2 citations · 2 across the 14 of their papers we have counts for
14 papers
Send and Pretend: Exploiting Transcript Consistency Issues in End-to-End Encrypted Group Chats
Gabriel K. Gegenhuber, Moritz Grefner, Maximilian Günther +3
End-to-end encrypted (E2EE) messaging apps are widely praised for their security and thus also used for sensitive coordination in group chats (e.g., by political decision makers).…
Democratizing Measurement of Critical Mobile Infrastructure: Security and Privacy in an Increasingly Centralized Communication Ecosystem
Gabriel K. Gegenhuber
Cellular networks serve as the backbone of global communication, providing critical access to telephony and the Internet, often in regions lacking alternatives. However, the growin…
A Relay a Day Keeps the AirTag Away: Practical Relay Attacks on Apple's AirTags
Gabriel K. Gegenhuber, Leonid Liadveikin, Florian Holzbauer +1
Apple AirTags use Apple's Find My network: when nearby iDevices detect a lost tag, they anonymously forward an encrypted location report to Apple, which the tag's owner can then fe…
Context Matters: Repository-Aware Security Analysis of the Agent Skill Ecosystem
Florian Holzbauer, David Schmidt, Gabriel Gegenhuber +2
Agent skills extend local AI agents, such as Claude Code and OpenClaw, with additional functionality. Their growing popularity has led to dedicated marketplaces resembling mobile a…
Hey there! You are using WhatsApp: Enumerating Three Billion Accounts for Security and Privacy
Gabriel K. Gegenhuber, Philipp É. Frenzel, Maximilian Günther +2
WhatsApp, with 3.5 billion active accounts as of early 2025, is the world's largest instant messaging platform. Given its massive user base, WhatsApp plays a critical role in globa…
SIMulator: SIM Tracing on a (Pico-)Budget
Gabriel K. Gegenhuber, Philipp É. Frenzel, Adrian Dabrowski
SIM tracing -- the ability to inspect, modify, and relay communication between a SIM card and modem -- has become a significant technique in cellular network research. It enables e…
Prekey Pogo: Investigating Security and Privacy Issues in WhatsApp's Handshake Mechanism
Gabriel K. Gegenhuber, Philipp É. Frenzel, Maximilian Günther +1
WhatsApp, the world's largest messaging application, uses a version of the Signal protocol to provide end-to-end encryption (E2EE) with strong security guarantees, including Perfec…
Careless Whisper: Exploiting Silent Delivery Receipts to Monitor Users on Mobile Instant Messengers
Gabriel K. Gegenhuber, Maximilian Günther, Markus Maier +4
With over 3 billion users globally, mobile instant messaging apps have become indispensable for both personal and professional communication. Besides plain messaging, many services…
Diffie-Hellman Picture Show: Key Exchange Stories from Commercial VoWiFi Deployments
Gabriel Karl Gegenhuber, Florian Holzbauer, Philipp Frenzel +2
Voice over Wi-Fi (VoWiFi) uses a series of IPsec tunnels to deliver IP-based telephony from the subscriber's phone (User Equipment, UE) into the Mobile Network Operator's (MNO) cor…
Never Gonna Give You Up: Exploring Deprecated NULL Ciphers in Commercial VoWiFi Deployments
Gabriel Karl Gegenhuber, Philipp Frenzel, Edgar Weippl
In today's cellular network evolutions, such as 4G and 5G, the IMS (IP Multimedia Subsystem) serves as a crucial component in managing voice calls and handling short messages. Besi…
Why E.T. Can't Phone Home: A Global View on IP-based Geoblocking at VoWiFi
Gabriel Karl Gegenhuber, Philipp Frenzel, Edgar Weippl
In current cellular network generations (4G, 5G) the IMS (IP Multimedia Subsystem) plays an integral role in terminating voice calls and short messages. Many operators use VoWiFi (…
An Extended View on Measuring Tor AS-level Adversaries
Gabriel Karl Gegenhuber, Markus Maier, Florian Holzbauer +4
Tor provides anonymity to millions of users around the globe which has made it a valuable target for malicious actors. As a low-latency anonymity system, it is vulnerable to traffi…
MobileAtlas: Geographically Decoupled Measurements in Cellular Networks for Security and Privacy Research
Gabriel Karl Gegenhuber, Wilfried Mayer, Edgar Weippl +1
Cellular networks are not merely data access networks to the Internet. Their distinct services and ability to form large complex compounds for roaming purposes make them an attract…
Zero-Rating, One Big Mess: Analyzing Differential Pricing Practices of European MNOs
Gabriel Karl Gegenhuber, Wilfried Mayer, Edgar Weippl
Zero-rating, the practice of not billing data traffic that belongs to certain applications, has become popular within the mobile ecosystem around the globe. There is an ongoing deb…