Vulnerability Management

Vulnerability management is the ongoing practice of identifying, assessing, prioritizing, and remediating security weaknesses across an organization's infrastructure, applications, and systems. It is a continuous cycle — not a one-time scan — that ensures known vulnerabilities are addressed before attackers exploit them.

The Vulnerability Management Lifecycle

1. Discovery — Identify all assets in the environment (servers, endpoints, applications, cloud resources)
2. Scanning — Run automated vulnerability scans to detect known weaknesses
3. Assessment — Evaluate each vulnerability's severity using scoring systems like CVSS
4. Prioritization — Rank vulnerabilities by risk, considering exploitability, asset criticality, and business context
5. Remediation — Apply patches, configuration changes, or compensating controls
6. Verification — Rescan to confirm vulnerabilities are resolved
7. Reporting — Track metrics and communicate status to stakeholders

Compliance Requirements

PCI DSS has the most prescriptive requirements. Requirement 6.3.3 mandates installation of critical security patches within one month. Requirement 11.3 requires quarterly internal and external vulnerability scans, with external scans conducted by an Approved Scanning Vendor (ASV).

ISO 27001 control A.8.8 addresses management of technical vulnerabilities. Organizations must establish a process for identifying and responding to technical vulnerabilities in a timely manner.

NIST CSF Protect function includes vulnerability management as a key subcategory, with specific guidance on vulnerability disclosure and remediation processes.

SOC 2 auditors evaluate whether the organization identifies and addresses vulnerabilities as part of its risk management and system operations processes.

Prioritization Strategies

Not every vulnerability requires immediate attention. Effective prioritization considers:

• CVSS score — Industry-standard severity rating
• Exploitability — Whether exploits exist in the wild
• Asset criticality — The importance of the affected system to business operations
• Exposure — Whether the vulnerable system is internet-facing or internal only
• Compensating controls — Whether other controls reduce the effective risk

Best Practices

Scan regularly. Weekly or continuous scanning for critical systems; monthly for lower-risk assets. Quarterly-only scanning is insufficient for most environments.

Patch promptly. Define SLAs for remediation based on severity — critical vulnerabilities within days, high within weeks, medium within a defined period.

Track metrics. Mean time to remediate, vulnerability aging, and scan coverage are key indicators of program effectiveness.