How often should you have a Penetration Test?

Most companies should do penetration testing at least once a year, but annual testing should be treated as a baseline, not a complete strategy. A company should also test after significant infrastructure changes, major application releases, cloud migrations, mergers, incidents, new internet-facing services or material changes to risk. Higher-risk systems may need more frequent testing, targeted retesting or continuous validation. A penetration test is only a snapshot in time, so the real value comes from what happens after testing: prioritised remediation, validated fixes, evidence packs and improvements to the wider security programme.

Annual penetration testing is the baseline, not the full answer.

Annual penetration testing is a sensible starting point for most organisations. It creates a consistent point of assurance, gives technical teams an external view of exploitable weaknesses, and provides evidence for boards, auditors, insurers, customers, and procurement teams.

A yearly penetration test can be a sensible baseline. It should not be mistaken for continuous assurance.

For stable environments with limited change, annual penetration testing may be enough for a defined scope. A mature organisation with controlled releases, strong vulnerability management, clear asset ownership and low external exposure may not need full-scope testing every quarter. The risk arises when annual testing becomes a comfort blanket for environments that are constantly changing.

Annual testing answers what was true on the day of testing. It does not prove the environment remains secure for the rest of the year. If the environment changes two weeks after the test, the report no longer reflects the new risk.

That matters because many of the weaknesses that lead to compromise do not exist for a full year before being discovered. They appear after a rushed firewall change, a new Microsoft 365 configuration, a supplier platform integration, a cloud migration, a forgotten test environment or an application release that did not receive enough security review.

These outputs can support audit and assurance conversations around ISO 27001, Cyber Essentials, Payment Card Industry Data Security Standard (PCI DSS) and System and Organisation Controls 2 (SOC 2). PCI DSS has a clearer testing cadence than many other assurance frameworks, with penetration testing expected at least annually and after a significant change in relevant environments.

ISO 27001 should be handled more carefully. Penetration testing can support risk assessment, technical vulnerability management, control validation and evidence gathering, but it should not be presented as a simple certificate requirement. ISO 27001 Annex A control 8.8 focuses on managing technical vulnerabilities through identification, assessment and mitigation, which makes penetration testing useful evidence where the scope and risk justify it.

For organisations deploying or governing artificial intelligence systems, ISO/IEC 42001 may also influence how security testing, risk treatment, lifecycle controls and evidence are documented. It should not be treated as creating a universal penetration testing frequency. The frequency still needs to follow risk, exposure, change and assurance requirements.

How often should a company do penetration testing?

Most companies should do penetration testing at least annually, and again after significant changes to systems, applications, infrastructure or risk. Higher-risk environments may need more frequent targeted testing, retesting or continuous validation.

Testing frequency should change when the business changes.

The right question is not only how often to test. It is what to test, when, and why.

A company with stable infrastructure and low change may need a different testing rhythm than a business that releases applications every month. The same logic applies to organisations moving workloads into cloud platforms, changing identity controls, adopting new payment systems, expanding remote access or integrating acquired businesses.

Testing should follow a material change, not just the calendar.

Additional penetration testing should be considered after new web applications, major application releases, cloud migrations, significant Microsoft 365 or Azure configuration changes, firewall changes, network redesigns, identity and access management changes, mergers and acquisitions, new remote access routes, supplier platform changes, payment processing changes, high-risk artificial intelligence systems, data-heavy platforms, security incidents and new customer assurance requirements.

The scope should match the change. A web application release does not always need the same tests as an internal infrastructure assessment. A Microsoft 365 security change may need configuration review and targeted testing rather than a broad external infrastructure test. A new payment environment may need work aligned to PCI DSS expectations. A suspected compromise may need incident response first, followed by targeted testing once containment and recovery are under control.

External infrastructure penetration testing assesses internet-facing systems, including exposed services, perimeter controls, remote access points and cloud-hosted assets. Internal infrastructure testing examines what an attacker or a malicious insider could do from within the network. Web application penetration testing focuses on application logic, authentication, authorisation, session management, input handling and data exposure. Mobile application testing brings device, application programming interface and storage risks into scope.

Cloud configuration testing should be considered when new cloud services, identity models, storage permissions or network controls are introduced. Wireless testing remains relevant in office networks, warehouses, guest access, operational sites, or shared buildings, where additional exposure exists. Social engineering testing can be useful when leadership needs evidence of how people, processes, and technology interact, though it requires careful scoping and clear internal governance.

Red team exercises are useful when an organisation needs to test its detection and response capabilities. They should not be used to avoid fixing known vulnerabilities. A red team exercise tests real-world attack paths, monitoring, escalation and response under more realistic conditions. It is more useful when the basics are already under control.

Tabletop exercises help test decisions, escalation and business continuity. They do not replace technical testing. A tabletop exercise can show whether leaders know what to do when a technical issue becomes a business incident, especially where ransomware, identity compromise, supplier failure, backup integrity or recovery timelines are involved.

When should a company do penetration testing more often?

A company should test more often after major system changes, cloud migrations, application releases, mergers, incidents, new remote access routes, changes to payment environments, or when critical systems are exposed to higher risk.

How often should web applications be penetration tested?

Web applications should usually be tested before launch, after major releases, after significant code or architecture changes, and at regular intervals once live. High-risk or frequently updated applications may need more frequent targeted testing.

The schedule only matters if remediation and follow-up are built in.

A company can test four times a year and still make little progress if findings are not owned, fixed and validated. Frequency without remediation creates activity, not assurance. It keeps the calendar busy and leaves the risk largely untouched.

A penetration test that does not lead to remediation is a report-writing exercise. A provider that only hands over a PDF has completed the test, but has not helped the organisation reduce risk.

This is where selecting a penetration testing provider matters. A credible penetration testing provider in the United Kingdom should do more than run tools, exploit weaknesses and send a technical report. The provider should explain findings in business language, separate genuine risk from theoretical exposure, prioritise remediation, identify owners and support evidence gathering.

Critical and high-risk findings should not sit in a backlog waiting for the next annual test. They need ownership, deadlines and validation. Retesting gives the organisation evidence that important fixes have worked.

Conosco’s approach is built around this follow-up model. Its penetration testing service is focused on actionable UK-based testing across cloud, network, and application environments, with remediation support rather than a disconnected technical handover. Conosco also states that remediation guidance is provided as standard, with retesting options for Critical and High issues where proof is needed.

The output should support technical teams, risk owners, the board and audit conversations. That means clear findings, business impact, technical evidence, remediation priority, accountable owners and confirmation of what changed after remediation.

Penetration testing follow-up should connect to vulnerability management. Repeated issues often indicate a broader control failure: weak patching, poor asset visibility, inconsistent configuration standards, insecure development practices, overly permissive access or limited monitoring. Treating each finding as an isolated ticket hides the pattern.

Microsoft 365 security, identity controls, managed Security Operations Centre (SOC) monitoring and incident response should also influence the cadence. A penetration test may reveal a weakness. A managed SOC should help detect suspicious behaviour linked to that weakness. Incident response planning should define what happens if exploitation occurs. Governance, risk, and compliance activities should record the decision, treatment plan, residual risk, and evidence.

Penetration testing can also expose weaknesses that affect business continuity and disaster recovery planning, especially where critical systems, identity controls, backups, remote access, third-party dependencies or recovery processes are involved. It does not fully test business continuity and disaster recovery. Technical findings should feed resilience planning where relevant, while tabletop exercises test decision-making, escalation, crisis communication and recovery assumptions.

Do critical findings need retesting?

Critical and high-risk findings should normally be retested after remediation. Retesting helps confirm that the fix has worked and provides the organisation with evidence for risk, audit, or assurance purposes.

FAQ

Is once a year enough for penetration testing?

Once a year may be enough for stable, lower-risk environments with limited change. It is not enough that systems change frequently, new internet-facing services are added, applications are released often, or assurance expectations require further testing.

Should penetration testing happen after major changes?

Yes. Penetration testing should occur after material changes, such as cloud migrations, major application releases, network redesigns, new remote access routes, identity changes, payment environment changes, or mergers and acquisitions.

How often should external infrastructure be penetration tested?

External infrastructure should normally be tested at least annually and after significant changes to internet-facing systems. Higher-risk environments may need more frequent targeted testing.

How often should web applications be penetration tested?

Web applications should be tested before launch, after major releases, after significant architecture or code changes, and at regular intervals once live. Frequently updated or high-risk applications need a tighter cadence.

Is retesting needed after remediation?

Retesting is strongly recommended for critical and high-risk findings. It confirms whether the fix worked and provides technical teams, risk owners, and auditors with evidence that remediation has been completed.

Is a red team exercise the same as a penetration test?

No. A penetration test usually assesses a defined scope for exploitable weaknesses. A red team exercise tests attack paths, detection, response and escalation across people, process and technology.

Can penetration testing support ISO 27001, Cyber Essentials, PCI DSS, SOC 2 or ISO/IEC 42001?

Yes, where the scope is relevant. Penetration testing can support audit, assurance, risk treatment and evidence conversations. It should not be described as automatically making an organisation compliant with those frameworks.

Conosco support for penetration testing frequency, remediation and follow-up

Conosco helps organisations set a penetration testing frequency that reflects risk, change and assurance requirements. That includes annual penetration testing, penetration testing after major changes, targeted retesting, remediation planning and evidence that fixes have worked.

For organisations comparing a penetration testing provider UK-wide, the difference should be clear. A PDF-only handover leaves internal teams to interpret, prioritise and provide remediation alone. Conosco supports the work after the test by connecting findings to vulnerability management, Microsoft 365 security, managed Security Operations Centre monitoring, incident response, business continuity and disaster recovery, and governance, risk and compliance, where relevant.

Penetration testing should leave the organisation with fewer unresolved risks, stronger evidence and a clearer testing cadence. Anything weaker is a snapshot without enough follow-through.