Port-Scanning Improved

Architecture and Background

Fabian "Fabs" Yamaguchi & FX: New ideas for old practices - Port-Scanning improved How fast a port-scan can be is largely dependent on the performance of the network in question. Nonetheless, it is clear that choosing the most efficient scanning-speed is only possible based on sufficient information on the network's performance. We have thus designed and implemented a port-scanning method which provokes extra network-activity to increase the amount of information at our disposal in an attempt to gain speed on the long run. Following this approach, we've managed to mimic TCPs properties to an extend which allows us to implement many congestion control schemes initially designed for TCP.

Vulnerability Analysis

Further tweaking the actual implementation by integrating it into the linux-kernel left us with a port-scanner ready to tackle big networks at an impressive speed. Fabian "fabs" Yamaguchi currently studies computer-science and electrical engineering at the Berlin Institute of Technology where he focuses on data-communication and signal-processing. He has been working as a reverse-engineer and software-developer for Recurity Labs GmbH for about two years. During his school-time, he has worked on free-software projects such as the AfterStep-window-manager and he received the ArsDigita-Prize at MIT in 2001 for maintaining the "Young Programmer's Network", a community-project for young free-software-developers.

Exploitation and Demonstrations

Additionally, he has given presentations on port-scanning and bug-exploitation at the 24C3 and the 4th annual MNU congress in Berlin. Felix "FX" Lindner runs Recurity Labs. FX has over 10 years experience in the computer industry, eight of them in consulting for large enterprise and telecommunication customers. He possesses a vast knowledge of computer sciences, telecommunications and software development.

Remediation and Defensive Strategies

His background includes managing and participating in a variety of projects with a special emphasis on security planning, implementation, operation and testing using advanced methods in diverse technical environments. FX is well known in the computer security community and has presented his and Phenoelit's security research on Black Hat Briefings, CanSecWest, PacSec, DEFCON, Chaos Communication Congress, MEITSEC and numerous other events. His research topics included Cisco IOS, HP printers, SAP and RIM BlackBerry. Felix holds a title as State-Certified Technical Assistant for Informatics and Information Technology as well as Certified Information Systems Security Professional. For copies of the slides and additional materials please see the DEF CON 16 Archive here: