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Episode #818 Quiz

News from the DarkSide
Date: 2021-05-11 | Length: 1.5 hrs | Episode page at twit.tv

About this episode

TsuNAME exploits cyclic DNS records to trap naive recursive resolvers in infinite lookup loops, generating thousands of queries per second and amplifying traffic against authoritative servers. Google and Cisco patched affected resolvers. Separately, Exim’s 21 vulnerabilities, many remote and longstanding, threaten widely deployed mail servers and require immediate updates.

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Question 1: According to the TsuNAME discussion, what specific condition allows a recursive DNS resolver to get trapped into repeatedly querying authoritative servers?

Question 1

According to the TsuNAME discussion, what specific condition allows a recursive DNS resolver to get trapped into repeatedly querying authoritative servers?

An authoritative server returns truncated responses that force TCP fallback A resolver receives too many identical queries from caching forwarders A domain is misconfigured with cyclic dependent DNS records A resolver ignores EDNS0 buffer sizes and retries the query endlessly

Question 2: What were the two resolver products that the episode says failed the authors' manual cyclic-loop testing before being fixed?

Question 2

What were the two resolver products that the episode says failed the authors' manual cyclic-loop testing before being fixed?

KnotDNS and Quad9 Cloudflare DNS and OpenNIC Cisco OpenDNS and Google DNS Unbound and BIND

Question 3: What did the Google blog post on 2SV say would start happening for some accounts, according to the episode's discussion?

Question 3

What did the Google blog post on 2SV say would start happening for some accounts, according to the episode's discussion?

Users would be migrated to a passwordless enterprise SSO only Users would be automatically enrolled in two-step verification Users would be required to replace passwords with hardware keys Users would be forced to use app passwords for every sign-in

Question 4: Which pair of Tor-related attacks did Nusenu say the malicious exit relays were using to manipulate user traffic?

Question 4

Which pair of Tor-related attacks did Nusenu say the malicious exit relays were using to manipulate user traffic?

DNS cache poisoning and cookie replay BGP hijacking and certificate stapling abuse TLS downgrade and SSH key substitution SSL stripping and bitcoin address rewriting

Question 5: What approximate share of Tor exit capacity did Nusenu report this malicious entity had reached at its peak?

Question 5

What approximate share of Tor exit capacity did Nusenu report this malicious entity had reached at its peak?

About 27.5 percent of exit capacity About 12 percent of exit capacity About 40 percent of exit capacity About 5 percent of exit capacity

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