Black Hat USA 2023


In this paper, we report MaginotDNS, a powerful cache poisoning attack against DNS servers that simultaneously act as recursive resolvers and forwarders (termed as CDNS). The attack is made possible through exploiting vulnerabilities in the bailiwick checking algorithms, one of the cornerstones of DNS security since the 1990s, and affects multiple versions of popular DNS software, including BIND and Microsoft DNS. Through field tests, we find that the attack is potent, allowing attackers to take over entire DNS zones, even including Top-Level Domains (e.g., .com and .net). Through a large-scale measurement study, we also confirm the extensive usage of CDNSes in real-world networks (up to 41.8% of our probed open DNS servers) and find that at least 35.5% of all CDNSes are vulnerable to MaginotDNS. After interviews with ISPs, we show a wide range of CDNS use cases and real-world attacks. We have reported all the discovered vulnerabilities to DNS software vendors and received acknowledgments from all of them. 3 CVE-ids have been published, and 2 vendors have fixed their software. Our study brings attention to the implementation inconsistency of security checking logic in different DNS software and server modes (i.e., recursive resolvers and forwarders), and we call for standardization and agreements among software vendors.

Aug 9, 2023 12:00 AM — 11:59 PM
3950 Las Vegas Blvd. South, Las Vegas, 89119

In Black Hat USA 2023, Professor Zhou Li presented our work: “The Maginot Line: Attacking the Boundary of DNS Caching Protection”.

Xiang Li
Xiang Li
Ph.D. Candidate in Cyberspace Security (Tsinghua University)

Xiang Li is a 5th-year Ph.D. candidate at the Institute of Network Science and Cyberspace, Tsinghua University, advised by Professors Qi Li and Haixin Duan. His research interests include network security, protocol security, IPv6 security, DNS security, Internet measurement, network & protocol fuzzing, network vulnerability discovery & attack, and underground economy with 18 research papers. As the first author, he has published many research papers at all top-tier security conferences, including Oakland S&P, USENIX Security, CCS, NDSS, and Black Hat (Asia, USA, and Europe). He applied for 11 patents (1 authorized and 5 in checking as the first author). He has obtained over 200 CVE/CNVD/CNNVD vulnerability numbers, more than $11,600 rewards, 330+ GitHub stars, multiple CERT reports, 100+ news coverage, and RFC acknowledgement. He got multiple prizes, such as 1st prize of IPv6 Technology Application Innovation Competition, 2nd prize of GeekCon 2023 DAF Contest, National Scholarship, Wang Dazhong Scholarship, Tsinghua Outstanding Scholarship, and Extraordinary Hacker of GeekCon International 2024.