Three-Way Dissection of a Game-CAPTCHA: Automated Attacks, Relay Attacks, and Usability
Abstract
Existing captcha solutions on the Internet are a major source of user frustration. Game captchas are an interesting and, to date, little-studied approach claiming to make captcha solving a fun activity for the users. One broad form of such captchas -- called Dynamic Cognitive Game (DCG) captchas -- challenge the user to perform a game-like cognitive task interacting with a series of dynamic images. We pursue a comprehensive analysis of a representative category of DCG captchas. We formalize, design and implement such captchas, and dissect them across: (1) fully automated attacks, (2) human-solver relay attacks, and (3) usability. Our results suggest that the studied DCG captchas exhibit high usability and, unlike other known captchas, offer some resistance to relay attacks, but they are also vulnerable to our novel dictionary-based automated attack.
Keywords
Cite
@article{arxiv.1310.1540,
title = {Three-Way Dissection of a Game-CAPTCHA: Automated Attacks, Relay Attacks, and Usability},
author = {Manar Mohamed and Niharika Sachdeva and Michael Georgescu and Song Gao and Nitesh Saxena and Chengcui Zhang and Ponnurangam Kumaraguru and Paul C. van Oorschot and Wei-Bang Chen},
journal= {arXiv preprint arXiv:1310.1540},
year = {2013}
}
Comments
16 pages, 10 figures