys in Azure Key Vault
Overly permissive IAM roles in both AWS and Azure
The scan generates a list of over 1,000 vulnerabilities, initially ranked by CVSS scores.
Step 2: Contextual risk assessment
The team assesses each vulnerability's contextual risk, considering:
Data sensitivity: The misconfigured S3 bucket is flagged as high risk due to the presence of customer PII.
Asset criticality: EC2 instances running core financial processing are prioritized.
Potential business impact: Exposed API keys could lead to unauthorized access and potential data breaches.
Step 3: Threat intelligence integration
By integrating threat intelligence feeds, the team discovers:
The unpatched software vulnerability is being actively exploited by a known threat actor targeting financial institutions.
Recent reports of data breaches caused by misconfigured cloud storage buckets in the fintech sector.
This intelligence elevates the priority of these vulnerabilities.
Step 4: Attack path analysis
Using attack-path visualization tools, the team identifies:
The exposed API keys could be used to move laterally within the cloud infrastructure, potentially compromising both AWS and Azure resources.
Overly permissive IAM roles could allow an attacker to escalate privileges and access sensitive data across multiple cloud services.
This analysis highlights the need to address these issues to prevent potential lateral movement and privilege escalation.
Step 5: Prioritization based on business impact
Collaborating with business stakeholders, the security team prioritizes vulnerabilities that could lead to:
Significant data breaches (misconfigured S3 bucket, exposed API keys)
Service disruptions (unpatched critical vulnerabilities in core financial processing EC2 instances)
Compliance violations (overly permissive IAM roles)
Step 6: Remediation and mitigation
Based on this prioritization, the team:
Immediately secures the misconfigured S3 bucket and implements stricter access controls.
Rotates all exposed API keys and implements a secrets management solution across both cloud environments.
Patches the vulnerable software on critical EC2 instances, scheduling updates for less critical systems.
Applies the principle of least privilege to IAM roles in both AWS and Azure, reducing unnecessary permissions.
Step 7: Continuous monitoring and re-evaluation
The team implements the following:
Continuous security posture management tools to detect new vulnerabilities or misconfigurations in real time
Regular penetration testing to identify potential attack paths across the multi-cloud environment
Periodic re-evaluation of prioritization criteria to align with evolving business needs and the changing threat landscape
By adopting this structured, context-aware approach to vulnerability prioritization, the fintech company effectively reduces its attack surface across its multi-cloud environment. This method ensures that limited security resources are focused on addressing the most critical risks, significantly enhancing the organization's overall security posture in a complex cloud ecosystem.
Wiz's agentless approach to cloud-native vulnerability management
Prioritize critical vulnerabilities based on business impact with Wiz’s agentless Vulnerability Management solution.
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How Wiz can help
You don’t have to address the sheer volume of cloud vulnerabilities alone. A cutting-edge tool like Wiz ensures that your organization focuses its resources on the most critical issues first.
Wiz analyzes your entire cloud environment to identify which resources are vulnerable and then ranks their severity and exploitability. Our all-in-one platform scans your VMs, containers, serverless functions, and more to both find vulnerabilities and provide contextual insights. By correlating asset configurations, network posture, data sensitivity, and existing vulnerabilities, Wiz makes prioritization possible at a glance.
And because complete coverage is essential, Wiz reports and alerts on public-facing resources, limited-public facing resources, and VMs and containers accessible from other subscriptions. Better yet? Our agentless approach to cloud-native vulnerability management helps you deploy very quickly.
Identify and Prioritize Vulnerabilities
Wiz analyzes your entire cloud environment to find vulnerable resources, making prioritization possible at a glance.
