When debugging tools are used, this would mean that we are in the code-tracing phase of our analysis. Debuggers are used to step in every instruction the program is supposed to do. In the process of debugging, actual interaction and changes in memory, disk, network, and devices can be identified:

• x86dbg: This is a Windows user-mode debugger. It is open source and can debug 32- and 64-bit programs. It is capable of accepting plugins written by users. The source code can be downloaded from https://github.com/x64dbg. The builds can be downloaded from https://x64dbg.com.
• IDA Pro: Paid versions of IDA Pro are capable of debugging using the same disassembly interface. It is very useful when you want to see a graphical view of decrypted code.

• OllyDebug: A popular Windows debugger, due to its portability and rich features. It can accommodate plugins written by its users, adding capabilities such as unpacking a loaded executable compressed file (by reaching the original entry point) and memory dumping. Ollydebug can be downloaded from http://www.ollydbg.de/.
• Immunity Debugger: The interface of this program looks like a highly improved version of OllyDebug. It has plugin support for Python and other tools. Immunity Debugger can be downloaded from Immunity, Inc.'s site at https://www.immunityinc.com/products/debugger/. Older versions can be found at https://github.com/kbandla/ImmunityDebugger/.
• Windbg: A debugger developed by Microsoft. The interface is quite plain, but can be configured to show every kind of information needed by a reverser. It is capable of being set up to remotely debug device drivers, software in the kernel levels, and even a whole Microsoft operating system.
• GDB: Also known as GNU Debugger, GDB is originally a debugger developed for Linux and a couple of other operating systems. It is capable of debugging not only low-level languages but also used for debugging high-level languages such as C, C++, and Java. GDB can also be used in Windows. GDB uses a command-line interface, but there are existing GUI programs that use GDB for a more informative look.
• Radare: Radare also has a debugger packaged along with it. It can also do remote debugging by using GDB remotely. Its interface is command line-based but has an integrated visual view. Its developers also made a better visual view using the browser. Basically, compared with GDB, Radare would be much preferred. It is also primarily built for Linux, but has compiled binaries on offer for Windows and macOS.