geedge.lantern.io
detection confidence: medium public

A MESA Lab repo (handingkang/fakedns6-v2) implements an off-path DNS cache-poisoning tool built on the academic SADDNS2.0 side-channel attack (file path under ucr.edu/SADDNS2.0, GuessSeed.go plus a C guessSeed4.c), and a later commit explicitly removes "attack.sh"-related descriptions from the README -- consistent with an internally adapted DNS-spoofing/injection tool rather than a pure, undeployed academic replication.

src/ucr.edu/SADDNS2.0/GuessSeed.go Remove 'attack.sh'-related descriptions guessSeed4.c

Defense implications

techniquesdns-poisoning
capabilityactive-probing-impl

extracted_by: claude-sonnet-5 · added 2026-08-26 · id: 2026-fakedns6-saddns

Related findings

detection

Raw structured DNS event logs (dated 2021-08-23) captured from what appears to be a GFW-adjacent DNS monitoring/injection pipeline use a schema purpose-built for DNS response forgery ('CHEAT_TYPE', 'CHEAT_RCODE', 'CHEAT_STRATEGY', 'CHEAT_RR', 'INJECTED_PKT_FILE' fields) alongside per-query geolocation; sampled records show lookups for facebook.com and tiktokv.com originating from residential China Telecom/Unicom/Mobile subscriber IPs in Guangdong, Zhejiang, Anhui and other provinces, resolving against both domestic and foreign (8.8.8.8, OpenDNS) resolvers.

deployment

A 2023 MESA Lab monthly report describes the 'TF' project's active-defense work: test cases for serial ('串联') HTTP hijack/tamper and parallel ('并联') DNS race-injection ('DNS抢答'), performance tuning that scaled active-defense capacity from 3 to 5 units, converting two existing TSG boxes to active-defense mode, and rewriting the active-defense flow-control logic to no longer depend on sapp.

evaluation

An internal measurement-study report documents researchers live-testing the public DPYProxy TLS/SNI record-fragmentation tool against the GFW from inside China, against a control run from a German VPS. On a GFW IP-blocklisted Wikipedia IP, SNI fragmentation of any tested size (1/5/10/20 bytes) still ended in a server-side RST (though 1-5 byte fragments reached ServerHello before RST vs. 10-20 byte fragments RSTing right after ClientHello); on a non-blocklisted IP for the same domain, SNI fragmentation fully bypassed SNI-based blocking and returned a normal HTTP 200 response, matching the Germany baseline. The same report notes that testing Psiphon triggered roughly 5-10 minutes of residual censorship that also blocked other, unrelated circumvention tools from the same vantage point.

deployment

A design doc for a DNS/proxy gateway hosted at a public IIE-branded DoH endpoint (iie-public-doh.com) force-resolves the domains of ~40 target websites to a non-transparent SNI-routing proxy (which reads the ClientHello SNI without decrypting) while all other domains resolve normally; an 'open target resource discovery' module actively crawls each target site with a headless Chrome driver to map its dependent resource domains and assess their domestic-vs-overseas availability, feeding the allow-list.

detection

A user manual for a 'Malicious Service IPv6 Address Discovery and Assessment System' documents a sapp application-layer plugin (ipv6_domain.c) that extracts the HTTP Host header, TLS SNI, and DNS AAAA-record domain from live traffic and matches them against a malicious/blocked-domain list to resolve each hit's IPv6 address, alongside a separate active-probing pipeline (ZMapv6 + Entropy/IP-based address-space generation) used to discover IPv6 DNS resolvers and malicious-site IPv6 presence at internet scale.

detection

The "cyberghostvpn_servername" signature detects CyberGhost VPN by matching DNS query names against a list of the provider's own predictable backend node hostnames (e.g. blade6.singapore-rack456.nodes.gen4.ninja, blade5.frankfurt-rack486.nodes.gen4.ninja), showing the censor harvests and enumerates a VPN vendor's internal infrastructure-naming convention rather than relying only on client-facing domains.