OllyDbg (named after its author, Oleh Yuschuk) is an x86 debugger that emphasizes binary code analysis, which is useful when source code is not available. It traces registers, 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.[1]

Logo OllyDbg.svg
Original author(s)Oleh Yuschuk
Developer(s)Oleh Yuschuk
Stable release
2.01 / 27 September 2013; 7 years ago (2013-09-27)
Written inC
Operating systemMicrosoft Windows
Size6.6 MiB
LicenseShareware (version 1.x)
Freeware (version 2.x)


The software is free of cost, but the shareware license of version 1.x requires users to register with the author.[2] In version 2.x, the registration requirement was dropped.[3] The source code can be purchased from the author.[4]

The disassembler part of OllyDbg is free software, released under the GNU General Public License.[5]

Reverse engineeringEdit

OllyDbg is often used for reverse engineering of programs.[6] 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.[7] It is also useful for programmers to ensure that their program is running as intended, and for malware analysis purposes.

Related softwareEdit


  1. ^ Yuschuk, Oleh. "OllyDbg 64".
  2. ^ Yuschuk, Oleh. "Download". Archived from the original on 27 May 2012.
  3. ^ Yuschuk, Oleh (27 September 2013), "(No) registration", OllyDbg 2.01 Brief Help (zip)
  4. ^ Yuschuk, Oleh (27 September 2013), "Support", OllyDbg 2.01 Brief Help (zip)
  5. ^ Yuschuk, Oleh. "80x86 Assembler and Disasssembler".
  6. ^ Eilam, Eldad (2005). Reversing: secrets of reverse engineering. Wiley. p. 118. ISBN 978-0-7645-7481-8.
  7. ^ Ferguson, Justin; Kaminsky, Dan (2008). Reverse engineering code with IDA Pro. Syngress. p. 130. ISBN 978-1-59749-237-9.

External linksEdit