A Myanmar deployment (M22 project) ticket requested Geedge R&D extract detection fingerprints for Signal (specifically targeting its anti-censorship "circumvention" toggle, currently evading blocking), LetsVPN, and LanternVPN — LanternVPN explicitly flagged lower priority with no fixed deadline given expected difficulty.
(1)对Signal应用封堵的需求,当该app打开"审查规避"的选项时,无法达到封堵的效果...(2)LetsVPN特征提取。(优先级高)(3)LanternVPN特征提取:已经和M业主讨论确认,不要求具体什么时间完成(可能花费时间较长)。(低)
Defense implications
- Lantern was an explicit, named fingerprinting target at a live Geedge/TSG Myanmar deployment as of mid-2024, though deprioritized as slow/difficult relative to Signal and LetsVPN — treat detection interest as confirmed, not hypothetical.
- Signal's own anti-censorship toggle was specifically noted as currently defeating TSG's blocking; worth studying what Signal does there for anything transferable.
Related findings
The TSG session_record schema in use at the Myanmar (YGN-MYTEL) deployment includes, in the same per-session record, both TLS-interception status fields (proxy_pinning_status, proxy_intercept_status, proxy_cert_verify, proxy_passthrough_reason, proxy_intercept_error) and individual-subscriber-identity fields (subscriber_id, imei, imsi, apn, phone_number) -- confirming MITM/certificate-interception capability and per-person subscriber correlation are built into the same live logging pipeline at an actual export site, not just described separately in marketing/config material.
Raw TSG session_record export logs dated Nov 2024, tagged device_group 'YGN-MYTEL' (Yangon, Mytel), directly corroborate the leak's M22=Myanmar/Mytel/Yangon site-codename mapping with live production data: individual SSL sessions are classified by app as 'Hotspot Shield VPN' (destination get.adobe.com, likely a fronting/CDN endpoint) and allowed under a named whitelist rule 'whitelist_102024', geolocated client-side as Myanmar.Yangon.Yangon.
TSG's app/protocol detection ("AppSketch" / context_based_detector plugin, part of the SAPP packet pipeline) is not purely static-signature: each detection rule can be an arbitrary Lua script (APP_SIG_LUA_SCRIPTS table) executed per-session in a per-worker-thread LuaJIT VM, with access to packet payload, session context counters, and helper functions (APP.data, APP.context.c2s_count, APP.log_debug, APP.append_extra_info). A validation CLI tool (luac-tool) checks script syntax, timeout, and return-value type before import.
Geedge ran an ongoing, systematically-numbered program extracting detection fingerprints for individual VPN and non-VPN apps for the Myanmar (M22) deployment, tracked with weekly-cadence per-app tickets; methodology combined packet capture, DNS/domain analysis, and fixed-port protocol identification, validated in a live test environment before shipping, with results tracked as "CT" (successfully blocked) or not.
Sustained, systematic feature-extraction campaign against ~20+ named commercial VPN apps (Secure VPN, VPN Turkey-series regional apps, Cloudbric, Thunder VPN, Quark VPN, TowerVPN, SymlexVPN, Tenta, tigerVPN, TLS Tunnel, Tomato VPN, VPNlat, VPNMonster, VPNPro, WhiteHatVPN, WolfVPN, and an ISAKMP/IKE-based and an OpenVPN-based app) for the Myanmar (M22) deployment, 2024. Methodology: reverse-engineer app API via Fiddler/mitm to enumerate server IP/FQDN lists where possible; fall back to Wireshark protocol-signature ID (e.g. recognizing raw ISAKMP port 500 or OpenVPN ports 1194/80) when APIs are unavailable; automated 'dial testing' (自动化拨测) continuously discovers new server IPs; ongoing re-verification explicitly tracks 'CT' (circumvention/breakthrough) to catch when a blocked app resumes working and needs a fingerprint update.
The M22 project ran a systematic, named feature-extraction program against multiple VPN apps — Express VPN, 7VPN, Master Nextgen, and Giti VPN — each ticket following the same workflow: extract signature in a lab environment, then run a false-positive ('误封') test in the Beijing environment before shipping to the field. Testing includes automated circumvention dial-testing (e.g. 17-hour looped Android tests).