An IIE researcher's repo hswfp ('server-side fingerprinting experiment') packages written experiment steps and 'server-side fingerprinting experiment-related code' as a self-contained study, indicating active internal R&D into fingerprinting server/service implementations beyond the productized JA3/JA4 work already shipped in the SSL plugin.

A June 2024 internal MESA Team survey ('针对审查系统的科学研究及探测技术调研报告') catalogs the academic censorship-measurement toolkit (OONI, Augur, Satellite, Quack/Hyperquack, GFWatch, GFWeb, middlebox weaponization studies, traceroute-based middlebox localization, device fingerprinting) and separately reviews circumvention-tool countermeasures, explicitly naming Lantern alongside Psiphon, Tor Meek and Signal as tools using uTLS-style TLS ClientHello mimicry and domain-fronting.

The same T1/NTC node config (ntcconf/t1conf/main.conf, K18/Astana/Kazakhtelecom) exposes concrete DPI enforcement toggles: a SYNACK_OR_RST switch and SEND_INJECT_PKT flag governing active TCP-response/packet-injection behavior; ASN- and IP-based blocklists (ASN_MAAT, IPD_DYN_MAAT, IPD_STATIC_MAAT) refreshed from MAAT/Redis on a 1-second effect interval; a dynamic blacklist with a 180s timeout; explicit protocol-blocking switches for BitTorrent (DHT/uTP) and eMule (Kad); and TLS metadata harvesting including certificate SAN fields (NTC_SSL_COLLECT, collect_san_sw=1) streamed to a Kafka topic.

Exported AppSketch/MAAT signature-object JSON shows named per-VPN detection rules combining multiple independent vectors: CyberGhost's WireGuard variant is matched by a hex UDP-payload pattern (04000000*), destination port 1337, and ip.proto=17 together (signature cyberghostvpn_wireguard); Windscribe's OpenVPN control channel is matched by two offset-anchored hex byte patterns plus an exact 86-byte payload length (windscribevpn_openvpn_payload); and ExpressVPN is matched independently via a literal JA3 hash (ssl.analysis.ja3), FQDN strings (expressapisv2.com, www.expressvpn.works), and a large enumerated IP list (700+ individual ip.dst entries observed before the 200KB text-extraction cutoff).

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.

MAAT/AppSketch signatures "hotspotvpn_ja3" and "ultrasurfvpn_update_behavior" identify Hotspot VPN and Ultrasurf specifically via static JA3 TLS ClientHello hashes (e.g. f49621211538d12435b8498f195d0c31 for Hotspot VPN; 706ea0b1920182287146b195ad4279a6 and 1f0d8bb4fab11dc335dec2e69da0c36e for Ultrasurf), in Ultrasurf's case combined with an AND-condition on a set of legitimate-looking cover domains (skype.com, msn.com, microsoft update domains) — showing the DPI engine defeats Ultrasurf's domain-mimicry cover by fingerprinting the underlying TLS stack instead of trusting the SNI/host.

A 2020 MESA Lab monthly report describes building a sapp plugin that extracts packet-sequence features specifically "for DoH (DNS-over-HTTPS) service discovery," alongside a broader CSTNET DoH measurement-report effort and configuring a DNS-to-DoH gateway -- confirming sapp is used to fingerprint DoH traffic via statistical sequence features rather than plaintext DNS content.