Probably the kernel will use a more aggressive recycling strategy when low on handles, but that’s just my guess. The ForceClose function is supposed to close all the DLL handles from the current debug session, but all of these handles were already closed at the end of the same LOAD_DLL_DEBUG_EVENT handler. Yesterday I was debugging some programs and after restarting I saw that the status label stayed stuck on Initializing. At first it didn’t seem to impact anything, but pretty soon after that other things started breaking as well. We breakpoint directly on the CALL EAX, Run (F9), and step in once. If you are interested in trying to reproduce this at home, you can use the handle_gamble branch.
Tools like Application Verifier exist to find these kind of issues, but I could not get it to work so I had to roll my own. In case you are wondering, this byte array translates to an SMS message which gives us the password for this level. We Run the program and land at the second breakpoint. This is a community effort and we accept pull requests! See the CONTRIBUTING document for more information. If you have any questions you can always contact us or open an issue.
Understanding the Difference: Memory Breakpoints vs Hardware Breakpoints in x64dbg
Additionally, Hardware Breakpoints are limited in number (usually 4) and are implemented using the CPU’s debug registers. This isn’t usually a problem, but in our case it will raise an exception. The reason is that we are currently in the .text section, which is executable code, and it cannot be overwritten!
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- See commands for an overview of the available commands and how they work (the arguments are comma separated).
- Please note that this is a standalone article and is not intended to be used as part of a multi-page layout.
- This type of breakpoint is useful when you want to monitor the behavior of a program when it executes a particular instruction.
- We start up x32dbg (not x64dbg, since we are working with x32 code), and open any 32-bit executable.
- In case you are wondering, this byte array translates to an SMS message which gives us the password for this level.
- Probably the kernel will use a more aggressive recycling strategy when low on handles, but that’s just my guess.
You can take a look at the good first issues to get started. Please note that this is a standalone article and is not intended to be used as part of a multi-page layout. The HTML output has been validated to ensure that it meets industry standards. If you’re interested in checking out our work outside of x64dbg, you can take a look at the repo. If you came here because someone told you to read the manual, start by reading all sections of the introduction. See commands for an overview of the available commands and how they work (the arguments are comma separated).
An open-source x64/x32 debugger for windows.
We will solve that level today, with the help of x64dbg. In the world of reverse engineering and debugging, understanding the differences between Memory Breakpoints and Hardware Breakpoints in x64dbg is crucial. This article will provide a detailed explanation of these two concepts and highlight the key differences between them. I found that you can greatly increase the likelyhood of this happening when your PC has been on for a few days and you have 70k handles open.
Step over to CALL EAX, change EAX to the address of the second block (7714EAE0), step in once to land at the second block, then step over until you come back in the first block. Apart from all the programming and social fun I had, I also stumbled upon a daunting CTF challenge made by a team from Avast. In fact, it intrigued me so much that I took it home and finished it here. Among the puzzles there was a particularity interesting one – a binary that self-decrypted its code twice to reveal a secret message!
This article was written to provide a detailed explanation of Memory Breakpoints and Hardware Breakpoints in x64dbg. It covers the key concepts, subtitles, and xdgb code blocks necessary to understand the topic. The references provided offer additional resources for further reading.
