https://gc0rp.github.io/Recent content on Ojas Gupta BlogHugoen-usFri, 08 May 2026 15:00:00 +1000https://gc0rp.github.io/posts/0ctfbabyheap/Fri, 08 May 2026 15:00:00 +1000https://gc0rp.github.io/posts/0ctfbabyheap/<h2 id="introduction">Introduction</h2> <p>I will demonstrate how the fast-bin attack works. The 0ctf&rsquo;s babyheap challenge will be used to showcase the attack. This CTF is using the glibc-2.23 library.</p> <p>For both of the files (0ctfbabyheap and libc-2.23.so) we will be dealing with PIE &amp; NX. NX can stop us from executing shellcode in certain memory frames. PIE enabled will allow ASLR to randomize the base addresses. This means we will need an infoleak in order to get a shell.</p>https://gc0rp.github.io/posts/hitcon-14-stkof/Thu, 19 Mar 2026 15:27:13 +1000https://gc0rp.github.io/posts/hitcon-14-stkof/<h2 id="introduction">Introduction</h2> <p>This writeup will walkthrough the solution for HITCON 14&rsquo;s Stkof problem. I demonstrate the solution by using the unsafe unlink technique and trigger the shell with onegadget.</p> <h2 id="the-unlink-process">The unlink process</h2> <p>The unsafe unlink is a heap exploitation technique that allows us to unlink a heap chunk and achieve an arbitrary write. An arbitrary write will then be used to modify function hooks which are used to call functions. In our post we will target the <code>malloc</code> call to trigger the shell then modify the address <code>strlen</code> to <code>puts</code> for an info leak.</p>https://gc0rp.github.io/posts/objects-in-disguise/Thu, 19 Jun 2025 15:00:00 +1000https://gc0rp.github.io/posts/objects-in-disguise/<h1 id="introduction">Introduction</h1> <p>In this article we will explore some ways V8 optimizes your Javascript code. I will share some of the knowledge I have learnt over the past few weeks reading blogs.</p> <p>Bonus Points!! if you&rsquo;re interested in using this knowledge to exploit web browsers (for educational purposes, obviously).</p> <h1 id="the-purpose-of-v8">The purpose of V8</h1> <p>As web applications become the new normal for many people around the globe. Google set out on a journey to make web browsers run applications as smoothly desktop applications. As a result of this, V8 was born.</p>https://gc0rp.github.io/posts/ret2-mission1/Sun, 15 Jun 2025 15:27:13 +1000https://gc0rp.github.io/posts/ret2-mission1/<h2 id="problem-description">Problem Description</h2> <p>Even as modern desktops and servers gain more mitigations and protections, somehow Internet Of Things devices lag way behind.</p> <p>Yet people have started introducing countless &ldquo;smart&rdquo; devices into their home and onto their network.</p> <p>It is time to hack into these toasters, refrigerators, thermostats, and lightbulbs.</p> <h2 id="initial-analysis-of-the-challenge">Initial Analysis of the Challenge</h2> <p>I noticed some interesting function names when the file was loaded into Binary Ninja that I thought I may end up using later.</p>