TSG's SSL/IPD logging schema records a hit_pos field on every SSL-blocking log entry (NTC_SSL_LOG, IPD_SSL_IP_LOG) whose value is explicitly one of SNI, SAN, or CN -- confirming TSG's TLS-blocking decision can be attributed to, and therefore driven by, the certificate's SAN or CN fields, not only the ClientHello SNI extension.
NTC_SSL_LOG，IPD_SSL_IP_LOG日志表新增命中位置字段hit_pos，类型为字符串，取值取值为：SNI、SAN、CN之一
Defense implications
- Domain-fronting / SNI-hiding defenses must also ensure the actual leaf certificate's SAN/CN fields don't reveal the true backend -- TSG explicitly logs and can match on SAN/CN independent of the ClientHello SNI.
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 confirmed bypass — TSG failed to extract SNI from TLS ClientHello when the SNI extension appeared later than expected in the extension list, letting those flows through unblocked (and incidentally TLS 1.3 flows generally, since clients fell back to 1.3 after 1.2 was blocked); fixed on-site via a patch to the "ssl.so" detection plugin.
TSG automatically generates recurring weekly "SNI Report of Overseas APP" and companion "Server IP and Location of Overseas APP" reports at what is almost certainly a China-national (not export-customer) scale — single weekly runs process from ~5.7 trillion to over 135 billion rows and up to ~775TB/week — breaking down QUIC.SNI/SSL.SNI/HTTP.Host traffic per named blocked-in-China platform (YouTube, Facebook, Google, Twitter, Instagram, Telegram, WhatsApp, Netflix, BBC, Viber, Line, Snapchat, Gmail, HBO, and more), down to individual CDN edge hostnames (e.g. specific scontent-*.fbcdn.net and rr*---sn-*.googlevideo.com nodes ranked by bytes). The report series recurs weekly from at least Feb 2023 through Mar 2024.
A dedicated internal "运营商前端分析团队" (Carrier Front-end Analysis Team) produces weekly, carrier-specific traffic-analysis reports explicitly titled "新疆移动流量分析报告" (Xinjiang Mobile Traffic Analysis Report) and "新疆联通流量分析报告" (Xinjiang Unicom Traffic Analysis Report), with instances dated from at least July 2022 through March 2024. One instance (Xinjiang Mobile, 2023-05-15) reports total carrier bandwidth of 4.4Tbps (1Tbps access bandwidth), 27.34PB of weekly throughput, 123 distinct identified application-layer protocols, and a section (4.1, pages 17+) explicitly tracking server IP/location for 28 named overseas apps (BBC, Discord, ESPN, Facebook, Gmail, Google, Hulu, Instagram, Netflix, Reddit, Skype, Telegram, Twitter, Uber, WhatsApp, Wikipedia, YouTube, Zoom, etc.).
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.
TSG implements heuristic tunnel-protocol detection distinguishing Teredo (IPv6-over-UDP, default port 3544) from GTP tunneling based on UDP payload inspection, used to decide 'innermost' session attribution for firewall matching.
Recurring automated "Tiangou Secure Gateway — SNI Report of Overseas APP" documents (weekly, multiple recurrences across 2023-2024) enumerate every distinct QUIC.SNI/SSL.SNI/HTTP.Host value observed per major foreign platform (Netflix, WhatsApp, Telegram, Twitter, YouTube, Signal- adjacent services, etc.) with packet/byte counts, processing runs at up to ~6.3 trillion rows per report. QUIC SNI is tracked as a distinct column from TLS SNI, showing the pipeline separately fingerprints HTTP/3 traffic.