#2

Это действительно какой-то фильтр TLS.

newpipe_youtube_notworking.zip (21.6 KB)
termux_curl_youtube_working.zip (1.7 MB)

Домен www.youtube.com резолвится в 173.194.220.198, но в случае NewPipe с сервера не приходит ответ на ClientHello.
Запрос к https://www.youtube.com на тот же IP-адрес через cURL работает без проблем.

#3

Еще один PCAP-файл, присланный пользователем программы.

По сообщениям пользователей, смена DNS возвращает работоспособность программе, предположительно, из-за другого IP-адреса домена www.youtube.com — фильтр включён с ограничением по адресу.

NewPipe_dns_issue.zip (1.2 KB)

#4

Comment

Phone A
× not working using mobile data (Beeline)
× not working using wifi wired connection (Dom.ru)

Phone B
✓ working using mobile data (Yota)
× not working using wifi wired connection (Dom.ru)

When I switch to mobile data (Yota), request channel list or video, it works like it should.
After that if I switch back to wi-fi (Dom.ru) it keeps working for some time and then stops loading anything again. In one case it worked for about 1 hour, in other for about 30 minutes

#5

Команда для проверки:

echo "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" | xxd -ps -r | nc -v 173.194.220.198 443 > /dev/null
#6

This is filter works specifically for www.youtube.com domain. Changing SNI to anything other (even wxw.youtube.com) opens the website again.

#7

TLS filtering is done regardless of IP address.
Here’s how it looks from a server perspective:
youtube-tspu-server.zip (4.2 KB)

As you can see, the clients’ TLS ClientHello packet is received, but the ServerHello reply can’t be delivered. The client does not receive ServerHello. www.youtube.com does not work, www.nottube.com works.

NAT session teardown?

#8

Фильтр настроен на блокировку комбинации TLS Cipher Suites + Supported Groups + Signature Algorithms + SNI. Удаление какого-либо из шифра в любой части, изменение порядка cipher suites или любая другая модификация приводит к доставке пакета и работоспособности сетевой связности.

#9

А для чего именно может применяться такая настройка фильтра?

#10

@ValdikSS и снова я)
На операторе Tele2 только что заметил отвал newpipe, притом через браузер все нормально( даже www.youtube.com) открывается, твой тест парой постов выше тоже нормально проходит, хотя newpipe не пашет. Странно… Попробую запустить tcpdump

#11

Раз уже понятна схема блокировки, остался один вопрос: зачем так геморно и с таким паттерно? Почему нельзя просто заблочить по SNI? Или это специально для андроид клиента?

#12

Right now it seems like a TLS Fingerprinting to block an Android application which uses www.youtube.com as a domain fronting (wild guess: Navalny Android/iOS app?).

#13

Seems, NewPipe’s fingerprint is quite unique. https://tlsfingerprint.io/ does not parse Client Hello from aforementioned pcaps as known fingerprint that was already observed in the campus traffic.

#14

Its really useless to block NewPipe. Best candidate to block is Google’s Youtube app. Can it be something like tests or preparations for whole youtube block?

#15

I have no iOS devices, but Navalny’s app (ver. 2.0, one from Google Play Market) gives a different fingerprint on my Android:

image
image866×635 103 KB

Fingerprints https://tlsfingerprint.io/id/f0b2b996867b6380 and https://tlsfingerprint.io/id/f278257cdf4a43aa seem to be related, cetpmhjmdf-vizskfsved.global.ssl.fastly.net is Navalny-related domain (see https://archive.md/xgT57 for archived content).

#16

They use okhttp3 library with ConnectionSpec.MODERN_TLS.cipherSuites() and 2 additional ones click

// This will try to enable all modern CipherSuites(+2 more)
// that are supported on the device.
// Necessary because some servers (e.g. Framatube.org)
// don't support the old cipher suites.
// https://github.com/square/okhttp/issues/4053#issuecomment-402579554
final List<CipherSuite> cipherSuites =
        new ArrayList<>(ConnectionSpec.MODERN_TLS.cipherSuites());
cipherSuites.add(CipherSuite.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA);
cipherSuites.add(CipherSuite.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA);
final ConnectionSpec legacyTLS = new ConnectionSpec.Builder(ConnectionSpec.MODERN_TLS)
        .cipherSuites(cipherSuites.toArray(new CipherSuite[0]))
        .build();

builder.connectionSpecs(Arrays.asList(legacyTLS, ConnectionSpec.CLEARTEXT));

UPD

UPD: no, they use this cipher set only in this exact case, but in general they have a common okhttp3 cipher list (without 3DES, it is probably filtered by the tls library): https://github.com/square/okhttp/blob/06644bb0507873e9a3b89d9107da537f1b140e91/okhttp/src/main/java/okhttp3/ConnectionSpec.java#L68

#17

I’ve made a small modification in NewPipe by replacing TLS_RSA_WITH_AES_256_CBC_SHA with TLS_RSA_WITH_AES_128_CBC_SHA in the library cipher list, and the application is now working again.

#18

SmartTubeNext тоже перестал работать, по крайней мере, с теле2.

#19

UPD: no, they use this cipher set only in this exact case, but in general they have a common okhttp3 cipher list (without 3DES, it is probably filtered by the tls library): https://github.com/square/okhttp/blob/06644bb0507873e9a3b89d9107da537f1b140e91/okhttp/src/main/java/okhttp3/ConnectionSpec.java#L68

So they block HTTPS requests to www.youtube.com via okhttp library.

#20

Hint: this block could be circumvented by changing SNI case. wWw.youtube.com works.
Hint: other domains, such as docs.google.com, are not blocked with this TLS fingerprint.

#21

Фильтр убран. Что это такое было — непонятно, у меня нет даже предположений.