The same ADC/TSG-OS installation guide's built-in factory acceptance test ("tsg-diagnose-oneshot") enumerates the product's certified MITM/content-manipulation actions as standard, tested features of every deployment: SSL interception with expired/self-signed/untrusted-root cert handling, and both SSL and HTTP proxy policies supporting redirect, block, replace, hijack, and insert actions, plus DNS request handling with drop and A/AAAA redirect (including TTL-range variants). This is vendor self-documentation, not inferred behavior.
test_proxyPolicy_ssl_replace ... test_proxyPolicy_ssl_hijack ... test_proxyPolicy_ssl_insert ... test_proxyPolicy_http_replace ... test_proxyPolicy_http_hijack ... test_proxyPolicy_http_insert ... test_dnsRequest_deny_redirect_a_range_ttl ... test_dnsRequest_deny_redirect_aaaa_range_ttl
Defense implications
- Live HTTP/TLS response replace/hijack/insert is a standard, factory-certified capability on every fielded unit, not an exceptional or rare configuration — protocol designs should assume any MITM'd session can have its content actively rewritten, not merely blocked or logged.
- DNS redirect responses support explicit TTL control, so DNS-based circumvention that relies on short client-side caching windows to outrun injected records may not gain much protection here.
Related findings
TSG's own policy API documentation (tsg/tsg-doc) defines dedicated database/API objects for live content manipulation: a content-hijack policy-file table (内容劫持策略文件) with a contentName field, and an injected-script policy-file table (注入脚本) with an insertOn (injection point) field, alongside a block-page (访问阻断页面) policy-file type — confirming content injection and block-page replacement are first-class, documented TSG policy actions.
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 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.
An internal TSG troubleshooting runbook ("HTTPS证书替换策略无效果") documents the certstore MITM-certificate service actively serving/validating forged certificates keyed by SNI, walking an operator through checking certstore logs for specific real-world domains including Google's update service (update.googleapis.com) and Nvidia's GFE service (services.gfe.nvidia.com), and cross-checking keyring config live via maat_redis_tool.
certstore's own commit history documents its transparent-TLS-MITM mechanics directly: it writes the client's observed SNI into the SAN field of the leaf certificate it mints on the fly, supports ECC issuance (secp192r1/secp256r1) for those forged certs, and reads its Trusted/Untrusted decryption-keyring configuration from MAAT's DECRYPTION_KEYRING table -- confirming the interception pipeline end-to-end: client SNI in, matching forged certificate out, gated by MAAT-synced keyring policy.
Production network-topology docs for the Astana and Almaty (Kazakhstan / K18) sites show a live decrypted-traffic forwarding pipeline between an ADC front-end and an ASEM front-end over a direct fiber link, plus a distinct 'IP Spoofing' business function and dedicated static/dynamic proxy interception business lines, and a certificate-management endpoint (port 9991) — confirming operational TLS interception (MITM) infrastructure in production, not just lab capability, at both K18 sites.