# Pinpointing heap-related issues: OllyDbg2 off-by-one story

DevFeed: [Pinpointing heap-related issues: OllyDbg2 off-by-one story](<https://devfeed.tech/articles/pinpointing-heap-related-issues-ollydbg2-off-by-one-story-39690.md>)

Original publisher: [Read original article](<https://doar-e.github.io/blog/2013/09/09/pinpointing-heap-related-issues-ollydbg2-off-by-one-story/>)

Author: Axel "0vercl0k" Souchet

Published: 2013-09-09T16:53:00Z

Content type: tutorial

Language: en

Sources: [Diary of a reverse-engineer](<https://devfeed.tech/sources/diary-of-a-reverse-engineer.md>)

Topics: [debug](<https://devfeed.tech/topics/debug.md>), [bug](<https://devfeed.tech/topics/bug.md>), [Assembly](<https://devfeed.tech/topics/assembly.md>), [x86](<https://devfeed.tech/topics/x86.md>), [App](<https://devfeed.tech/topics/app.md>)

Tags: [assembly](<https://devfeed.tech/tags/assembly.md>), [breakpoint](<https://devfeed.tech/tags/breakpoint.md>), [bug](<https://devfeed.tech/tags/bug.md>), [crashes](<https://devfeed.tech/tags/crashes.md>), [debug](<https://devfeed.tech/tags/debug.md>), [debugger](<https://devfeed.tech/tags/debugger.md>), [debugging](<https://devfeed.tech/tags/debugging.md>), [heap](<https://devfeed.tech/tags/heap.md>), [reverse-engineering](<https://devfeed.tech/tags/reverse-engineering.md>), [x86](<https://devfeed.tech/tags/x86.md>)

## AI overview

A technical walkthrough of diagnosing an off-by-one heap-related crash in OllyDbg2. The article uses GFlags, PageHeap, and WinDbg to locate the fault and reverse-engineer the buggy code and a reproducible trigger.

## Source excerpt

Introduction Yesterday afternoon, I was peacefully coding some stuff you know but I couldn't make my code working. As usual, in those type of situations you fire up your debugger in order to understand what is going on under the hood. That was a bit weird, to give you a ...