A user manual for a 'Malicious Service IPv6 Address Discovery and Assessment System' documents a sapp application-layer plugin (ipv6_domain.c) that extracts the HTTP Host header, TLS SNI, and DNS AAAA-record domain from live traffic and matches them against a malicious/blocked-domain list to resolve each hit's IPv6 address, alongside a separate active-probing pipeline (ZMapv6 + Entropy/IP-based address-space generation) used to discover IPv6 DNS resolvers and malicious-site IPv6 presence at internet scale.
在sapp平台运行sapp应用层插件ipv6_domain.c获取HTTP-HOST字段、SSL-SNI字段、DNS-AAAA记录中的域名并匹配。若命中,解析出域名对应的IPv6地址。
Related findings
Raw structured DNS event logs (dated 2021-08-23) captured from what appears to be a GFW-adjacent DNS monitoring/injection pipeline use a schema purpose-built for DNS response forgery ('CHEAT_TYPE', 'CHEAT_RCODE', 'CHEAT_STRATEGY', 'CHEAT_RR', 'INJECTED_PKT_FILE' fields) alongside per-query geolocation; sampled records show lookups for facebook.com and tiktokv.com originating from residential China Telecom/Unicom/Mobile subscriber IPs in Guangdong, Zhejiang, Anhui and other provinces, resolving against both domestic and foreign (8.8.8.8, OpenDNS) resolvers.
A 2023 MESA Lab monthly report describes the 'TF' project's active-defense work: test cases for serial ('串联') HTTP hijack/tamper and parallel ('并联') DNS race-injection ('DNS抢答'), performance tuning that scaled active-defense capacity from 3 to 5 units, converting two existing TSG boxes to active-defense mode, and rewriting the active-defense flow-control logic to no longer depend on sapp.
The same change document's post-deploy validation step explicitly checks that "spoofed packets and RST packets" are generated normally with no volume anomaly as routine production behavior, and the release separately adds a feature to retain full email body content (not just metadata) on business-user request, running on Kylin Linux Advanced Server V10.
TSG's firewall 'Deny' security-policy action is confirmed implemented via three interchangeable mechanisms: TCP RST injection, forged HTTP 404 response-page injection, and DNS-redirect. Confirmed via commits to MESA_Platform/sapp and tsg/tsg-os-buildimage GitLab repos (git.mesalab.cn).
The official SAPP platform manual ("Geedge Networks Confidential And Proprietary") documents an optional signature_enabled config flag that stamps sapp-injected TCP RST packets with a detectable pattern in the ip_id/ip_ttl/tcp_win fields so operators can later verify, via a Wireshark plugin or standalone tool, whether a given RST originated from a sapp instance -- the manual explicitly notes 100% recall but not guaranteed 100% precision. The manual separately documents that sapp supports three distinct wire-injection topologies (sys_route, vxlan_by_inline_device, raw_ethernet_single_gateway) and that its tcpdump_mesa debug tool has a dedicated "inject" packet class covering both TCP RST and forged DNS replies.
A MESA engineer wrote a SAPP business-layer plugin (v1 shipped to GitLab) that fingerprints network scanning/probing tools, producing a "scanning/probing tool fingerprint-database construction report." The companion fingerprint report documents Nmap's default host-discovery probe sequence (ICMP echo request, TCP SYN to port 443, TCP ACK to port 80, ICMP timestamp request) captured against a live target.