Back to School: On the (In)Security of Academic VPNs


Ka Lok Wu, The Chinese University of Hong Kong; Man Hong Hue, The Chinese University of Hong Kong and Georgia Institute of Technology; Ngai Man Poon, The Chinese University of Hong Kong; Kin Man Leung, The University of British Columbia; Wai Yin Po, Kin Ting Wong, Sze Ho Hui, and Sze Yiu Chau, The Chinese University of Hong Kong


This paper is under embargo and will be on the first day of the symposium.

In this paper, we investigate the security of academic VPNs around the globe, covering various protocols that are used to realize VPN services. Our study considers 3 aspects that can go wrong in a VPN setup, which include (i) the design and implementation of VPN front-ends, (ii) the client-side configurations, and (iii) the back-end configurations. For (i), we tested more than 140 front-ends, and discovered numerous design and implementation issues that enable stealthy but severe attacks, including credential theft and remote code execution. For (ii), we collected and evaluated 2097 VPN setup guides from universities, and discovered many instances of secret key leakage and lack of consideration to potential attacks, leaving many client-side setups vulnerable. Finally, for (iii), we probed more than 2000 VPN back-ends to evaluate their overall health, and uncovered some concerning configuration and maintenance issues on many of them. Our findings suggest that severe cracks exist in the VPN setups of many organizations, making them profitable targets for criminals.