Alexey Tyurin is a Russian pentester who is one of the leading developers of ERPScan Pentesting tool. In many of the systems he analyzed like SAP, VMware, and Citrix, he has found 0-day vulnerabilities.
He is one of the organizers of Defcon Russia.
He has participated in closing a major XML vector in SAP.
http://2012.zeronights.org/speakers