How Often Should You Scan for External Vulnerabilities? Best Practices for Agencies

Most agencies still ask the same question: "How often should we scan our clients' websites for external vulnerabilities?"

In reality, digital environments change faster than most teams expect. New integrations appear, plugins update, DNS records shift, SSL certificates expire, and forgotten ports become exposed overnight. A single overlooked change can create a serious risk long before a quarterly or annual scan spots it.

This guide explains how frequently agencies should perform external vulnerability scanning, why continuous monitoring is becoming the baseline, and how to build a repeatable, agency-friendly process that reduces risk without adding operational stress.

1. Why Scan External Assets Regularly?

External vulnerability scanning identifies risks across public-facing assets such as:

Domains and subdomains
Open ports and services
SSL or TLS configurations
DNS exposure
HTTP headers and misconfigurations
Outdated or vulnerable technologies
Forgotten dev environments
Third-party dependencies

These items change constantly, often outside the agency's control. A client updates a plugin, a hosting provider changes DNS routing, or a new marketing tool injects a script. Every change, no matter how small, impacts the external attack surface.

Regular scanning ensures you catch issues before attackers do.

2. What Is the Recommended Scanning Frequency for Agencies?

✓ Daily scans (ideal for agencies with many clients)

Daily external scans provide the strongest protection and immediately highlight:

Newly exposed ports
DNS changes
SSL expiration windows
Sudden version updates
Emerging CVEs

This frequency is recommended for agencies managing multiple client sites because it provides early warnings without requiring manual oversight.

✓ Weekly scans (minimum baseline for SMB websites)

Weekly scanning is the industry minimum for:

WordPress, Shopify, Wix, Webflow, and custom sites
Clients with regular content or plugin updates
Websites that handle user data

This cadence catches changes early while keeping noise manageable.

✓ Monthly scans (acceptable only for low-risk static sites)

Monthly scans work for:

Static brochure websites
Single-page websites
Rarely updated online assets

Attackers do not wait a month, so this should be reserved for the smallest or least active clients.

3. Best Practices for Agencies Managing Client Vulnerabilities

A. Automate the entire workflow

Manual checks are impossible to scale across 10, 50, or 100-plus client sites. Use a scanning platform that supports:

Scheduled daily or weekly scans
Automated reporting
Alerting when exposure changes
Centralised dashboards

Automation reduces workload and increases visibility.

B. Combine external scanning with internal plugin or theme monitoring

External scans catch publicly visible risks. Internal plugin, theme, or CMS checks reveal:

Outdated plugins
Vulnerable versions
Misconfigured security settings

The two approaches work together, and clients expect both.

C. Report only what matters

Agencies must avoid overwhelming clients with noise. Prioritise:

Critical and high-risk findings
Items requiring immediate action
Steps the client can understand

Clear reporting builds trust and increases retention.

D. Track historical exposure trends

Agencies gain significant value by showing:

How exposure changed over time
How many vulnerabilities were resolved
How quick responses improved security

Clients love visual progress because they clearly see the value.

4. What Triggers Should Lead to Immediate External Scans?

Even with scheduled scans, some events call for instant re-scanning:

Website redesign or rebuild
New plugins, themes, or integrations
DNS additions or migrations
SSL reinstall or update
New hosting provider
Launch of a marketing campaign with third-party scripts
Client reports an issue or suspicious behaviour
High-risk CVEs announced in the wild

These trigger events help you stay ahead of exposure shifts.

5. Continuous Scanning vs. Periodic Scanning

Periodic scanning (weekly or monthly)

Good for detecting issues after they appear
Lower cost but higher risk
Ideal for small sites or budget-sensitive clients

Continuous external scanning

Detects changes within hours
Minimises attack windows
Helps agencies stay compliant with clients requiring ongoing security visibility
Becomes a recurring revenue product

For agencies, continuous scanning becomes a differentiator, especially when packaged with ongoing services or retainers.

6. What Agencies Should Communicate to Clients

Clients understand security better when you explain that:

"Your attack surface changes constantly."
"We monitor exposure every day to ensure nothing slips through."
"External risks appear even when you do not change anything."
"This is part of delivering stable, reliable digital performance."

Security becomes part of the agency's value, not an optional upsell.

7. Recommended Scanning Setup for Agencies

A complete agency-grade setup includes:

Daily automated external vulnerability scans
Developer-level technical reports plus client-friendly executive reports
A clean dashboard for all client domains
Alerts when new risks appear
Links to a remediation service or helpdesk workflow
An optional premium tier for continuous monitoring

If you offer managed hosting or retainer services, this becomes a natural addition. It strengthens client retention, improves trust, and reduces emergencies.

Conclusion

External vulnerability scanning is no longer a quarterly or yearly task. For agencies, the modern standard is daily or weekly automated scans, supported by clear reporting and proactive communication.

A consistent cadence helps you:

Protect clients
Avoid emergencies
Create recurring revenue
Strengthen long-term relationships

If you are an agency looking to automate daily external vulnerability scans, consolidate all client domains in one dashboard, and deliver clean technical plus executive reports, FYND provides continuous monitoring built specifically for agencies.