Last updated at Fri, 15 Dec 2023 17:18:47 GMT

That's right, the much anticipated and long awaited 0.4 release is finally here!

Just like divas arrive late at the gala, we took some more time than expected, but are now worthy of a triumphant entrance.

If you're not familiar with Cuckoo Sandbox, it's an open source solution for automating malware analysis.

What does that mean? Simply that you can throw any suspicious file at it and after a few seconds it will give you back detailed information on what that file does when executed inside an isolated environment. Most importantly, the power of Cuckoo relies on infinite customization and scripting possibilities, allowing you to shape it as you want and making it perform virtually any analysis task you might think of. In addition, it's powerful processing and customization modules will allow you to make your analysis consumable like no others.

When we started the Magnificent7 program we had an initial set of milestones that we were hoping to achieve in time for August. The good news is that not only have we met those goals, but we've also done much more!

If you already have some experience with Cuckoo, you will find this release to be significantly different from previous ones. Since the long-term plans that we had for the project did not meet the old structure and design, we decided to rewrite every single component from scratch with modularity, scalability and flexibility in mind.

We consider 0.4 to be an historical milestone in our project's history and the best release we have produced so far.

Following are some of the most noteworthy features we introduced:

  • Modules for performing custom post-analysis processing of the results and generating reports: being able to customize the interpretation of the results and the generation of reports in any format you want, you can easily integrate Cuckoo in any existing framework or environment you already have in place.
  • Default support for KVM and the ability to create new, or modify existing, Python modules that will instruct Cuckoo on how to interact with your virtualization solution of choice.
  • A signatures engine that you can use to identify and isolate any pattern or event of interest: contextualize the analysis results, quickly identify known malwares or look for particularly interesting events for you or your company.
  • Improved scripting capabilities, further customizing the sandbox to your analysis needs. You can now customize Cuckoo's analysis process to the best extent by simply writing Python modules that define how the sandbox should interact with the malware and the analysis environment.
  • Last but not least, we completely re-engineered our analysis core. This will significantly improve the quality of our analysis, giving much more detailed and explicative information about the malware you're analyzing.

So what you're waiting for? You can get it at:

There you can find links to downloads, documentation and everything you might need to get started.

I created Cuckoo more than two years ago and I've seen it grow from a small, hacky and unstable project to the largely used and community-driven malware analysis solution that it is now and will be in the future. This release is the result of a lot of hours of dedication and hard work of not just me, but some other individuals as well that I'd want you all to meet and thank properly...

Alessandro "jekil" Tanasi has always been a passive project advisor since the very beginning, but joined our forces last year actively improving and polishing our code base. This is what he had to say:

Developing Cuckoo is an amazing challenge. We have to deal with different technologies and we spend lot of efforts integrating them and combining them in a way that has to satisfy the needs of all our users, who come from very different backgrounds and branches of IT. All of this faithful to the principles of Open Source, which proved to be very difficult and troubling, having few resources, high competition and trying to be one of the best sandboxes around. And we have fun doing that.

Cuckoo is the result of our work and experiences on multiple topics: it's an effort of security research, malware analysis, development, testing. We deal with virtualization, Windows internals, rootkit technologies, storages and data mining and we have to keep up with the latest malware threats. Our users understand and appreciate our efforts, their feedback is the key of Cuckoo's success and we are looking forward to have a more community-driven development lifecycle in the near future. So stick with us and wait for what comes next...

As our latest addition to the team and as developer of the new analysis core, this is what Jurriaan "skier" Bremer had to say about the release:

For this release of Cuckoo Sandbox we have rewritten the analysis component from scratch, which introduces some nifty features, a much more solid execution and very detailed results.

Just like before we employ inline hooking as the core mechanism to track the execution of the malware, but not only does the new component install hooks for the libraries which are loaded during initialization of the process, we also place them on pre-defined functions located in libraries which are loaded at runtime. This is extremely useful for binaries which have been packed, because packers tend to resolve all libraries and function addresses at runtime. We also improved our logging system, our files dump, our injection and process follow logic and we are now tracing both native and Windows API functions.

All in all we have developed a new and stable component for Cuckoo Sandbox 0.4 with the flexibility to expand and improve even further in the future.

So now you're only left to go and try it!

I will be attending the BlackHat Briefings in the coming days, feel free to come visit me as I'll be hanging around the Rapid7 booth giving demos of the sandbox in the context of our participation to the Magnificent7 program.

Coming to a conclusion, I'd like to extend my gratitude also to Mark "rep" Schloesser, the Cuckoo ML community, The Honeynet Projec, the folks at The Shadowserver Foundation, Rapid7 for the extremely precious support and everyone using Cuckoo for making it become what it is today.

Follow us on Twitter @cuckoosandbox.