1. aws DNS の脆弱性?
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Contents
/slide MS の問題のように思える。しかし、なぜ偽NSへ到達できるのか?
/DEFCON29 youtube
/Windows dynamic update 設定
A New Class of DNS Vulnerabilities Affecting Many DNS-as-Service Platforms Shir Tamari | Head of Research, Wiz.io Ami Luttwak | Co-Founder & Chief Technology Officer, Wiz.io Format: 40-Minute Briefings Tracks: CorpSec, Cloud & Platform Security
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.
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.
- こんな機能があるのか。危ない。
2. DNS Updates leak
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.
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.
3. Exploiting
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.