Research on the security of visual reasoning CAPTCHA

Yipeng Gao, Haichang Gao*, Sainan Luo, Yang Zi, Shudong Zhang, Wenjie Mao, Ping Wang, Yulong Shen, Jeff Yan

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution book

12 Citations (Scopus)

Abstract

CAPTCHA is an effective mechanism for protecting computers from malicious bots. With the development of deep learning techniques, current mainstream text-based CAPTCHAs have been proven to be insecure. Therefore, a major effort has been directed toward developing image-based CAPTCHAs, and image-based visual reasoning is emerging as a new direction of such development. Recently, Tencent deployed the Visual Turing Test (VTT) CAPTCHA. This appears to have been the first application of a visual reasoning scheme. Subsequently, other CAPTCHA service providers (Geetest, NetEase, Dingxiang, etc.) have proposed their own visual reasoning schemes to defend against bots. It is, therefore, natural to ask a fundamental question: are visual reasoning CAPTCHAs as secure as their designers expect? This paper presents the first attempt to solve visual reasoning CAPTCHAs. We implemented a holistic attack and a modular attack, which achieved overall success rates of 67.3% and 88.0% on VTT CAPTCHA, respectively. The results show that visual reasoning CAPTCHAs are not as secure as anticipated; this latest effort to use novel, hard AI problems for CAPTCHAs has not yet succeeded. Based on the lessons we learned from our attacks, we also offer some guidelines for designing visual CAPTCHAs with better security.

Original languageEnglish
Title of host publicationProceedings of the 30th USENIX Security Symposium
Place of Publication[S.I.]
Pages3291-3308
Number of pages18
ISBN (Electronic)9781939133243
Publication statusPublished - 13 Aug 2021
Event30th USENIX Security Symposium, USENIX Security 2021 - Virtual, Online
Duration: 11 Aug 202113 Aug 2021

Publication series

NameProceedings of the 30th USENIX Security Symposium

Conference

Conference30th USENIX Security Symposium, USENIX Security 2021
CityVirtual, Online
Period11/08/2113/08/21

Keywords

  • visual reasoning
  • cybersecurity
  • CAPTCHA

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