State-of-the-art binary code analysis tools
Let’s consider this snippet from decompilation of an x86 Windows binary: The same function is called twice with the same argument and the last one doesn’t seem to use the result of the GetComputerNameExW call. By switching to disassembly, we can see that eax is initialized before each call with a string address: However the decompiler does not […]
The Functions list is probably the most known and used part of IDA’s default desktop layout. It includes all detected functions in the current database and offers a quick way to find and navigate to any of them. However, the database consists not only of functions but also data items or instructions which are […]
Let’s say you found a promising-looking string in the binary, followed the cross reference to the function using it, then decompiled it to see how the string is used, only to see no signs of it in the pseudocode. What’s happening? In such situation it often helps to set up two synchronized disassembly<->pseudocode views and […]
As covered before, the action “Create struct from selection” can be used to quickly create structures from existing data items. However, Disassembly view not the only place where it can be used. For example, let’s imagine you’ve created a structure to represent some context used by the binary being analyzed: 00000000 Context […]
This is a guest entry written by Sergejs Harlamovs from IKARUS Security Software GmbH. His views and opinions are his own and not those of Hex-Rays. Any technical or maintenance issues regarding the code herein should be directed to the author. IdaClu: Finding clues without knowing what to seek IdaClu, as the name suggests, is about […]
In order to faithfully represent the behavior of the code and to conform to the rules of the C language, the decompiler may need to add casts in the pseudocode. A few examples: a variable has been detected to be unsigned but participates in a signed comparison: An argument being passed to a function does not match […]
In order to show the user only the most relevant code and hide the unnecessary clutter, the decompiler performs various optimizations before displaying the pseudocode. Some of these optimizations rely on various assumptions which are usually correct in well-behaved programs. However, in some situations they may be incorrect which may lead to wrong output, so […]
When working with the decompiler, you probably spend most of the time in the pseudocode view, since most interactive operations (e.g. renaming, retyping and commenting) can be done right there. IDA is usually smart enough to detect important changes during such actions and update the pseudocode as necessary. However, occasionally you may perform actions […]
When you need to change the prototype of a function in the decompiler, the standard way is to use the “Set item type…” action (shortcut Y). One case where you may need to do it is to add or remove arguments. Especially in embedded code or when decompiling variadic functions, the decompiler may deduce the argument […]
Firmware binaries often use raw binary file format without any metadata so they have to be loaded manually into IDA. You can do it interactively using the binary file loader, but if you have many files to disassemble it can quickly get boring. If you already know some information about the files you’re disassembling, […]