PanGu defines a configurable DNS response-spoofing subsystem (NTC_DNS_FAKE_IP_CB, NTC_DNS_RES_STRATEGY) supporting named 'answer groups' with a configurable number of fake answers returned per group (service ID 0x40 'dns欺骗'), i.e. DNS injection is a general, group-configurable policy primitive in TSG rather than a single hardcoded fake-IP response.
增加DNS响应策略配置表NTC_DNS_RES_STRATEGY ... 应答组的组号和应答组的应答数默认值为0，当用户指定应答组时（即组号大于0），应答数必须大于0
Defense implications
- DNS answer-spoofing is a configurable, group-based policy, not a single fixed sinkhole IP -- validate resolver defenses against multiple distinct injected-answer patterns, not just one poisoned IP.
Cited artifacts
mesalab_git—PanGu/PanGu_docs.bundle(git-commit-log)
Provenance pointers only — no leak content is rehosted. Raw material: Enlace Hacktivista.
Related findings
A 2020 MESA Lab monthly report describes building an encrypted-DNS gateway device and a self-hosted DoH server that was wired directly into a live "TSG platform WAN net interface", alongside a passive DoH-service-discovery pipeline that found 39 new DoH-serving domains in a single day of backbone ("科技网") traffic; a related note documents actively probing known DoH-serving IPs' upstream resolvers via a proxy network across 196 countries to check which still function.
Geedge fingerprinted several V2Ray-based VPN apps by their fixed API/bootstrap domains rather than protocol characteristics — blocking "V2 Pro" via pro.mucacherry.org, "V2 VPN" via v2.mucacherry.org, and "V2Net VPN" via api.v2net.live plus 5 rotating free-node domains (free1-5.v2n3t2.online / v2n3t.online) the app uses to fetch node lists.
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.
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.
TSG/CM ships with pre-built, first-class 'Learning Object' entries specifically for Freegate (Object ID 18) and Psiphon3 (Object ID 19), plus a generic 'Top Server IP' object (ID 20) -- default product features, not customer-commissioned custom signatures. The Psiphon3 object auto-learns and dynamically updates a live blocklist that reached roughly 70,000 IPs at one deployment before a database issue temporarily dropped it to ~50,000.
Crash-dump stack traces reveal TSG's core packet-processing engine (sapp) architecture: a custom multi-threaded C engine using 'marsio' as the DPDK-style packet-I/O driver, a plugin system for protocol handlers (confirmed: plug/protocol/http/http.so), and a libdocumentanalyze component that actively decompresses gzip content and parses ZIP/document formats found inside HTTP bodies -- i.e. inspection goes beyond headers into reconstructed application content.