What is Cuckoo?

Cuckoo is an open source automated malware analysis system.

It’s used to automatically run and analyze files and collect comprehensive analysis results that outline what the malware does while running inside an isolated Windows operating system.

It can retrieve the following type of results:

  • Traces of win32 API calls performed by all processes spawned by the malware.
  • Files being created, deleted and downloaded by the malware during its execution.
  • Network traffic trace in PCAP format.
  • Screenshots of Windows desktop taken during the execution of the malware.
  • Traces of assembly instructions performed by the malware.

Some History

Cuckoo Sandbox started as a Google Summer of Code project in 2010 within The Honeynet Project. It was originally designed and developed by Claudio “nex” Guarnieri, who still mantains it and coordinates all efforts from joined developers and contributors.

After initial work during the summer 2010, the first beta release was published on Feb. 5th 2011, when Cuckoo was publicly announced and distributed for the first time.

In March 2011, Cuckoo has been selected again as a supported project during Google Summer of Code 2011 with The Honeynet Project, during which Dario Fernandes joined the project and extended its functionalities.

On November 2nd 2011 Cuckoo the release of its 0.2 version to the public as the first real stable release.

On late November 2011 Alessandro “jekil” Tanasi joined the team expanding Cuckoo’s processing and reporting functionalities.

On December 2011 Cuckoo v0.3 gets released and quickly hitting release 0.3.2 in early February.

In late January 2012 we opened Malwr.com, a free and public running Cuckoo Sandbox instance provided with a full fledged interface through which people can submit files to be analysed and get results back.

Use Cases

Cuckoo is designed to be used both as a standalone application as well as to be integrated in larger frameworks, thanks to its submission and processing automation capabilities.

It can be used to analyze:

  • Generic Windows executables
  • DLL files
  • PDF documents
  • Microsoft Office documents
  • URLs
  • PHP scripts
  • Almost everything else

Thanks to its scripting and customization capabilities there’s basically no limit to what you can achieve with Cuckoo, for example automating malware unpacking or automating the dump of configuration files and web-injects from banking trojans.

For more information on customizing Cuckoo, see the Customization chapter.


Cuckoo Sandbox consists of a central management software which handles sample execution and analysis.

Each analysis is launched in a fresh and isolated virtual machine. Cuckoo’s infrastructure is composed by an Host machine (the management software) and a number of Guest machines (virtual machines for analysis).

The Host runs the core component of the sandbox that manages the whole analysis and execution process, while the Guests are the isolated environments where the malwares get actually safely executed and analyzed.

The following picture explains Cuckoo’s architecture:


Although recommended setup is GNU/Linux (Ubuntu preferrably) as host and Windows XP Service Pack 3 as guest, Cuckoo proved to work smoothly also on Mac OS X as host and Windows Vista and Windows 7 as guests.

Obtaining Cuckoo

Cuckoo can be downloaded from the official website, where the stable and packaged releases are distributed, or can be cloned from our official git repository.


While being more updated, including new features and bugfixes, the version available in the git repository should be considered an under development stage. Therefore its stability is not guaranteed and it most likely lacks updated documentation.