The same SSL plugin added explicit detection of the Encrypted Client Hello extension (type 0xFE0D) with test cases in June 2023, and separately implements JA3/JA3S (2020) and JA4/JA4S (2024) TLS client/server fingerprint calculation as first-class features -- so TSG-class DPI can flag 'ECH is in use' even without decrypting it, and independently fingerprints TLS stacks via JA3/JA4.
支持识别ECH（扩展类型为0xFE0D），并增加测试用例 ... Feature: Support calculating JA4/JA4S fingerprint
Defense implications
- ECH hides the SNI's contents but its presence (extension 0xFE0D) is still visible to this DPI and could be used as a block/flag signal on its own -- don't assume ECH gives full protocol-level cover.
- JA3/JA4/JA4S fingerprinting is productized here -- a Lantern TLS client that doesn't randomize/mimic a common JA3/JA4 fingerprint is trivially distinguishable regardless of SNI/ECH handling.
Related findings
The same 224-column TSG per-session log schema carries a full TLS- interception field set — proxy_pinning_status, proxy_intercept_status, proxy_passthrough_reason, proxy_cert_verify, proxy_intercept_error, sc_rsp_raw and sc_rsp_decrypted (raw vs. decrypted server response content) — plus ssl_esni_flag and ssl_ech_flag (explicit ECH/ESNI-usage flags), ssl_ja3_hash/ssl_ja3s_hash, and ssh_hassh (SSH client fingerprinting), confirming certstore-style MITM interception, ECH/ESNI detection, and TLS/SSH fingerprinting are all first-class fields logged on every session, not experimental add-ons.
A raw TSG session-log export shows the full production log schema: per-flow fields include subscriber_id, imei, imsi, phone_number and apn alongside ssl_ja3_hash/ja3s_hash, ssl_esni_flag, ssl_ech_flag, quic_sni, dtls_ja3_fingerprint, and proxy_pinning_status/proxy_intercept_status/ proxy_cert_verify fields for the MITM proxy path. This confirms TSG's session logging natively joins network-flow identity to subscriber identity and captures TLS fingerprint/ESNI-ECH state and MITM-interception outcome in the same record.
Two independently-leaked TSG session-log CSV exports share an identical 224-field schema whose proxy_* columns (proxy_action, proxy_pinning_status, proxy_intercept_status, proxy_cert_verify, proxy_intercept_error) log the outcome of TLS interception per session, alongside ssl_ja3_hash/ssl_ja3s_hash, ssl_esni_flag, ssl_ech_flag, and quic_sni fields — confirming MITM/cert-pinning-bypass instrumentation and TLS/QUIC fingerprinting are built into TSG's standard traffic-logging pipeline, not a bolt-on feature.
A leaked TSG session-log CSV schema (device XXG-TSG-BJ) includes built-in per-session fields for TLS interception status (proxy_intercept_status, proxy_cert_verify, proxy_pinning_status, proxy_passthrough_reason) alongside JA3/JA3S TLS fingerprints and explicit ssl_esni_flag/ssl_ech_flag columns, confirming TSG logs whether a session was MITM'd and whether it used ECH/ESNI.
The full TSG session-log CSV schema header discloses the complete set of per-session fields the platform records, including TLS JA3/JA3S fingerprint hashes, explicit ssl_esni_flag/ssl_ech_flag columns, QUIC/DTLS SNI and JA3 fields, and direct subscriber-identity fields (subscriber_id, imei, imsi, apn, phone_number) captured on every logged session alongside ordinary network 5-tuple data.
MESA_Platform's "quic" module (built and packaged as stellar-on-sapp/sapp RPMs) implements SNI/User-Agent extraction from both cleartext GQUIC (versions 23-59) and encrypted IETF QUIC RFC9000 ClientHello payloads, and supports a QUIC SNI whitelist -- i.e. the DPI pipeline decrypts/parses encrypted QUIC handshakes to recover the destination domain rather than being blocked by QUIC's encryption.