Holger is a long term security enthusiast started to work for Siemens as a telecommunication specialist building Hicom PBX systems and later networking systems. After passing the CCIE exam, he moved to Cisco 20 years ago, worked as penetration tester and security consultant for large customer projects. He did security research in a couple of sectors like botnet technology, sandbox bypassing, VPN MITM and developed several offensive and reverse engineering tools. He is the author of Dynamic Data Resolver (DDR).