OllyDbg is a 32-bit assembler level analysing debugger for Microsoft® Windows®. Emphasis on binary code analysis makes it particularly useful in cases where source is unavailable. OllyDbg is a shareware, but you can download and use it for free.
Special highlights are:
- Intuitive user interface, no cryptical commands
- Code analysis – traces registers, recognizes procedures, loops, API calls, switches, tables, constants and strings
- Directly loads and debugs DLLs
- Object file scanning – locates routines from object files and libraries
- Allows for user-defined labels, comments and function descriptions
- Understands debugging information in Borland® format
- Saves patches between sessions, writes them back to executable file and updates fixups
- Open architecture – many third-party plugins are available
- No installation – no trash in registry or system directories
- Debugs multithread applications
- Attaches to running programs
- Configurable disassembler, supports both MASM and IDEAL formats
- MMX, 3DNow! and SSE data types and instructions, including Athlon extensions
- Full UNICODE support
- Dynamically recognizes ASCII and UNICODE strings – also in Delphi format!
- Recognizes complex code constructs, like call to jump to procedure
- Decodes calls to more than 1900 standard API and 400 C functions
- Gives context-sensitive help on API functions from external help file
- Sets conditional, logging, memory and hardware breakpoints
- Traces program execution, logs arguments of known functions
- Shows fixups
- Dynamically traces stack frames
- Searches for imprecise commands and masked binary sequences
- Searches whole allocated memory
- Finds references to constant or address range
- Examines and modifies memory, sets breakpoints and pauses program on-the-fly
- Assembles commands into the shortest binary form
- Starts from the floppy disk
and much, much more!
