M22's VPN signature-extraction workflow, when API sniffing (fiddler) fails, escalates to decompiling the target APK: jadx-gui, then apktool -- which recovered node information for "Luna VPN" after the first two methods failed.
第一轮尝试通过fiddler工具寻找api...第二轮...jadx-gui...第三轮...apktool工具对apk进行反编译解析，找到Luna VPN的节点信息
Defense implications
- Geedge routinely decompiles client APKs to recover hardcoded server/node lists -- client apps hardcoding server addresses in easily-decompiled form should be assumed discoverable this way regardless of network-level obfuscation.
Related findings
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.
M22's extraction against "VPN Hero" (OpenVPN-based) recovered 13 FQDN + 13 IP indicators; FQDNs follow a "zampakuto...shop" template. Post-signature testing in the Myanmar demo environment found no successful connections on Android/iOS.
Documents the exact methodology used to derive a block signature for 'Giti VPN': TLS interception (fiddler) to decrypt the app's traffic, identifying its control/initialization domain and a second per-session domain pattern, then blocking by those two domain-name features rather than deep packet content.
Project "M22" runs a standing weekly program to extract and patch detection signatures against "Turbo VPN": automated dial-testing continuously discovers server IPs (tens to hundreds/week), each batch packaged into a dated JSON patch file, validated for both blocking efficacy and false-positive risk before rollout. Ran continuously Aug-Nov 2024 in the source ticket.
M22 runs a large-scale automated pipeline against numerous commercial VPN apps: APK decompilation + HTTPS-proxy interception to extract servers/FQDNs, automated dial-testing at volume (one app: 17,554 dial-tests, 4,073 servers discovered, 94% 24-hour block rate), and OpenCV-based automated ad-dismissal to keep test automation running unattended.