Presented at
Black Hat USA 2021,
Aug. 4, 2021, 1:30 p.m.
(40 minutes)
<span>We present a novel class of DNS vulnerabilities that affect multiple DNS-as-a-Service (DNSaaS) providers. The vulnerabilities have been proven and successfully exploited on three major cloud providers including AWS Route 53 and may affect many others. Successful exploitation of the vulnerabilities may allow exfiltration of sensitive information from service customers' corporate networks. The leaked information contains internal and external IP addresses, computer names, and sometimes NTLM / Kerberos tickets. The root cause of the problem is the non-standard implementation of DNS resolvers that, when coupled with specific unintended edge cases on the DNS service provider's side, cause major information leakage from internal corporate networks. <br><br>In this research, we detail a specific vulnerability that is common across many major DNS service providers that leads to information leakage in connected corporate networks. Specifically, we show how Microsoft Windows endpoints reveal sensitive customer information when performing DNS update queries. The security risk is high. If an organization's DNS Updates are leaked to a malicious 3rd party, they reveal sensitive network information that can be used to map the organization and make operational goals. Internal IP addresses reveal the network segments of the organization; computer names hint at the potential content they may hold; external IP addresses expose geographical locations and the organization's sites throughout the world; and internal IPv6 addresses are sometimes accessible from the outside and allow an entry point into the organization. The impact is huge. Out of six major DNSaaS providers we examined, three were vulnerable to nameserver registration. <br><br>Any cloud provider, domain registrar, and website host who provides DNSaaS could be vulnerable. The number of organizations vulnerable to this weakness is shocking. Over a few hours of DNS sniffing, we received DNS Updated from 992,597 Windows endpoints from around 15,000 potentially vulnerable companies, including 15 Fortune 500 companies. In some organizations, there were more than 20,000 endpoints that actively leaked their information out of the organization. Exploiting the weakness is very easy. A single attacker with a single cloud account can get information on thousands of organizations in one step. There are several possible mitigations to this problem. We will review the solutions for both DNSaaS providers and managed networks.</span>
Presenters:
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Ami Luttwak
- Co-Founder & Chief Technology Officer, Wiz.io
Ami Luttwakis is a serial entrepreneur, an experienced cyber security CTO and a hacker at heart. Ami is mainly interested in cloud security and cloud exploits and understanding how the cloud is built to uncover its weaknesses. Ami is currently CTO of Wiz, the fastest growing unicorn in cloud security, and prior to that led research as CTO of Microsoft cloud security and founded Adallom, a pioneering cloud security start-up acquired by Microsoft in 2015.
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Shir Tamari
- Head of Research, Wiz.io
Shir Tamari is an experienced security and technology researcher specializing in vulnerability research and practical hacking. Shir is currently Head of Research of the cloud security company Wiz. In the past, he served as a consultant to a variety of security companies in the fields of research, development and product. Shir is also a member of the 5BC CTF team.
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