The SAT Móvil app (Mexico's official tax service, 1M+ downloads) consistently fetches its 'Chat' page over cleartext HTTP, exposing citizen ID numbers (CURP, RFC), passwords, and tax documents to any in-path attacker. None of the four major Latin American telco apps (MiTelcel, MiTigo, MiClaro, MiMovistar) implement HSTS on SMS-delivered external links, making all of them uniformly vulnerable to SSL strip downgrade attacks.

Chivo Wallet posts logs of every in-app event to NewRelic ('log-api.newrelic.com'), including keystrokes — DUI national ID numbers, phone numbers, and passwords — without privacy-policy disclosure. Separately, MiTelcel (76% Mexican mobile market share, 10M+ downloads) leaks users' phone numbers and emails to five distinct third-party servers via the HTTP 'referer' field on every 'Experiencias' tab click.

§7.1, §7.3, Table 2, Table 4 evaluation

The Chivo Wallet app — the official El Salvador government Bitcoin wallet with 1M+ downloads — uses Microsoft CodePush to check 'codepush.appcenter.ms' for JavaScript/HTML/CSS updates each time it opens, bypassing Google Play Store review entirely. This allows the government of El Salvador to push arbitrary behavioral changes to all users' devices without any app store vetting or user notification.

§7.3, Table 4 deployment

In Latin America, censorship predominantly takes the form of targeted surveillance coupled with physical threats rather than network-level blocking. Mexico had documented Pegasus infections on journalists and activists between 2019–2022, at least 25 private spyware vendors sold surveillance tools to Mexican federal and state police, and at least 119 journalists have been killed in Mexico since 2000. Dynamic analysis of 8 widely-used LATAM apps (combined 100M+ downloads) found security failures across all three assessed categories: cleartext traffic, undisclosed PII exfiltration to third parties, and unvetted external code update mechanisms.

§1, §2, §8 evaluation

MiClaro Colombia sends device latitude and longitude to multiple third-party servers without user disclosure, in violation of its own privacy policy. Among the four Movistar country variants, the Argentina app requests access to all phone-call-related permissions while the Uruguay app requests none — demonstrating that third-party SDK inclusion, background receivers, and dangerous permissions vary substantially by country version of the same ostensibly unified telco app.

§7.1, Table 2 evaluation

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

Longitudinal GFWeb data spanning 20 months shows the GFW actively patched previously-published evasion findings during the measurement period: overblocking bugs reported in academic papers were fixed, and fragmented-packet reassembly failures that researchers used to bypass blocking were corrected. This demonstrates that the GFW operator monitors published research and iterates on the system in response to disclosed vulnerabilities.

2024-hoang-gfweb Abstract, §5.4, §6 dpimiddlebox-interference

China's Great Firewall showed anomalous inconsistency: 13 test vectors produced mixed outcomes—TCP RST injection on some executions and a clean server response on others—with circumvention rates between 10% and 35% across 100 executions per vector. The authors attribute this to heterogeneous GFW infrastructure components applying different HTTP parsing logic, a departure from the GFW's usual consistency.

2024-m-ller-turning §5.2 dpirst-injectionkeyword-filteringmiddlebox-interference

Of 4,488 total HTTP Request Smuggling test vectors, 2,015 (44.9%) were accepted by at least one web server. CL*/TE vectors had a 99.0% acceptance rate (1,103/1,114); TE*/CL had 76.0% (859/1,130); CL/TE* had only 4.7% (53/1,130); and TE/CL* had 0%. Nginx 1.25.2 accepted 1,315 vectors while Apache 2.4.57 accepted only 11, reflecting HRS countermeasures added in Apache 2.4.25 and 2.4.52.

2024-m-ller-turning §5.1 / Table 1–4 dpimiddlebox-interference