This fork aims to continue the work of the heavily modified version of Cuckoo Sandbox provided under the GPL by Optiv, Inc.

It offers a number of advantages over the upstream Cuckoo:

• Fully-normalized file and registry names
• 64-bit analysis
• Handling of WoW64 filesystem redirection
• Many additional API hooks
• Service monitoring
• Correlates API calls to malware call chains
• Ability to follow APC injection and stealth explorer injection
• Pretty-printed API flags
• Per-analysis Tor support
• Over 150 new signature modules (over 75 developed solely by Optiv)
• Anti-anti-sandbox and anti-anti-VM techniques built-in
• More stable hooking
• Ability to restore removed hooks
• Greatly improved behavioral analysis and signature module API
• Ability to post comments about analyses
• Deep hooks in IE's JavaScript and DOM engines usable for Exploit Kit identification
• Automatic extraction and submission of interesting files from ZIPs, RARs, RFC 2822 emails (.eml), and Outlook .msg files
• Direct submission of AV quarantine files (Forefront, McAfee, Trend Micro, Kaspersky, MalwareBytes, MSE/SCEP, and SEP12 formats currently supported)
• Automatic malware classification by Malheur
• Significant contributions from Jeremy Hedges, William Metcalf, and Kevin Ross
• Hundreds of other bugfixes

For more information on the initial set of changes, see: http://www.accuvant.com/blog/improving-reliability-of-sandbox-results

If you want to contribute to development, feel free to submit a pull request.