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Category: AppSec

How to prevent Cloudflare Proxy Bypasses

First two search results for “blocking origin access directly” on Google showed me two misleading Cloudflare community threads, with wrong security assumption, which is why I decided to write this guide. [1] [2] The best and recommended solution is using Authenticated Origin Pulls with custom certs per domain, but as this is not trivial to set up I decided write about…

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Hacking the LEDA LUC2 Fireplace: Reading CAN Bus Data with ESP32 and ESPHome

Ever since I installed a LEDA LUC2 fireplace, I wanted deeper insights into how it operates — particularly pressure difference, exhaust temperature, and ventilation state. Unfortunately, the vendor doesn’t provide any integration options, and the only external interface is a mysterious RJ12 port on the controller. So I decided to reverse engineer it myself. In this post, I’ll walk you…

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We’ve Normalised AI. But Not Secure Code.

Reflections from BSides Canberra 2023 to the Securing Sage Summit 2025 Last month at the Securing Sage Summit, I watched Sonya M. from Snyk give a slick, fast-paced live demo using GitHub Copilot. It was exactly the kind of session that draws a crowd — showing how quickly AI can help generate code from natural language prompts. But then it…

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Is it just me – or is 2025 the year of scale?

Maybe it’s just the talks I’ve attended and articles I read. Maybe it’s just my rabbit hole that I went into. Or maybe… we’re all collectively realising the same thing. I hit a wall. At the end of 2024, I went all-in on automation. I built MVPs, tested capabilities, and made it my mission to influence others to do the…

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From mysql_real_escape_string() to AI Firewalls: Are We Repeating History with Prompt Injection?

In the early days of web development, PHP developers often relied on functions like mysql_escape_string() to sanitize user inputs. However, this approach was fraught with pitfalls. Misuse, incorrect character encoding handling, and a lack of awareness led to numerous vulnerabilities. To address these issues, mysql_real_escape_string() was introduced, which considered the current character set of the database connection, offering a more…

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Scaling AppSec in High-Velocity Engineering: My Take

Jason Chan’s article “Security for High Velocity Engineering” hit me hard. It captures a reality many of us in Product Security face: engineering teams move fast, and unless your security program evolves beyond one-off engagements and reactive fixes, you’ll constantly be playing catch-up. The Fragile Model: When 1:1 Investment Walks Out the Door When I started out as an AppSec…

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Hacking your not-so-smart doorbell – Home Assistant and Gemini AI

At DEFCON32, my colleague Andra Lezza and I presented a talk on building and securing LLM applications – particularly chatbots – drawing from our work at Sage. One of the highlights of our talk was a practical proof of concept: a smart home setup using Home-Assistant.io, which we showcased to demonstrate safety implications and security considerations of AI-integrated applications. In…

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AppSec Team Topologies Explained: Structure in Matrix Organisations

In a world where security needs to move as fast as software delivery, how we structure our AppSec (Application Security) teams is more critical than ever. The right team topology can make the difference between a well-secured application and a bottlenecked security process. Before looking in detail into these structures, let’s break down some essential team types that shape how…

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Rethinking Shift-Left: More Than Just Eliminating Vulnerabilities?

Over the past few years, the concept of “shift-left” has dominated software security. The idea seems intuitive – catch vulnerabilities as early as possible in the development process, allowing teams to remediate issues long before they ever reach production. But after a recent discussions, I started thinking more critically about what shift-left actually delivers and, more importantly, where it might…

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Relying solely on IP Allowlisting with Cloudflare is WRONG

The Misconception IP allowlisting involves configuring your origin server to accept connections only from specific IP addresses – in this case, Cloudflare’s IP ranges. The logic seems sound: by allowing only trusted IPs, you reduce the risk of unauthorized access. Unfortunately, this method overlooks several attack cases that can be exploited. My Observation Over the years, I’ve noticed numerous security…

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