Abstract
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.
In the 2023 32nd USENIX Security Symposium, I presented one paper “The Maginot Line: Attacking the Boundary of DNS Caching Protection” to the audiences. I met many old friends and made many new friends.
Xiang Li
Associate Professor (Nankai University)
Xiang Li is an Associate Professor at the College of Cyber Science, Nankai University. He is the advisor of Nankai University’s CTF teams, an ACM member, CCF member, and CIC member. He serves as PC for top-tier venues like IMC 2025 and others like AsiaCCS 2025. His research interests include network security, protocol security, IPv6 security, DNS security, Internet measurement, network & protocol fuzzing, network vulnerability discovery & attack, web security, 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, 370+ GitHub stars, multiple CERT reports, 100+ news coverage, and RFC acknowledgement. He got multiple prizes, such as 2024 ACM SIGSAC China Excellent Doctoral Dissertation Award, 2024 Pwnie Award Nominations (Hacker Oscar), 1st prize of IPv6 Technology Application Innovation Competition, 2nd prize of GeekCon 2023 DAF Contest, National Scholarship, Wang Dazhong Scholarship, Tsinghua Outstanding Scholarship, Outstanding Graduate, and Extraordinary Hacker of GeekCon International 2024.