Repay Your Security Debt

Security debt refers to outdated or unsupported technology that exposes your organisation to cyber risks. This includes systems that are end-of-life (EoL) or end-of-support (EoS)[1], which no longer receive updates or maintenance. Like financial debt, security debt grows more expensive over time and can hinder future operations. For instance, unresolved issues in aging systems may delay new projects or amplify vulnerabilities.

Security debt stems from limited time, resources, or expertise to address technical gaps—often due to budget constraints. It appears as software bugs, missing patches, outdated systems, or non-compliant architectures. Without clear priorities, managing this debt can feel overwhelming, but ignoring it carries significant cyber risks.

Why Security Debt Increases Cyber Risks

Outdated technology is a prime target for cyberattacks. Systems that are not patched or maintained often have known vulnerabilities, making it easier for attackers to exploit them. Numerous cyber incidents demonstrate how unaddressed security debt is a critical weak point, underscoring its importance in effective cyber risk management. One prominent example is the breach of Equifax, an American credit bureau in 2017, which was possible because the company did not follow through on its own patching cycles and left systems vulnerable.[2]

Understand Your Risk and Set Priorities

As a board member, grasping the scope of your organisation’s security debt is crucial. Your technology leaders should maintain a register of technical debt, of which security debt is a sub-category, specifically identifying entries with security implications. To make this register actionable, your organisation needs clear definitions of what constitutes technical debt and security debt.

 The register should include a risk assessment, cost estimates to address each item, and a mapping of dependencies between security debt and broader business initiatives. Collaboration between business and technology teams ensures the register remains focused and avoids turning into an overly ambitious wish list.

Develop a Strategy to Repay Security Debt

A structured repayment strategy is essential for mitigating risks tied to security debt. Consider these four steps:

1.     Repay Debt by Default

Integrate security debt repayment into all new project plans. Systems that are being touched in a new project should be reviewed for security debt and the debt be settled, as it reduces overall costs and prevents delays. A business plan for a new initiative should have a section on debt repayment as a default.

2.     Prevent Debt Accumulation

Allocate adequate time and resources in new digitisation efforts to avoid creating additional security debt. A shared commitment between business and technology teams to maintain up-to-date systems is key to this goal.

3.     Prioritise Investments in Security Debt

Include critical investments for addressing security debt in your technology budgets and long-term roadmaps to ensure it remains a priority.

4.     Track Technology Upkeep

Develop a metric, such as a “Technology Upkeep Index,” to measure progress in keeping systems current. This provides visibility into your organisation’s efforts and helps maintain accountability.

Effectively managing security debt requires a collaborative approach between business and technology leaders. As cyber threats continue to grow, board members play a pivotal role in advocating for proactive repayment strategies and – if that is not feasible - ensuring alternative measures are in place to mitigate risks. The UK National Cyber Security Centre provides excellent guidance on mitigating the risks of Obsolete Products[3]. Addressing security debt is not merely a technical issue—it’s an essential contribution to your organisation’s cyber resilience.

[1] SAP LeanIX, 2025: https://www.leanix.net/en/wiki/trm/what-is-end-of-life-vs-end-of-support

[2] Wikipedia, 2025, https://en.wikipedia.org/wiki/2017_Equifax_data_breach?utm_source=chatgpt.com

[3] NCSC, Obsolete Products, 2025, https://www.ncsc.gov.uk/collection/device-security-guidance/managing-deployed-devices/obsolete-products