Beyond the leak

This study presents one of the most extensive analyses of the lifecycle of leaked authentication credentials to date, bridging the gap between database breaches and real-world cyberattacks. We analyze over 27 billion leaked credentials—nearly 4 billion unique—using a sophisticated data filtering and normalization pipeline to handle breach inconsistencies. Following this analysis, we deploy a distributed sensor network of 39 honeypots running 14 unique services across 9 networks over a one-year-long experiment, capturing one of the most comprehensive authentication datasets in the literature. We analyze leaked credentials, SSH and Telnet session data, and HTTP authentication requests for their composition, characteristics, attack patterns, and occurrence. We comparatively assess whether credentials from leaks surface in real-world attacks. We observe a significant overlap of honeypot logins with common password wordlists (e.g., Nmap, John) and defaultlists (e.g., Piata, Mirai), and limited overlaps between leaked credentials, logins, and dictionaries. We examine generative algorithms (e.g., keywalk patterns, hashcat rules), finding they are widely used by users but not attackers—unless included in wordlists. Our analyses uncover unseen passwords and methods likely designed to detect honeypots, highlighting an adversarial arms race. Our findings offer critical insights into password reuse, mutation, and attacker strategies, with implications for authentication security, attack detection, and digital forensics.