OllyDbg (named after its author, Oleh Yuschuk) was an
x86 debugger
A debugger or debugging tool is a computer program used to test and debug other programs (the "target" program). The main use of a debugger is to run the target program under controlled conditions that permit the programmer to track its executi ...
that emphasizes binary code analysis, which is useful when source code is not available. It traces
register
Register or registration may refer to:
Arts entertainment, and media Music
* Register (music), the relative "height" or range of a note, melody, part, instrument, etc.
* ''Register'', a 2017 album by Travis Miller
* Registration (organ), th ...
s, recognizes
procedures,
API calls,
switches,
tables,
constants and
strings, as well as locates routines from object files and libraries. It has a user friendly interface, and its functionality can be extended by third-party plugins. Version 1.10 is the final 1.x release. Version 2.0 was released in June 2010, and OllyDbg has been rewritten from the ground up in this release. Although the current version of OllyDbg cannot disassemble binaries compiled for 64-bit processors, a 64-bit version of the debugger has been promised.
License
The software is free of cost, but the shareware license of version 1.x requires users to register with the author. In version 2.x, the registration requirement was dropped. The source code can be purchased from the author.
The disassembler part of OllyDbg is free software, released under the
GNU General Public License
The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general ...
.
Reverse engineering
OllyDbg is often used for
reverse engineering
Reverse engineering (also known as backwards engineering or back engineering) is a process or method through which one attempts to understand through deductive reasoning how a previously made device, process, system, or piece of software accompli ...
of programs.
It is often used by crackers to
crack software made by other developers. For cracking and reverse engineering, it is often the primary tool because of its ease of use and availability; any 32-bit executable can be used by the debugger and edited in bitcode/assembly in realtime.
It is also useful for programmers to ensure that their program is running as intended, and for malware analysis purposes.
Related software
*
Interactive Disassembler
The Interactive Disassembler (IDA) is a disassembler for computer software which generates assembly language source code from machine-executable code. It supports a variety of executable formats for different processors and operating systems. I ...
(IDA Pro)
*
Radare2
*
Ghidra
*
Cheat Engine
Cheat Engine (CE) is a proprietary, source available freeware memory scanner/debugger created by Eric Heijnen ("Byte, Darke") for the Windows operating system. Cheat Engine is mostly used for cheating in computer games and is sometimes mo ...
*
Debuggers for reverse-engineering software
*
x64dbg
*
Syser Debugger
Syser Debugger by reversecode x32/x64 (reverse engineering & improvement)
References
{{reflist
External links
OllyDbgOllyDbg Plug-insPlug-ins and tools for OllyDbg
Debuggers
Disassemblers