Application packaging and software supply chains in Russia's Android ecosystem can expand the effective TLS trust boundary beyond OS-level controls, enabling MITM attacks on TLS connections for apps that bundle or inherit Russian-controlled certificate authorities. This bypasses the assumption that the OS trust store constrains which CAs can intercept encrypted traffic.

RuStore provides a state-adjacent software supply chain through which APKs containing certificate material can reach Russian Android users at scale, creating a vector for expanding TLS trust anchors outside the OS trust store and outside Google's certificate governance. The 2022 sanctions that drove RuStore adoption also concentrated this distribution power in domestically controlled infrastructure.

Abstract deployment

A measurement study of RuStore — Russia's domestic Android marketplace promoted after 2022 sanctions isolated Russian users from Google Play — finds that APKs bundle certificate material and trust-configuration artifacts independently of the OS trust store. The study combines ecosystem-wide measurement with a weighted top-application analysis to characterize how this app-level certificate bundling expands the effective TLS trust boundary.

Abstract evaluation

The paper directly challenges the assumption that TLS provides a sufficient security fallback against hostile networks, demonstrating that Russia's Android ecosystem enables trust-anchor expansion through app packaging that undermines OS trust store boundaries. The implication is that TLS interception in Russia may be feasible at the app level without requiring OS-level compromise or user consent.

Abstract policy

Iran's censorship infrastructure began dropping all fragmented TLS ClientHello packets around late July 2026, rendering the tlshello fragmentation bypass technique non-functional. The blocking took effect approximately July 27, 2026, based on user-reported timelines in the net4people/bbs community report.

2026-spiderxss-tlshello-fragmentation-not Issue body (Jul 31 2026) dpisni-blockingmiddlebox-interference

After approximately four days, Iran placed Cloudflare IP ranges behind a NAT that performed full TCP reassembly with strict checksum and sequence-number validation; any packet with an incorrect checksum or out-of-window sequence number caused immediate connection teardown, eliminating both TTL-spoofing and sequence-desynchronization bypasses.

2026-tuleo1-internet-analysis-shutdown Issue body sni-blockingdpimiddlebox-interference

Two TCP-layer SNI-spoofing techniques briefly circumvented Iran's DPI for approximately four days: (1) sending a fake ClientHello with a TTL too low to reach the server but high enough to pass the censor, and (2) sending a fake ClientHello at a future TCP sequence number that the server would ignore but the stateless DPI would accept. Both were defeated once Iran placed Cloudflare IPs behind a stateful NAT that validated checksums and sequence numbers. Iran's SNI whitelist permitted only specific domains, hcaptcha.com among them.

2026-tuleo1-internet-analysis-shutdown Issue body (SNI spoofing methods paragraph) dpisni-blockingmiddlebox-interference

Russian TSPU devices directly block ECH by dropping ClientHello messages that contain both an ECH extension and the outer SNI hostname "cloudflare-ech.com" — the static outer SNI Cloudflare advertises in all its ECH configurations. Blocking affects both TLS and QUIC. ECH connections to servers with Cloudflare ECH support but outside Cloudflare's official IP ranges are NOT blocked. TCP segmentation alone or TLS record fragmentation alone did NOT bypass TSPU ECH blocking, but combining both techniques did circumvent it. TSPU has also added TCP reassembly capabilities that defeat previously effective fragmentation-only bypasses.

2025-niere-encrypted §5, Figure 5 dpirst-injectionmiddlebox-interference

The GFI's HTTP and HTTPS filters are now stateful (requiring initial SYN packet with matching sequence numbers) and have been activated on all TCP ports—not only standard ports 80 and 443 as reported by prior studies. This is a significant departure from previous work that found stateless HTTP/HTTPS blocking limited to standard ports. The HTTP filter injects a 403 Forbidden blockpage (not RST packets as used by the GFW), while HTTPS injects a single RST+ACK packet. The GFI also exhibits TCP non-compliance (not requiring a full three-way handshake to trigger filtering), enabling outside-in measurement without in-country servers.

2025-tai-irblock §2.1, §3.2 dpirst-injectionpacket-injectionmiddlebox-interference

The Henan Firewall is stateless in two exploitable ways: (1) it requires the TCP header to be exactly 20 bytes—enabling any TCP option (e.g., TCP Timestamps, which Windows disables by default) to bypass it entirely; (2) it does not perform TCP reassembly, so splitting a TLS ClientHello across two TCP segments such that the SNI extension straddles the boundary bypasses the censor. Both bypasses require only client-side changes and have already been implemented in Xray, GoodbyeDPI, and Shadowrocket. TLS record fragmentation (splitting the ClientHello across multiple TLS records within one TCP segment) also defeats both the Henan Firewall and the GFW, since neither performs TLS reassembly.

2025-wu-regional-censorship §4.3 / §6 sni-blockingdpimiddlebox-interference