About

Hi everyone 👋 - I am Florian and I am a last year PhD student at the University of Vienna's Security & Privacy Research Group (SEC) and the Network & Critical Infrastructure Security Group (ERIS) at SBA-Research.

During my master studies I joined Team ERIS as a junior researcher. With my supervisor Johanna, we found an entry point for Internet-measurements in Austria (aim.sba-research.org). I am now pursuing a PhD in that field with the focus on measuring Internet standard adoption and compliance.

My research focuses on tracking protocol adoption and security, the transition to IPv6, and leveraging active measurements to detect Internet outages.

Measurement Platforms

To make my measurements accessible to everyone, I try to build open measurement platforms.

Email Security
📧 Email Security

Ranks email servers.
IP Endpoint
📍 IP Endpoint

Tracks public IPs.

Talks

  • 🇦🇹 (Upcoming) 2025, Jun 25/26th, IKT, TBA (Dornbirn, AT).
  • 🇦🇹 2025, Feb 25th, Security Meetup, From Ping to Blackout: Active Measurements on Internet Disruptions in Ukraine Kherson (Dynatrace, Vienna, AT).
  • 🇦🇹 2025, Feb 24th, ATNOG 25/1, Von Österreich zur Ukraine und zurück: Aktive Messungen zum Erkennen von Internetausfällen (Linz AG, Linz, AT).
  • 🇦🇹 2024, Sept 18th, IKT, Analyse rerouting Internet in Kherson (Vienna, AT).
  • 🇪🇸 2024, Nov 05th, IMC, Destination Reachable: What ICMPv6 Error Messages Reveal About Their Sources (Madrid, ES).
  • 🇺🇸 2022, July, USENIX ATC, Not That Simple: Email Delivery in the 21st Century (Carlsbad, US).

Publications

Destination Reachable: What ICMPv6 Error Messages Reveal About Their Sources

F Holzbauer, Markus Maier, Johanna Ullrich
Proceedings of the 2024 ACM Internet Measurement Conference (IMC '24), 280-294

PAPER; SLIDES; CODE

BIBTEX 
@inproceedings{holzbauer2024reachable,
  title     = {Destination Reachable: What ICMPv6 Error Messages Reveal About Their Sources},
  author    = {Florian Holzbauer and Markus Maier and Johanna Ullrich},
  booktitle = {Proceedings of the 2024 ACM Internet Measurement Conference (IMC '24)},
  year      = {2024},
  location  = {Madrid, Spain},
  pages     = {1--15},
  publisher = {ACM},
  doi       = {10.1145/3646547.3688420},
}

Diffie-Hellman Picture Show: Key Exchange Stories from Commercial VoWiFi Deployments

GK Gegenhuber, F Holzbauer, PÉ Frenzel, E Weippl, A Dabrowski
33rd USENIX Security Symposium (USENIX Security '24), 451-468

PAPER; SLIDES; CODE ; MBN Parser

BIBTEX 
@inproceedings{gegenhuber2024diffie,
  title={Diffie-Hellman Picture Show: Key Exchange Stories from Commercial VoWiFi Deployments},
  author={Gegenhuber, Gabriel K and Holzbauer, Florian and Frenzel, Philipp {\'E} and Weippl, Edgar and Dabrowski, Adrian},
  booktitle={33rd USENIX Security Symposium (USENIX Security 24)},
  year={2024}
}

Careless Whisper: Exploiting Stealthy End-to-End Leakage in Mobile Instant Messengers

GK Gegenhuber, M Günther, M Maier, A Judmayer, F Holzbauer, PÉ Frenzel, Johanna Ullrich
arXiv preprint arXiv:2411.11194 (2024)

BIBTEX 
@article{gegenhuber2024careless,
  title={Careless Whisper: Exploiting Stealthy End-to-End Leakage in Mobile Instant Messengers},
  author={Gegenhuber, Gabriel K and Guenther, Maximilian and Maier, Markus and Judmayer, Aljosha and Holzbauer, Florian and Frenzel, Philipp {\'E} and Ullrich, Johanna},
  journal={arXiv preprint arXiv:2411.11194},
  year={2024}
}
An Extended View on Measuring Tor AS-Level Adversaries

GK Gegenhuber, M Maier, F Holzbauer, W Mayer, G Merzdovnik
Computers & Security 132, 103302 (2023)

BIBTEX 
@article{gegenhuber2023extended,
  title={An extended view on measuring tor as-level adversaries},
  author={Gegenhuber, Gabriel K and Maier, Markus and Holzbauer, Florian and Mayer, Wilfried and Merzdovnik, Georg and Weippl, Edgar and Ullrich, Johanna},
  journal={Computers \& Security},
  volume={132},
  pages={103302},
  year={2023},
  publisher={Elsevier}
}
Not That Simple: Email Delivery in the 21st Century

F Holzbauer, J Ullrich, M Lindorfer, T Fiebig
USENIX Annual Technical Conference (USENIX ATC '22), 295-308 (2022)

PAPER; SLIDES; APNIC-Blog; CODE

BIBTEX 
@inproceedings {holzbauer2022email,
author = {Florian Holzbauer and Johanna Ullrich and Martina Lindorfer and Tobias Fiebig},
title = {Not that Simple: Email Delivery in the 21st Century},
booktitle = {2022 USENIX Annual Technical Conference (USENIX ATC 22)},
year = {2022},
isbn = {978-1-939133-29-18},
address = {Carlsbad, CA},
pages = {295--308},
url = {https://www.usenix.org/conference/atc22/presentation/holzbauer},
publisher = {USENIX Association},
month = jul
}

IPv6-Reconnaissance - Internet-weite Analyse von ICMPv6

F Holzbauer
Master Thesis, University of Applied Sciences St. Pölten (2020)

Awards

🏆 Netidee Stipend (10.000€) for my doctoral thesis with the title: Measuring the Gap between Standardization, Implementation and Adoption of Internet Standards

BLOG; STIPEND