How Often Should You Perform Vulnerability Scans?

Vulnerability scanning is an important part of any effective security program.  They help organizations identify weaknesses in their systems before attackers can exploit them, and they provide insight for managing risk over time.  While many organizations scan reactively—after a breach, during an audit, or when a vendor requires it—proactive and consistent scanning is key to maintaining a strong security posture.

Industry best practices recommend performing internal and external vulnerability scans at least quarterly.  However, many frameworks and compliance programs now suggest, or require, more frequent scanning depending on risk level, system exposure, and the sensitivity of data handled.  In many environments, monthly or even continuous scanning is becoming the norm.

Let’s do a quick walkthrough of the scanning requirements and expectations from some of the most widely used and well-known security and compliance frameworks we often get asked about.

Payment Card Industry Data Security Standard (PCI DSS)

PCI DSS compliance demands quarterly vulnerability scans with additional rules for validation and remediation:

• External vulnerability scans must be performed at least quarterly and after any significant network change.
• Internal scans are also required quarterly or after significant changes.
• External scans must be conducted by an Approved Scanning Vendor (ASV).
• External ASV scans require high-risk vulnerabilities to be remediated (or have compensating controls) to pass.  
• Internal scans must have all high-risk vulnerabilities remediated (or properly mitigated) to be considered compliant.
  
  

Health Insurance Portability and Accountability Act (HIPAA)

HIPAA’s Security Rule does not mandate a specific scanning frequency (unlike PCI DSS).  Instead, it requires covered entities and business associates to implement a risk management program addressing vulnerabilities.  While not explicitly listed, regular vulnerability scanning is considered a reasonable safeguard under the Security Rule.  Organizations must:

• Conduct regular technical evaluations (like scans) as part of ongoing risk analysis.
• Establish and maintain a process for identifying and remediating vulnerabilities in systems handling ePHI (Electronic Protected Health Information).
• Document risk decisions, including acceptance or mitigation of vulnerabilities.
  
  

Cybersecurity Maturity Model Certification (CMMC)

Scanning requirements vary depending on the CMMC level:

• Level 1: No explicit scanning requirement, but basic safeguarding is expected.
• Level 2: Requires at least quarterly internal and external scanning and remediation per NIST SP 800-171.
• Level 3: Calls for advanced, near-continuous monitoring and response aligned with NIST SP 800-172.

In practice, organizations pursuing Level 2 or higher certifications must scan critical systems monthly or even weekly depending on DoD contract requirements.

National Institute of Standards and Technology (NIST)

NIST guidance around scanning is largely defined in SP 800-53 Rev. 5, SP 800-171, and SP 800-172.  Key expectations include:

• Performing regular scans at intervals determined by risk assessments and system criticality, and conducting ad-hoc scans when new threats emerge.
• For systems handling CUI (SP 800-171), monthly scans are typical, with increased frequency for high-value assets.
• Critical systems (SP 800-172) require advanced monitoring and rapid remediation.

For most environments, monthly scanning is considered a reasonable baseline, with more frequent assessments for systems with high impact ratings.

Center for Internet Security (CIS) 

CIS gives practical guidance on vulnerability scanning in Controls 7.3 and 7.4. Here's what you’ll want to know:

• Automated scans (7.3) should run at least weekly across all systems, with frequency adjusted based on risk.  Internet-facing systems or those handling sensitive data might need daily scans, while systems with lower risk profiles could be scanned less frequently.
• Manual reviews (7.4) fill in the gaps - they're your best bet for catching complex vulnerabilities or business logic flaws that automated tools might miss, especially in high-value systems.

Bonus: These recommendations align closely with major frameworks like ISO 27001, SOC 2, and FedRAMP, and are widely adopted as baseline security practices by organizations of all sizes.

Building a Sustainable Scanning Practice

Maintaining consistent vulnerability scanning at the right frequency requires both technical and operational alignment.  Secure Ideas provides a range of services to support both the technical and operational sides of this process.  

Our services include internal and external vulnerability assessments, asset discovery, and web app assessments.  We also offer PCI DSS–compliant external scans through our partnership with an Approved Scanning Vendor (ASV).

Whether you're focused on compliance, day-to-day risk management, or just getting started with vulnerability scanning, these services can help you build a repeatable, effective process.  We're always happy to share our experience and approaches if you're looking to improve how your organization handles vulnerability management.