IDA is a programmable, interactive, multi-processor disassembler combined with a local and remote debugger and augmented by a complete plugin programming environment.
IDA is in many ways unique. Its interactivity allows you to improve disassemblies in real time. Its multi-processor support is unmatched. Yet, two of our technologies are truly unique, have never been implemented under any form in any real-life disassemblers and, more importantly, are incredible time savers.
As a disassembler, IDA explores binary programs, for which source code isn't always available, to create maps of their execution. The real interest of a disassembler is that it shows the instructions that are actually executed by the processor in a symbolic representation called assembly language.
If the friendly screen saver you have just installed is spying on your e-banking session or logging your e-mails, a disassembler can reveal it. However, assembly language is hard to make sense of.
But, in real life, things aren't always simple. Hostile code usually does not cooperate with the analyst. Viruses, worms and trojans are often armoured and obfuscated. More powerful tools are required.
The debugger in IDA complements the static analysis capabilities of the disassembler: by allowing to single step through the code being investigated, the debugger often bypasses the obfuscation and helps obtain data that the more powerful static disassembler will be able to process in depth.
IDA can be used as a local and as a remote debugger on the 80x86 (typically Windows/Linux) and the ARM plaform (typically Windows CE PDAs). Remote debuggers are very useful when one wants to safely dissect potentially harmful programs.