geedge.lantern.io
detection confidence: high public

The same TSG QA framework exercises live HTTP/HTTPS content-manipulation proxy actions -- redirect, replace, hijack, insert, and edit_element -- including a documented test case that adds a rule to replace "china"-related content in live Google search results, giving a concrete real-world target example for the platform's live content-injection/rewriting capability.

7a45ea05|2022-04-08|完成自动化用例及数据,串行形式代理策略动作:redirect,replace,hijack,insert,edit_element ; e0665c637|2021-08-16|用例调整,增加replace替换谷歌搜索china内容,增加monitor动作流量转发用例 (dongxiaoyan/gap_tsg_api.bundle)
censorsgeneric
productstsg
capabilitycontent-injection

extracted_by: claude-sonnet-5 · added 2026-08-26 · id: 2026-gap-tsg-content-injection

Related findings

detection

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.

detection

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.

detection

certstore's own commit history documents its transparent-TLS-MITM mechanics directly: it writes the client's observed SNI into the SAN field of the leaf certificate it mints on the fly, supports ECC issuance (secp192r1/secp256r1) for those forged certs, and reads its Trusted/Untrusted decryption-keyring configuration from MAAT's DECRYPTION_KEYRING table -- confirming the interception pipeline end-to-end: client SNI in, matching forged certificate out, gated by MAAT-synced keyring policy.

detection

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.

deployment

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.

detection

A production feature spec ("加密协议JG") requires detection-and-control capability for QUIC, ESNI, and ECH, with a per-connection log field c_encrypt_type explicitly distinguishing ClientHello encryption (0=unencrypted, 1=ESNI, 2=ECH) and a DF_QUIC_REGION rule table matching QUIC by SNI. The system computes a per-rule "CT" (穿透/penetration) rate from paired mirror-vs-functional RST-packet logs (TF-RST-LOG / TF-MIRROR-RST-LOG) to grade each block rule's effectiveness, and runs continuous active-verification probes against its own rules, deliberately varying the probe 4-tuple each run "to ensure it doesn't hit the blacklist" so the verification traffic itself reaches the target.