BISCUIT communicates using a custom protocol, which is then encrypted using SSL. Once installed BISCUIT will attempt to beacon to its command/control servers approximately every 10 or 30 minutes. It will beacon to its primary server first, followed by a secondary server. All communication is encrypted with SSL (OpenSSL 0.9.8i). ref. http://intelreport.mandiant.com/Mandiant_APT1_Report_Appendix.zip p.19