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OllyDbg

ollydbg.org

Free plan Windows
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Spec score 7.5 #17 of 27 in Debuggers

What it is

OllyDbg is a free 32-bit assembler-level debugger for Microsoft Windows, intended for binary analysis when source code is unavailable. It traces registers and identifies procedures, loops, API calls, switches, tables, constants, and strings. The debugger can load DLLs, attach to running programs, and handle multithreaded applications. Breakpoint types include conditional, logging, memory, and hardware breakpoints; execution tracing can log arguments for known functions. Patches can be retained between sessions, written back to executable files, and used to update fixups. An open architecture supports third-party plugins, and the maker provides a Plugin Development Kit with documented samples. Listed requirements include Windows 95, 98, NT 4.0, 2000, or higher; Win32s is unsupported. Development is frozen, and the 64-bit version is incomplete. Registration is free and requested for permanent or commercial use. The maker says original versions 1.00–1.10 do not communicate with other computers except for remote files specified by the user.

Spec sheet

Purpose
OllyDbg is a 32-bit assembler-level debugger for Microsoft Windows, intended for binary code analysis when source code is unavailable.Read 8 Oct 2026 · ollydbg.org
Privacy
For original versions 1.00–1.10, the maker says OllyDbg does not act as a network client or server or send data to another computer, except for remote files specified by the user.Read 8 Oct 2026 · ollydbg.org
Support
The FAQ says the author usually answers email questions within 1–3 days.Read 8 Oct 2026 · ollydbg.org
Analysis limit
The FAQ says OllyDbg cannot analyze only a selected piece of code because changes can affect analysis outside that selection.Read 8 Oct 2026 · ollydbg.org
Breakpoints and tracing
It supports conditional, logging, memory, and hardware breakpoints, and can trace execution while logging arguments of known functions.Read 8 Oct 2026 · ollydbg.org
Code analysis
It traces registers and recognizes procedures, loops, API calls, switches, tables, constants, and strings.Read 8 Oct 2026 · ollydbg.org
Compatibility
The maker lists Microsoft Windows 95, 98, NT 4.0, 2000, or higher as system requirements; OllyDbg does not work under Win32s.Read 8 Oct 2026 · ollydbg.org
Debugging
It can load and debug DLLs, attach to running programs, and debug multithreaded applications.Read 8 Oct 2026 · ollydbg.org
Development status
The maker says development is frozen and describes the 64-bit version as incomplete.Read 8 Oct 2026 · ollydbg.org
Patching
It saves patches between sessions, writes them back to executable files, and updates fixups.Read 8 Oct 2026 · ollydbg.org
Plugins
Its open architecture supports third-party plugins, and the maker provides a Plugin Development Kit with documented sample plugins.Read 8 Oct 2026 · ollydbg.org
Registration
The maker says registration is free, carries no financial or other obligations, and is requested for permanent or commercial use.Read 8 Oct 2026 · ollydbg.org
Security caveat
The maker warns that it cannot guarantee archives or third-party modifications are free from viruses or Trojan horses.Read 8 Oct 2026 · ollydbg.org

Plans and prices

OllyDbg Free Free to download and use · Registration is free and requested for permanent or commercial use Read 8 Oct 2026 · ollydbg.org

Every OllyDbg plan and price →

Strong points and limits

Strong points

  • Free to download and use
  • Conditional and hardware breakpoints
  • Can debug DLLs and multithreaded apps
  • Patches persist between sessions
  • Plugin architecture with development kit

Limits

  • 32-bit debugger
  • Development is frozen
  • 64-bit version is incomplete
  • Does not work under Win32s

Who it suits

OllyDbg suits Windows users analyzing 32-bit binaries without source code, including those needing breakpoints, tracing, patching, or plugins. Registration is relevant for permanent or commercial use.

Verdict

OllyDbg offers detailed 32-bit Windows binary debugging with tracing, breakpoints, patching, and extensibility. Its frozen development and incomplete 64-bit version define the main platform limits.

Where Specifiction places it

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