From ISDN to AI - Two Veterans on How Defence in Depth Has Changed

Defence in depth has evolved every time the technology landscape has shifted. The internet, virtualisation, cloud, SaaS. AI is the next shift, and the old model isn't keeping up.Welcome to Razorwire, the podcast where we share our take on the world of cybersecurity with direct, practical advice for professionals and business owners alike. I'm Jim and in this episode, I'm joined once again by Martin Voelk, co-founder of SpartanX and an ethical hacker with nearly 26 years in cybersecurity.Every major technology shift has forced security teams to rethink how they protect their organisations. The internet moved data outside the building. Virtualisation and cloud meant infrastructure was no longer yours to control. Each time, defence in depth had to evolve. AI is the latest shift, and it may be the one that breaks the model entirely.We trace the journey from on-prem data centres and ISDN routers through to a world where AI agents act autonomously, supply chains are built on unverified code and the offensive side of AI is outpacing the defensive side at a rate security teams can't match. They get into why every AI agent needs its own identity, why shadow AI is a problem most organisations haven't begun to address and why the only realistic answer to AI-powered attacks is AI-powered defence.Three key talking points:Defence in depth has always evolved, but this time it's different:Every previous technology shift gave security teams time to catch up. AI isn't offering that. The pace of change is faster than most organisations can respond to, and the defensive tooling hasn't kept pace with what the offensive side can already do.AI agents need to be treated like people:Every AI agent needs its own identity, authentication and authorisation policies. Without that, a compromised agent can act under a human user's name with no way to tell the difference. The legal and forensic implications are enormous and largely unsolved.The offensive side is winning:AI is finding vulnerabilities faster than teams can fix them. Alert volumes are overwhelming SOCs, attackers are using AI-generated noise to mask real attacks and human in the loop is becoming unworkable at scale. The only realistic counter is defensive AI, but it isn't mature yet.Defence in depth has survived every technology shift so far. AI is testing it in ways we haven't seen before. If you're responsible for securing an organisation that's adopting AI, this is the conversation to listen to.On why security teams are always one step behind:"We don't have the ability to figure out what's going on until it's already happened. We don't have that technology yet."James ReesListen to this episode on your favourite podcasting platform: https://razorwire.captivate.fm/listenIn this episode, we covered the following topics:The Evolution of Defence in DepthFrom ISDN and on-prem data centres to cloud and SaaS, we trace how defence in depth has evolved with every major technology shift.Why AI Is DifferentPrevious shifts gave security teams time to adapt. We discuss why AI isn't offering that luxury.Supply Chain Risk and Unverified CodeOpen source code from GitHub, AI skills downloaded from the web, integrations nobody has reviewed. Discover why the modern supply chain is built on foundations most organisations haven't verified.Third Party Risk Management Is BrokenAI fills in vendor questionnaires and AI reviews the answers. We get into why the current TPRM process is fundamentally flawed.Shadow AILearn why unapproved AI usage is one of the hardest risks to detect and why most organisations have no way of monitoring it.Continuous AuthenticationSingle sign-on isn't enough anymore. We discuss why continuous authentication is becoming essential in environments where AI agents operate alongside human users.AI Agent Identity and AccountabilityFind out why every AI agent needs its own identity and access controls, and what happens when a compromised agent acts under a human user's name.Alert Fatigue as an Attack VectorFlooding a SOC with noise to mask a real attack isn't new, but AI makes it possible at a scale that's almost impossible to manage.Prompt Injection via Log FilesFind out how a prompt injection hidden in a standard HTTP header was used to trick a summarisation agent into exfiltrating data.The Case for Defensive AIOffensive AI is outpacing the defensive side. We discuss why AI-powered defence is the only realistic answer and why it isn't mature yet.Resources Mentioned SpartanXMartin Voelk - LinkedInKali LinuxDockerOllamaHugging FaceDeepSeekCrowdStrikeGitHubConnect with your host James ReesHello, I am James Rees, the host of the Razorwire podcast. This podcast brings you insights from leading cyber security professionals who dedicate their careers to making a hacker’s life that much more difficult.Our guests bring you experience and expertise from a range of disciplines and from different career stages. We give you various viewpoints for improving your cyber security – from seasoned professionals with years of experience, triumphs and lessons learned under their belt, to those in relatively early stages of their careers offering fresh eyes and new insights.With new episodes every other Wednesday, Razorwire is a podcast for cyber security enthusiasts and professionals providing insights, news and fresh ideas on protecting your organisation from hackers.For more information about us or if you have any questions you would like us to discuss email [email protected] you need consultation, visit www.razorthorn.com, We give our clients a personalised, integrated approach to information security, driven by our belief in quality and discretion.LinkedIn: Razorthorn SecurityYouTube: Razorthorn SecurityTikTok: Razorwire PodcastInstagram: Razorwire PodcastTwitter: @RazorThornLTDWebsite: www.razorthorn.comAll rights reserved. © Razorthorn Security LTD 2025