> For the complete documentation index, see [llms.txt](https://docs.hyperdbg.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.hyperdbg.org/readme.md). # HyperDbg A hypervisor-assisted debugger designed for analyzing, fuzzing and reversing ## What is it? HyperDbg debugger is an open-source, user-mode, and kernel-mode debugger focusing on using hardware technologies to provide new features to the debuggers’ world. ![](https://1255335821-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-M2wWz6ePF27bvsJcWed%2Fuploads%2Fgit-blob-c678e1f7b33af09a0f83f8489e12222db4d15189%2FArtboard%202.png?alt=media) It is designed on top of Windows by virtualizing an already running system using Intel VT-x and Intel PT. This debugger aims not to use any APIs and software debugging mechanisms, but instead, it uses Second Layer Page Table (a.k.a. Extended Page Table or EPT) extensively to monitor both kernel and user executions. HyperDbg comes with features like hidden hooks, which is as fast as old inline hooks also stealth. It mimics hardware debug registers for (read & write) to a specific location, but this time entirely invisible for both Windows kernel and the programs, and of course without any limitation in size or count! Using TLB-splitting, and having features such as measuring code coverage and monitoring all mov(s) to/from memory by a function, makes HyperDbg a unique debugger. Although it has novel features, HyperDbg tries to be as stealthy as possible. It doesn’t use any debugging APIs to debug Windows or any application, so classic anti-debugging methods won’t detect it. Also, it resists the exploitation of time delta methods (e.g., RDTSC/RDTSCP) to detect hypervisors' presence, therefore making it much harder for applications, packers, protectors, malware, anti-cheat engines, etc. to discover the debugger. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.hyperdbg.org/readme.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.