geedge.lantern.io
detection confidence: high public

TSG ships a first-class 'Mail Monitoring and Blocking' feature (confirmed in the product's own v24.08 deployment test checklist alongside HTTP/HTTPS Blocking, DNS Redirection and Monitoring, HTTPS Decryption, and HTTPS Manipulation) that parses SMTP/POP3/IMAP sessions to extract sender/recipient addresses. Field analysis at a Pakistan site found STARTTLS opportunistic encryption accounts for roughly 25-32% of mail sessions and measurably defeats this extraction -- when STARTTLS occurs, the session is logged but mail-address fields are empty. Engineering's response is to add an explicit flag field rather than recover the addresses.

上述会话decode_as会被标注为MAIL,但是mail_xx字段全部为空,原因是mail decoder在出现STARTTLS后...修改建议:参照SSL,新增mail.starttls flags日志字段

Defense implications

censorspk
techniquesdpi
productstsg
capabilitysubscriber-correlation

extracted_by: claude-sonnet-5 · added 2026-08-26 · id: 2026-mail-monitoring-starttls-gap

Related findings

deployment

This P19 (Pakistan) service is a pure Kafka-triggered file relay: for each Kafka record it deserializes a SysFileSync payload carrying a list of {source_oss_path, destination_oss_path} pairs alongside common_log_id, common_recv_time, common_schema_type, and processing_time -- fields matching the shared session/event-log schema used elsewhere in the MESA platform -- then HTTP-GETs each file from its source path and HTTP-POSTs it to its destination path. Distinct hosError/ossError/fileSyncError counters for the two legs (source read vs. destination write) show the two endpoints are operated as separate storage systems, one referred to in logs as "Hos" and the other as "Oss". Net effect: file objects tied to individually logged monitored sessions at the Pakistan site are relayed between storage tiers as a matter of routine pipeline operation, not just session metadata.

deployment

The repo galaxy/tsg_olap/p19-file-sync-service.bundle is a dedicated, site-scoped microservice explicitly namespaced for P19 -- this corpus's Pakistan deployment codename (site_codenames: "WMS-UTR / P19: Pakistan"). Its Docker image is built under the tsg/galaxy Harbor namespace (192.168.40.153:9080/tsg/galaxy/p19-file-sync-service), and its container WORKDIR/MAINTAINER are both "galaxy", directly confirming that Galaxy (the OLAP/big-data layer documented elsewhere in this taxonomy) ships individually-built, per-customer-site production services out of its tsg_olap subtree rather than only shared library code. The pom.xml calendar version (23.09.26) pins this specific build to Sept 26, 2023.

deployment

An internal TSG operations/troubleshooting manual lays out TSG's full traffic pipeline (NIC -> mrzcpd/marsio capture driver -> sapp DPI engine -> firewall/proxy(KNI->TFE)/active-defense/WAN-NAT policy branches) and shows engineers using maat_redis_tool to pull the live Redis-synced blocking policy tables (TSG_SECURITY_COMPILE, TSG_OBJ_IP_ADDR, TSG_OBJ_APP_ID) and filter them by numeric policy/object ID to debug why a block rule isn't firing.

detection

The internal 'MAAT网络流处理配置统一描述框架' engineering manual (v3.1.20, author name redacted, 2021) documents MAAT's Redis-synced rule-compilation framework and its RuleScan/Hyperscan-based pattern-matching engine (libmaatframe.so / librulescan), and records that RuleScan's fast-scan feature caused a production outage on 2019-03-19 and has been disabled ever since.

deployment

An 'ADC Hardware Installation and Configuration Guide' (v21.11) describes a modular chassis (Switch Sled, CPU Sled) matching taxonomy's Pakistan/WMS-UTR 'ADC hardware' reference, confirming ADC is a distinct deployed hardware line -- not just a site nickname -- with its own installation documentation separate from the TSG-X/TSG-7400 line.

detection

In the same live TSG capture, rows show ssl_ech_flag=1 recorded for real observed TLS sessions (to connect-api.guardianapp.com) alongside a populated ssl_ja3_hash and an intact ssl_sni value, and the session was still denied by name-based rule Deny_Brave. This confirms the DPI engine parses and logs the TLS ClientHello ECH extension as a distinct per-session flag in production/test traffic, i.e. ECH usage is visible to the gateway even though SNI in this particular capture was not itself encrypted from the classifier's point of view.