Merge pull request #9 from ditatompel/ditatompels/new-articles DPI & TCP Reset Attack

Ditatompels/new articles DPI & TCP Reset Attack

content/blog/new-stage-of-internet-censorship-in-indonesia-dpi-tcp-reset-attack/index.id.md

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+---
+title: "Babak Baru Sensor Internet di Indonesia: DPI & TCP Reset Attack"
+description: "Beberapa upstream provider atau checkpoint melakukan TCP Reset Attack untuk memblokir akses ke website-website yang dinilai ilegal."
+date: 2023-06-04T01:19:36+07:00
+lastmod:
+draft: false
+noindex: false
+featured: true
+pinned: false
+# comments: false
+series:
+#  - 
+categories:
+  - TIL
+  - Privasi 
+tags:
+  - MiTM
+  - Internet Positif
+  - VPN
+  - Proxy
+  - DNS-over-HTTPS
+  - Kominfo
+images:
+#  - 
+# menu:
+#   main:
+#     weight: 100
+#     params:
+#       icon:
+#         vendor: bs
+#         name: book
+#         color: '#e24d0e'
+authors:
+  - ditatompel
+---
+
+Berbeda dengan sebelumnya yang menggunakan **DNS filtering**, beberapa *upstream* telah melakukan **TCP Reset Attack** untuk memblokir akses ke website-website yang dinilai ilegal. Dan kenapa Anda harus mulai perduli untuk masalah ini.
+
+<!--more-->
+---
+
+## Latar Belakang
+Sejak beberapa bulan yang lalu, saya mulai tidak dapat mengakses **reddit.com** dari koneksi internet **ISP** saya, padahal di jaringan rumah saya sudah memakai **DNS-over-HTTPS (DoH)**. Hal yang sama terjadi juga ketika saya melakukan **VPN** ke server saya yang notabenenya tanpa **"Internet Positif"** (baca: tanpa sensor).
+
+Browser saya selalu mengatakan _error **"The connection was reset"**_. *Service* gratis [libreddit yang saya sediakan](https://libreddit.ditatompel.com/) untuk mengakses **Reddit** tanpa konten bermuatan **NSFW** juga menjadi tidak bekerja (servernya sebelumnya ada di **Indonesia Data Center Duren Tiga** atau **IDC-3D**).
+
+Setelah berdiskusi dengan rekan kantor dan melakukan sedikit observasi, saya dapat menyimpulkan bahwa yang saya alami adalah **_TCP reset attack_ (TCP RST)** dan terjadi di _**Upstream** provider_ / _network checkpoint_ yang saya gunakan. Sepertinya (menurut saya pribadi), *upstream provider* yang saya gunakan dipaksa atau terpaksa melakukan aktifitas *"jahat"* ini.
+
+Kenapa saya bilang terpaksa atau dipaksa? Karena *Upstream provider* adalah pelaku bisnis, dan tujuan bisnis salah satunya adalah meraih laba sebesar-besarnya. Sedangkan untuk melakukan **Deep Packet Inspection (DPI)** untuk *traffic* yang besar bukan hal yang murah. Coba saja cari informasi harga **Palo Alto 5200** series, **Cisco Firepower 9300** series, atau **FortiGate 6000** series jika tidak percaya. Itu baru biaya *hardware*, belum untuk biaya *maintenance*, dan pengeluaran oprasional seperti *training*, gaji, dan lain-lain. Tapi jika ancamannya adalah pencabutan izin, apa boleh buat?
+
+Memang perangkat *firewall enterprise* sekelas dengan yang saya sebutkan diatas pasti dimiliki perusahaan ISP besar, apa lagi di *network checkpoint*. Namun saya yakin, pelaku bisnis akan lebih memilih menghemat *resource* dan menghindari komplain dari *customer* bisnisnya (*downstream*) daripada harus melakukan *deployment* dan *integration* DPI di infrastruktur *network* yang sudah mereka punya.
+
+Jika *cost* untuk melakukan **DPI** akan sangat mahal, mungkinkah **TCP-RST attack** tersebut diimplementasikan di setiap *checkpoint* pada skala nasional? Tidak mungkin bukan? *Hold my beer*, Anda mungkin tidak tahu *track-record* seberapa *"kaya"* negara kita untuk membeli dan mengimplementasikan hal-hal seperti itu di bagian [#Privasi](#privasi).
+
+## Investigasi
+Saya melakukan investigasi yang sangat sederhana untuk membuktikan apakah benar **TCP-RST attack** itu secara otomatis terjadi. Ada 2 cara yang saya lakukan:
+1. menggunakan browser dengan *inspect element* (*simple*).
+2. Langsung dari server saya yang berada di Indonesia dan melakukan *network capture* menggunakan `tcpdump` (*advanced*).
+
+> _CATATAN: Dari yang selama ini saya amati, **TCP-RST attack** belum diimplementasikan di seluruh *checkpoint* / *upstream*. Jadi masih banyak provider yang belum terdampak._
+
+### Menggunakan Browser (*inspect element*, *simple*)
+![Browser error: connection reset](browser-connection-reset.png#center)
+
+Cara paling mudah (tetapi tidak detail) adalah menggunakan browser Anda. Ketika Anda tidak dapat mengakses reddit.com (atau situs lain yang diblokir pemerintah) dan mendapatkan pesan _error **"The connection was reset"**_; besar kemungkinan ISP (atau *upstream* ISP) Anda sudah mengimplementasikan metode ini.
+
+Cara lebih detail, sebelum mencoba akses ke reddit.com, *klik kanan* pada browser dan cari kata "*inspect*" atau "*developer tools*". Masuk ke tab "**Network**" kemudian baru coba akses reddit.com. Informasi "*CONNECTION_RESET*" pada kolom status muncul jika server mengirimkan *packet reset* (**RST**).
+
+### Menggunakan `tcpdump` dan `curl` (*advanced*)
+> Supaya dapat mengerti metode ini, Anda perlu mengetahui **konsep dasar TCP/IP** dan **3-Way-Handshake**. Saya pernah menulis mengenai analogi [TCP/IP - 3-Way-Handshake - MiTM - Session Hijacking]({{< ref "/blog/tcp-ip-3-way-handshake-mitm-session-hijacking/index.id" >}}) di tahun 2012 lalu. Atau silahkan mencari sendiri dari mesin penelusuran favorit Anda.
+
+Saya mencoba melakukan investigasi **langsung** dari server saya yang berada di **Indonesia Data Center Duren Tiga**. Caranya cukup *simple*, yaitu dengan mengirimkan **HTTP GET** ke reddit.com menggunakan `curl` dan melakukan *packet capture* menggunakan `tcpdump` secara bersamaan.
+
+Dibawah ini `151.101.xx.xxx` adalah salah 1 IP reddit.com yang saya dapatkan dari **DNS resolver** saat melakukan testing. Sedangkan `xxx.xxx.x06.26` adalah IP public server milik saya.
+
+Sample `curl https://reddit.com -vvv` output:
+```plain
+*   Trying 151.101.xx.xxx:443...
+* TCP_NODELAY set
+* Connected to reddit.com (151.101.xx.xxx) port 443 (#0)
+* ALPN, offering h2
+* ALPN, offering http/1.1
+* successfully set certificate verify locations:
+*   CAfile: /etc/ssl/certs/ca-certificates.crt
+  CApath: /etc/ssl/certs
+* TLSv1.3 (OUT), TLS handshake, Client hello (1):
+* OpenSSL SSL_connect: Connection reset by peer in connection to reddit.com:443 
+* Closing connection 0
+curl: (35) OpenSSL SSL_connect: Connection reset by peer in connection to reddit.com:443
+```
+
+sample `tcpdump -i ens18 dst 151.101.xx.xxx or src 151.101.xx.xxx -Nnn`:
+```plain
+tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
+listening on ens18, link-type EN10MB (Ethernet), capture size 262144 bytes
+00:54:25.646807 IP xxx.xxx.x06.26.43020 > 151.101.xx.xxx.443: Flags [S], seq 1624542501, win 64240, options [mss 1460,sackOK,TS val 3865742701 ecr 0,nop,wscale 7], length 0
+00:54:25.659369 IP 151.101.xx.xxx.443 > xxx.xxx.x06.26.43020: Flags [S.], seq 2720903651, ack 1624542502, win 65535, options [mss 1460,sackOK,TS val 1136396143 ecr 3865742701,nop,wscale 9], length 0
+00:54:25.659407 IP xxx.xxx.x06.26.43020 > 151.101.xx.xxx.443: Flags [.], ack 1, win 502, options [nop,nop,TS val 3865742714 ecr 1136396143], length 0
+00:54:25.666249 IP xxx.xxx.x06.26.43020 > 151.101.xx.xxx.443: Flags [P.], seq 1:518, ack 1, win 502, options [nop,nop,TS val 3865742721 ecr 1136396143], length 517
+00:54:25.666843 IP 151.101.xx.xxx.443 > xxx.xxx.x06.26.43020: Flags [R.], seq 1, ack 518, win 16, length 0
+00:54:25.666850 IP 151.101.xx.xxx.443 > xxx.xxx.x06.26.43020: Flags [R.], seq 1, ack 518, win 16, length 0
+00:54:25.666931 IP 151.101.xx.xxx.443 > xxx.xxx.x06.26.43020: Flags [R.], seq 1, ack 518, win 16, length 0
+00:54:25.678672 IP 151.101.xx.xxx.443 > xxx.xxx.x06.26.43020: Flags [.], ack 518, win 285, options [nop,nop,TS val 1136396162 ecr 3865742721], length 0
+00:54:25.678708 IP xxx.xxx.x06.26.43020 > 151.101.xx.xxx.443: Flags [R], seq 1624543019, win 0, length 0
+00:54:25.683731 IP 151.101.xx.xxx.443 > xxx.xxx.x06.26.43020: Flags [P.], seq 1:3717, ack 518, win 285, options [nop,nop,TS val 1136396167 ecr 3865742721], length 3716
+00:54:25.683753 IP xxx.xxx.x06.26.43020 > 151.101.xx.xxx.443: Flags [R], seq 1624543019, win 0, length 0
+```
+
+**Keterangan dari hasil `tcpdump` _flag_ diatas**:
+
+| TCP Flag  | tcpdump flag | keterangan        |
+| --------  | ------------ | ----------------- |
+| `SYN`     | `S`          | Koneksi dimulai   |
+| `FIN`     | `F`          | Koneksi selesai   |
+| **`RST`** | **`R`**      | **Koneksi reset** |
+| `PUSH`    | `P`          | Data *push*       |
+| `ACK`     | `.`          | *Acknowledgment*  |
+
+> _* Flag diatas dapat dikombinasikan, misalnya `[s.]` adalah packet `SYN-ACK`._
+
+![TCP-RST attack](tcp-rst-attack.png#center)
+
+Terlihat jelas setelah server melakukan *handshake* dan mengirimkan pengiriman *packet data*, saya langsung menerima `RST` (*reset*) *flag*.
+
+## Kenapa Anda Harus Perduli?
+Meskipun belum sekelas [The Great Firewall of China (GFW)](https://en.wikipedia.org/wiki/Great_Firewall), tetapi indikasi menuju kesana sangat terasa. yang sebelumnya hanya dari **DNS spoofing**, **filtering** dan **redirect**; sekarang sudah menggunakan **Deep Packet Inspection** dan **TCP reset attack**. 
+
+[Dikutip dari Wikipedia](https://en.wikipedia.org/wiki/Deep_packet_inspection#Indonesia), pemerintah Indonesia melalui **Telkom Indonesia** (ISP milik pemerintah) mengunakan teknologi **Deep Packet Inspection (DPI)** dari **Cisco Meraki** melakukan pengawasan (*surveillance*) dan *maping* Nomor Induk Kependudukan (**NIK**) terhadap masyarakat yang menggunakan jasa ISP milik pemerintah.
+
+Tujuan dari **Deep Packet Inspection (DPI)** termasuk melakukan *filter* terhadap konten pornografi, ujaran kebencian dan meredakan tensi (misalnya di Papua 2019). Pemerintah Indonesia juga berencana [meningkatkan pengawasan](wikipedia-dpi-indonesia.png#center) (*surveillance*) ke tingkat lebih lanjut hingga tahun 2030.
+
+### Makin Terbatasnya Akses Terhadap Informasi
+Kedepannya, ~~Anda~~ kita akan mengalami kesulitan untuk mendapatkan informasi yang dianggap *"terlarang"* oleh pemerintah. Ingin melihat dan mencoba sendiri contoh nyata-nya? Coba gunakan mesin pencari asal China bernama [Baidu](https://www.baidu.com/) dan lakukan pencarian dengan kata kunci **"Tiananmen Square"**. Bandingkan hasil penelusuran dari **Baidu** dengan hasil pencarian mesin pencari lain.
+
+Saya sendiri sudah mengalaminya, meskipun tidak seperti dan separah di China sana, tetapi sangat merepotkan dan menyebalkan. Misalnya ketika saya mencoba melakukan pencarian mengenai *trouble* yang saya alami mengenai masalah **IT**, sering kali mesin pencarian mengeluarkan hasil pencarian dari **Reddit** dan solusi itu ada dan sudah didiskusikan disana. Namun untuk mengaksesnya saya harus melakukan koneksi **VPN** ke server saya yang berada di luar Indonesia terlebih dahulu sebelum masuk ke *link* hasil pencarian tersebut.
+
+### Rusaknya Hak Asasi dan Turunnya Nilai-Nilai Demokrasi
+Pembatasan hak digital dapat merusak hak asasi manusia dan menurunkan nilai-nilai demokrasi. Contohnya pada awal tahun 2021, penduduk **desa Wadas** yang telah menolak proyek pertambangan batu Andesit (untuk keperluan proyek **Bendungan Bener**). Selama beberapa bulan kemudian, penduduk desa Wadas masih meluncurkan seri protes dan menggunakan media sosial untuk menggerakkan dukungan dan meningkatkan kesadaran. Namun, konektivitas internet mereka justru (diyakini) dibatasi oleh pihak berwajib sebagai respon terhadap protes warga pada Februari 2022.
+
+Penduduk Wadas melaporkan kesulitan dalam mengakses akun Twitter masing-masing pada minggu yang sama, walaupun belum jelas bagaimana pembatasan tersebut dilakukan. Siilahkan baca sendiri artikel dari DetiX berjudul [Derasnya Penindasan Hak Digital di Wadas](https://news.detik.com/x/detail/investigasi/20220221/Derasnya-Penindasan-Hak-Digital-di-Wadas/).
+
+### *Chilling Effect* / Efek Jera dan Matinya Kebebasan Berekspresi
+Efek jera atau biasa dikenal sebagai [*Chilling Effect*](https://en.wikipedia.org/wiki/Chilling_effect) adalah sebuah konsep ketakutan masyarakat yang muncul karena hukum atau peraturan perundang-undangan yang ambigu (*EHEMMMMM... UUITE.. Ehemmmm.. Maaf tiba-tiba batuk*). Biasanya *chilling effect* berhubungan dengan peraturan yang terkait dengan pencemaran nama baik atau fitnah (*Ehemmmm... maaf batuk lagi..*).
+
+Selama 2018, [polisi menangkap 122 orang terkait ujaran kebencian di media sosial](https://nasional.kompas.com/read/2019/02/15/15471281/selama-2018-polisi-tangkap-122-orang-terkait-ujaran-kebencian-di-medsos). Disana, ada lima jenis kejahatan, mulai dari *hoaks*, berita bohong, berita palsu, penistaan agama, hingga pencemaran nama baik ungkap **Brigjen Pol. Rachmad Wibowo** yang saat itu menjabat sebagai **Direktur Tindak Pidana Siber Badan Reserse Kriminal Polri**.
+
+Kemudian di 2021, dengan *"diaktifkannya"* **Polisi Siber** akan makin membungkam kebebasan sipil itu sendiri, khususnya tekait kebebasan berekspresi. Hal tersebut disampaikan oleh Koordinator Komisi untuk Orang Hilang dan Tindak Kekerasan (**Kontras**), **Fatia Maulidiyanti**.
+
+Dan di bulan februari 2022, hasil survey dari **Indikator Politik Indonesia** menunjukan bahwa 62,9% (dengan metode *stratified random* dari 1.200 responden dengan *margin of error* sekitar 2,9%) responden menyatakan setuju dan sangat setuju bahwa [masyarakat saat ini semakin takut dalam mengeluarkan pendapat](https://nasional.tempo.co/read/1580168/survei-indikator-politik-indonesia-629-persen-rakyat-semakin-takut-berpendapat).
+
+> "_Sekarang Polisi Siber itu gampang sekali, kalau misalnya Anda mendapatkan berita yang mengerikan, lalu lapor ke polisi, dalam waktu sekian menit diketahui dapat dari siapa, dari mana, lalu ditemukan pelakunya lalu ditangkap." - **Mahfud MD**_
+
+### Privasi
+Sebenarnya, privasi adalah hal pertama yang seharusnya saya sebut dari semua poin-poin ini. Tapi karena di Indonesia masyarakatnya masih tidak begitu perduli urusan privasi ya saya taruh di hampir akhir. *Lha wong* data **BSI** bocor aja yang paling banyak diributin duitnya, bukan kebocoran data pribadinya.
+
+> _Tenang boss, duit itu pasti balik karena perbankan pasti punya rekap data dan backup, transaksi sesama bank maupun antar bank juga pasti tercatat. Yang rugi adalah waktu dan tenaga Anda saat layanan tersebut tidak bisa digunakan. Dan yang paling penting, data pribadi Anda yang nantinya diperjual belikan._
+
+Kembali ke masalah privasi dan **Deep Packet Inspection (DPI)**, sebenarnya awal DPI dibuat oleh *engineer* adalah untuk mengukur dan mengatur keamanan jaringan dan melindungi pengguna dan mencegah penyebaran *malware*. Tapi, dengan dimanfaatkan teknologi tersebut sebagai alat *surveillance* akan sangat berdampak buruk pada privasi ~~Anda~~ kita. Selain itu, DPI juga dapat dimanfaatkan untuk mempelajari prilaku / *interest* seorang individu maupun instansi dari aktifitas mereka di internet yang pada akhirnya dapat digunakan untuk *targeted (behavioral) marketing*. 
+
+Berbagai laporan telah mengaitkan pihak berwajib dengan pembelian dan penggunaan *spyware* dan alat-alat *surveillance* canggih lainnya. Misalnya, di tahun 2015, **Citizen Lab**; sebuah kelompok penelitian yang berbasis di **Toronto** [menduga bahwa pemerintah Indonesia pernah menggunakan *spyware* **FinFisher**](https://citizenlab.ca/2015/10/mapping-finfishers-continuing-proliferation/) yang mengumpulkan data seperti audio **Skype**, *key log*, dan tangkapan layar.
+
+Di tahun 2016, [**Joseph Cox**](https://www.vice.com/en/contributor/joseph-cox) [mengungkap](https://www.vice.com/en/article/4xaq4m/the-uk-companies-exporting-interception-tech-around-the-world) bahwa *International Mobile Subscriber Identity-catchers* ([**IMSI-catchers**](https://en.wikipedia.org/wiki/IMSI-catcher)) pernah dijual ke Indonesia dari perusahaan Swiss dan Inggris. **IMSI-catcher** adalah perangkat yang digunakan untuk menangkap (*intercept*) *traffic* jaringan ponsel dan melakukan pelacakan lokasi kepada pengguna ponsel. Bisa dibilang, seperti sebuah *"BTS palsu"* sebagai perantara antara ponsel milik pengguna ke BTS asli milik ISP.
+
+Pada Desember 2021, **Citizen Lab**, menyatakan bahwa ada kemungkinan besar pemerintah Indonesia telah menjadi pelanggan **Cytrox** yang menjual **Predator** *spyware*. Selain itu, **Citizen Lab** juga melaporkan pada Desember 2020 bahwa Indonesia sangat mungkin pernah membeli teknologi dari [**Circles**](https://dimse.info/circles/), sebuah perusahaan yang menjual *exploit* dari sistem selular global yang kemudian bergabung dengan [NSO group](https://www.nsogroup.com/). Metode yang dilakukan **Citizen Lab** untuk mengetahui hal tersebut adalah dengan melakukan *scanning & signature fingerprinting* terhadap *checkpoint firewall* pada perangkat **Circles** melalui layanan [Shodan](https://www.shodan.io/).
+
+### Dampak Terhadap Perekonomian
+Dari yang saya amati sampai saat ini, implementasi **TCP-RST attack** masih ada di beberapa *upstream provider* saja. Namun jika hal ini ini terus dilakukan dan diimplementasikan di seluruh *checkpoint* yang keluar dari Indonesia, maka akan berdampak pada minat beli dan investasi ke *Cloud Provider* / *Datacenter* yang berlokasi di Indonesia.
+
+Siapa yang mau jika tiba-tiba *microservices*-nya tidak berfungsi karena **TCP-RST attack** tersebut? Saya sendiri mulai memindahkan VPS-VPS saya ke luar Indonesia karena menurut saya, infrastruktur *server* / *cloud* seharusnya tidak (secara tiba-tiba) dibatasi (tanpa pemberitahuan sebelumnya) untuk mengakses data yang sudah tersedia di *public* / *public API*.
+
+![Moving to AWS](moving-to-aws.png#center)
+
+## Menghindari sensor
+Untuk melakukan *bypass* pemblokiran yang berbasis **DNS** seperti **DNS spoofing**, **DNS filtering** dan **DNS redirect**; mengajari orang *awam* memanfaatkan **DNS-over-HTTPS (DoH)** masih cukup mudah. Tetapi untuk melakukan *bypass* DPI dan **TCP RST attack**, saya rasa akan sangat sulit dan mustahil dilakukan oleh mayoritas orang awam (secara teknologi) di Indonesia.
+
+Salah satu cara adalah menggunakan *tunnel* ke *server* yang berada diluar Indonesia, entah itu **VPN** atau **SOCKS5 proxy**. Itu pun pemerintah dan ISP yang Anda gunakan akan tetap tahu bahwa Anda menggunakan **Proxy** / **VPN**. Bedanya mereka hanya tahu Anda melakukan koneksi VPN / Proxy server dan dimana VPN / Proxy server tersebut berada. Selebihnya mereka tidak tahu (hanya Anda, VPN / Server / Proxy *provider* yang tahu *service* dan *host** mana Anda berkomunikasi).
+
+Jika Anda benar-benar *concern* terhadap privasi, pemilihan **VPN provider** juga harus dilakukan dengan riset yang cukup rumit. Banyak sekali aplikasi di **App Store** yang menawarkan **VPN gratis**, tetapi tidak sedikit **VPN provider** yang pada akhirnya mengolah dan menjual data Anda.
+
+Kita juga berharap bahwa teknologi **QUIC/HTTP3** segera masuk ke babak baru yang **"mungkin"** akan sedikit membantu mengurangi dampak **TCP RST attack**.
+
+## Sumber dan Referensi
+- "[Indonesia: Freedom on the Net 2022 Country Report](https://freedomhouse.org/country/indonesia/freedom-net/2022)" - freedomhouse.org.
+- "[State of Privacy Indonesia](https://privacyinternational.org/state-privacy/1003/state-privacy-indonesia)" - privacyinternational.org.
+- NetBlocks. 2019b: "[Internet disrupted in Papua, Indonesia amid protests and calls for independence](https://netblocks.org/reports/internet-disrupted-in-papua-indonesia-amid-mass-protests-and-calls-for-independence-eBOgrDBZ)" - netblocks.org.
+- Thompson, Nik; McGill, Tanya; and Vero Khristianto, Daniel, "[Public Acceptance of Internet Censorship in Indonesia](https://aisel.aisnet.org/acis2021/22)" (2021). ACIS 2021 Proceedings. 22.
+- Wildana, F. (2021) "[An Explorative Study on Social Media Blocking in Indonesia](https://journal.unesa.ac.id/index.php/jsm/article/view/12976)", The Journal of Society and Media, 5(2), pp. 456–484. doi: 10.26740/jsm.v5n2.p456-484.
+-  Paterson, Thomas (4 May 2019). "[Indonesian cyberspace expansion: a double-edged sword](https://doi.org/10.1080%2F23738871.2019.1627476)". *Journal of Cyber Policy*. 4 (2): 216–234. doi:10.1080/23738871.2019.1627476. ISSN 2373-8871. S2CID 197825581.
+- Bill Marczak, John Scott-Railton, Bahr Abdul Razzak, Noura Al-Jizawi, Siena Anstis, Kristin Berdan, and Ron Deibert, "[Pegasus vs. Predator: Dissident’s Doubly-Infected iPhone Reveals Cytrox Mercenary Spyware](https://citizenlab.ca/2021/12/pegasus-vs-predator-dissidents-doubly-infected-iphone-reveals-cytrox-mercenary-spyware/)" - citizenlab.ca.
+- Bill Marczak, John Scott-Railton, Siddharth Prakash Rao, Siena Anstis, and Ron Deibert, "[Running in Circles
+Uncovering the Clients of Cyberespionage Firm Circles](https://citizenlab.ca/2020/12/running-in-circles-uncovering-the-clients-of-cyberespionage-firm-circles/)" - citizenlab.ca.
+- Bill Marczak, John Scott-Railton, Adam Senft, Irene Poetranto, and Sarah McKune, "[Pay No Attention to the Server Behind the Proxy](https://citizenlab.ca/2015/10/mapping-finfishers-continuing-proliferation/)", Mapping FinFisher’s Continuing Proliferation - citizenlab.ca.
+- Joseph Cox, "[British Companies Are Selling Advanced Spy Tech to Authoritarian Regimes](https://www.vice.com/en/article/4xaq4m/the-uk-companies-exporting-interception-tech-around-the-world)" - vice.com.
+- Thomas Brewster, "[A Multimillionaire Surveillance Dealer Steps Out Of The Shadows and His $9 Million WhatsApp Hacking Van](https://www.forbes.com/sites/thomasbrewster/2019/08/05/a-multimillionaire-surveillance-dealer-steps-out-of-the-shadows-and-his-9-million-whatsapp-hacking-van/)" - forbes.com.
+- Moh. Khory Alfarizi, Febriyan, "[Survei Indikator Politik Indonesia: 62,9 Persen Rakyat Semakin Takut Berpendapat](https://nasional.tempo.co/read/1580168/survei-indikator-politik-indonesia-629-persen-rakyat-semakin-takut-berpendapat)" - tempo.co .
+- Abba Gabrillin, Krisiandi, "[Selama 2018, Polisi Tangkap 122 Orang Terkait Ujaran Kebencian di Medsos](https://nasional.kompas.com/read/2019/02/15/15471281/selama-2018-polisi-tangkap-122-orang-terkait-ujaran-kebencian-di-medsos)" - kompas.com.
+- Tsarina Maharani, Dani Prabowo "[Kontras: Polisi Siber yang Akan Diaktifkan Pemerintah Berpotensi Bungkam Kebebasan Berekspresi](https://nasional.kompas.com/read/2020/12/28/14074121/kontras-polisi-siber-yang-akan-diaktifkan-pemerintah-berpotensi-bungkam)" - kompas.com.

content/blog/new-stage-of-internet-censorship-in-indonesia-dpi-tcp-reset-attack/index.md

@@ -0,0 +1,191 @@
+---
+title: "New Stage of Internet Censorship in Indonesia: DPI & TCP Reset Attack"
+description: "Beberapa upstream provider atau checkpoint melakukan TCP Reset Attack untuk memblokir akses ke website-website yang dinilai ilegal."
+date: 2023-06-04T01:19:36+07:00
+lastmod:
+draft: false
+noindex: false
+featured: false
+pinned: false
+# comments: false
+series:
+#  - 
+categories:
+  - TIL
+  - Privacy
+tags:
+  - MiTM
+  - VPN
+  - Proxy
+  - DNS-over-HTTPS
+images:
+#  - 
+# menu:
+#   main:
+#     weight: 100
+#     params:
+#       icon:
+#         vendor: bs
+#         name: book
+#         color: '#e24d0e'
+authors:
+  - ditatompel
+---
+
+Unlike before that using **DNS filtering**, several *upstreams* have performed a **TCP Reset Attack** to block access to websites that are considered illegal. And why you (especially Indonesian) should care for this mess.
+
+<!--more-->
+---
+
+## Background
+A few months ago, I started facing problems when trying to access **reddit.com** from my home connection, even though all devices in my home network already use **DNS-over-HTTPS (DoH)**. The same thing happened even I route all my traffic to my server located in **Indonesia Data Center** using _**VPN** tunnel_.
+
+My browser always shows **_"The connection was reset"_** error message when I try to access reddit.com. [My libreddit service](https://libreddit.ditatompel.com/) that I provided to access **Reddit** without **NSFW** contents stopped working (Previous server location: **Indonesia Data Center Duren Tiga** or **IDC-3D**).
+
+After discussing with colleagues and make some observations, I'm sure that I'm become a victim of **TCP reset attack (TCP RST)** and it happened at the *upstream provider* / *network checkpoint* that I used. It seems (in my personal opinion), my *upstream provider*  is *"forced"* to carry out this *"evil"* activity.
+
+Why do I say *"forced"*? Because most *upstream providers* are typically business oriented, and one of the their business goals is to get the maximum profit. Meanwhile, doing **Deep Packet Inspection (DPI)** for large amount of traffic is not cheap. Just search for the price of **Palo Alto 5200** series, **Cisco Firepower 9300** series, or **FortiGate 6000** series if you did not believe in me. That's just hardware costs, not for maintenance costs, and operational expenses such as training, salaries, and others.
+
+I'm aware that *enterprise firewall* devices like the ones I mentioned above must be owned by large ISP companies, especially at *network checkpoints*. But I'm sure, business people will prefer to save *resources* and avoid complaints from their customers (*downstream*) rather than to *deploy* and *integrate* DPI in their network infrastructure they already run.
+
+If the cost of doing **DPI** will be very expensive, is it possible that the **TCP-RST attack** is implemented at every *checkpoint* on a national scale? It just impossible, right? *Hold my beer*, read how *"rich"* our country is to buy and implement such things in [#Privacy](#privacy) section.
+
+## Investigation
+I did a very simple investigation to prove whether it was true that **TCP-RST attack** was automatically performed. There are 2 things that I do:
+1. Simply use my browser's *inspect element* feature (*simple*).
+2. Directly check from my server in Indonesia and do network capture using `tcpdump` (*advanced*).
+
+> _NOTE: From what I have observed, **TCP-RST attack** has not been implemented in all *checkpoint* / *upstream*. So there are still many providers who have not been affected._
+
+### Using browser's *inspect element* feature (*simple*)
+![Browser error: connection reset](browser-connection-reset.png#center)
+
+The easiest (but less detail) way is to use your browser. When you can't access reddit.com (or any other government-blocked site) and get **_"The connection was reset"_** error message; most likely your ISP (or *upstream* ISP) already implemented this method.
+
+In a more detailed way, before trying to access reddit.com, *right-click* on your browser and look for something like  "*inspect*" or "*developer tools*". Go to the "**Network**" tab and try to access reddit.com. The "*CONNECTION_RESET*" information message in the *status* column appears when the server sends *packet reset* (**RST**).
+
+### Using `tcpdump` and `curl` (*advanced*)
+> In order to understand this method, you need to know **basic concepts of TCP/IP** and [**3-Way-Handshake**](https://en.wikipedia.org/wiki/Handshake_(computing)#TCP_three-way_handshake).
+
+I tried to do a direct investigation from my server which is at **Indonesia Data Center Duren Tiga**. The method is quite *simple*, by sending **HTTP GET** using `curl` to reddit.com and do packet capture using `tcpdump` simultaneously.
+
+Below, `151.101.xx.xxx` is one of the reddit.com IPs that I got from **DNS resolver** when doing testing, and `xxx.xxx.x06.26` is my server public IP.
+
+Sample `curl https://reddit.com -vvv` output:
+```plain
+*   Trying 151.101.xx.xxx:443...
+* TCP_NODELAY set
+* Connected to reddit.com (151.101.xx.xxx) port 443 (#0)
+* ALPN, offering h2
+* ALPN, offering http/1.1
+* successfully set certificate verify locations:
+*   CAfile: /etc/ssl/certs/ca-certificates.crt
+  CApath: /etc/ssl/certs
+* TLSv1.3 (OUT), TLS handshake, Client hello (1):
+* OpenSSL SSL_connect: Connection reset by peer in connection to reddit.com:443 
+* Closing connection 0
+curl: (35) OpenSSL SSL_connect: Connection reset by peer in connection to reddit.com:443
+```
+
+sample `tcpdump -i ens18 dst 151.101.xx.xxx or src 151.101.xx.xxx -Nnn` output:
+```plain
+tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
+listening on ens18, link-type EN10MB (Ethernet), capture size 262144 bytes
+00:54:25.646807 IP xxx.xxx.x06.26.43020 > 151.101.xx.xxx.443: Flags [S], seq 1624542501, win 64240, options [mss 1460,sackOK,TS val 3865742701 ecr 0,nop,wscale 7], length 0
+00:54:25.659369 IP 151.101.xx.xxx.443 > xxx.xxx.x06.26.43020: Flags [S.], seq 2720903651, ack 1624542502, win 65535, options [mss 1460,sackOK,TS val 1136396143 ecr 3865742701,nop,wscale 9], length 0
+00:54:25.659407 IP xxx.xxx.x06.26.43020 > 151.101.xx.xxx.443: Flags [.], ack 1, win 502, options [nop,nop,TS val 3865742714 ecr 1136396143], length 0
+00:54:25.666249 IP xxx.xxx.x06.26.43020 > 151.101.xx.xxx.443: Flags [P.], seq 1:518, ack 1, win 502, options [nop,nop,TS val 3865742721 ecr 1136396143], length 517
+00:54:25.666843 IP 151.101.xx.xxx.443 > xxx.xxx.x06.26.43020: Flags [R.], seq 1, ack 518, win 16, length 0
+00:54:25.666850 IP 151.101.xx.xxx.443 > xxx.xxx.x06.26.43020: Flags [R.], seq 1, ack 518, win 16, length 0
+00:54:25.666931 IP 151.101.xx.xxx.443 > xxx.xxx.x06.26.43020: Flags [R.], seq 1, ack 518, win 16, length 0
+00:54:25.678672 IP 151.101.xx.xxx.443 > xxx.xxx.x06.26.43020: Flags [.], ack 518, win 285, options [nop,nop,TS val 1136396162 ecr 3865742721], length 0
+00:54:25.678708 IP xxx.xxx.x06.26.43020 > 151.101.xx.xxx.443: Flags [R], seq 1624543019, win 0, length 0
+00:54:25.683731 IP 151.101.xx.xxx.443 > xxx.xxx.x06.26.43020: Flags [P.], seq 1:3717, ack 518, win 285, options [nop,nop,TS val 1136396167 ecr 3865742721], length 3716
+00:54:25.683753 IP xxx.xxx.x06.26.43020 > 151.101.xx.xxx.443: Flags [R], seq 1624543019, win 0, length 0
+```
+
+**Note from the `tcpdump` _flag_ result above**:
+
+| TCP Flag  | tcpdump flag | Description          |
+| --------  | ------------ | -------------------- |
+| `SYN`     | `S`          | Connection start     |
+| `FIN`     | `F`          | Connection end       |
+| **`RST`** | **`R`**      | **Connection reset** |
+| `PUSH`    | `P`          | Data *push*          |
+| `ACK`     | `.`          | *Acknowledgment*     |
+
+> _* Flag may be combined, for example `[s.]` is `SYN-ACK` packet._
+
+![TCP-RST attack](tcp-rst-attack.png#center)
+
+It is clear that after *handshakes* and first *data packet* was sent from my server, I immediately receive a `RST` (*reset*) *flag*.
+
+## Why you should care?
+Even though it is not (yet) in the same class as [The Great Firewall of China (GFW)](https://en.wikipedia.org/wiki/Great_Firewall), the indications *going to be there* are very high. The previous method were just **DNS spoofing**, **DNS Filtering** and **DNS Redirect**; but now using *Deep Packet Inspection* and *TCP reset attack* which impossible for majority *non-tech* in Indonesia to *bypass*.
+
+[Quoted from Wikipedia](https://en.wikipedia.org/wiki/Deep_packet_inspection#Indonesia), the Indonesian government through **Telkom Indonesia** (government-owned ISP) supported by **Cisco Meraki** **DPI** technology perform country-wide surveillance by the way of *Deep Packet Inspection* and *map* National Identity Number (**NIK**) of its citizens that registered to the state-owned ISP.
+
+The purpose of **Deep Packet Inspection (DPI)** includes *filtering* pornographic content, hate speech and reducing tension (for example in Papua 2019). Indonesian government also plans to [scale up the surveillance](wikipedia-dpi-indonesia.png#center) to the next level until 2030.
+
+### Increasingly limited access to information
+In the future, obtaining information that is considered *"forbidden"* by the government will be very difficult. Want to see and try the real examples by yourself? Try using a search engine from China called [Baidu](https://www.baidu.com/) and do a search with **"Tiananmen Square"** keyword. Compare search results from **Baidu** with other search engines results.
+
+I've experienced it myself, although it's not like and as bad as in China, but it's very inconvenient and annoying. For example, when I try to search something related to **IT** problems, Reddit discussion usually appears on search engine results, the solution was there (or at least, link to the solution was there). But to access it, I have to route all my laptop internet traffic to my VPN server (outside Indonesia) first before entering the reddit link page of the search results.
+
+### Damage to human rights and democratic values
+Restrictions on digital rights can undermine human rights and reduce democratic values. For example, at the beginning of 2021, residents of **desa Wadas** who had rejected the Andesite stone mining project (for the purposes of the **Bendungan Bener** project). Over the next few monts, residents of *desa Wadas* are still launched a series of protests and using social media as online mobilization tools and raise awareness. However, their internet connectivity was (believed to be) restricted by the authorities in response to citizen protests in February 2022.
+
+*Wadas* protesters reported difficulty accessing their Twitter accounts that same week, though it remains unclear how authorities limiting their access to their own Twitter accounts. Read more complete article from **DetikX**: "[*Derasnya Penindasan Hak Digital di Wadas*](https://news.detik.com/x/detail/investigasi/20220221/Derasnya-Penindasan-Hak-Digital-di-Wadas/)" written in Bahasa Indonesia.
+
+### *Chilling Effect* and the death of freedom of expression
+[*Chilling Effect*](https://en.wikipedia.org/wiki/Chilling_effect) is a concept of public fear that arises due to ambiguous laws or regulations (*EHEMMMMM... [UUITE](https://en.wikipedia.org/wiki/Internet_censorship_in_Indonesia#ITE_Law).. Ehemmmm.. Sorry for coughing suddenly*). In Indonesia *chilling effect* usually is related defamation or hate speech (*Ehemmm... sorry cough again..*).
+
+During 2018, [police arrested 122 people for hate speech on social media](https://nasional.kompas.com/read/2019/02/15/15471281/selama-2018-polisi-tangkap-122-orang-terkait-ujaran-kebencian-di-medsos) (written in Bahasa Indonesia). There are five types of crimes, ranging from *hoaxes*, fake news, blasphemy, to defamation said **Brigjen Pol. Rachmad Wibowo** who at that time served as **Direktur Tindak Pidana Siber Badan Reserse Kriminal Polri** (*Director of cyber crime at the [Indonesian National Police](https://en.wikipedia.org/wiki/Indonesian_National_Police)'s criminal investigation agency*).
+
+Then in 2021, the *"activation"* of [**Indonesia Cyber Police**](https://cfds.fisipol.ugm.ac.id/2021/02/05/the-existence-of-indonesia-cyber-police-what-does-it-mean-for-us-netizens/) drive civils to increasingly practice [self-censorship](https://en.wikipedia.org/wiki/Self-censorship), especially regarding [freedom of speech](https://en.wikipedia.org/wiki/Freedom_of_speech). That statement was conveyed by the Coordinator of **Komisi untuk Orang Hilang dan Tindak Kekerasan**  (**Kontras**, the *Commission for Missing Persons and Acts of Violence*), **Fatia Maulidiyanti**.
+
+And in February 2022, the survey results from **Indikator Politik Indonesia** showed that 62.9% (using the *stratified random* method out of 1,200 respondents with a *margin of error* of around 2.9%) respondents agreed and strongly agreed that [the public is now increasingly afraid of expressing opinions](https://nasional.tempo.co/read/1580168/survei-indikator-politik-indonesia-629-persen-rakyat-semakin-takut-berpendapat) (written in Bahasa Indonesia).
+
+> _"If (for example) you get terrible (fake) news, then report it to the police, in a few minutes it will be known from whom, where from, then the culprit is found and then arrested." - **Mahfud MD**_
+
+### Privacy
+Actually, **Deep Packet Inspection** was initially created to measure and manage network security and protect users and prevent the spread of *malware*. However, using this technology as a surveillance tool will have a very bad impact on ~~your~~ our privacy. In addition, DPI can also be used to study the behavior or *interest* of an individual or institution from their activities on the internet which can be used for *targeted (behavioral) marketing*.
+
+Various reports have linked authorities with the purchase and use of *spyware* and other sophisticated *surveillance* tools. For example, in 2015, **Citizen Lab**; a research group based in **Toronto** [alleges that the Indonesian government use **FinFisher** *spyware*](https://citizenlab.ca/2015/10/mapping-finfishers-continuing-proliferation) which collects data such as **Skype** audio, *key log*, and screenshots.
+
+In 2016, [**Joseph Cox**](https://www.vice.com/en/contributor/joseph-cox) [revealed](https://www.vice.com/en/article/4xaq4m/the-uk-companies-exporting-interception-tech-around-the-world) that **International Mobile Subscriber Identity-catchers** ([**IMSI-catchers**](https://en.wikipedia.org/wiki/IMSI-catcher)) was sold to Indonesia from Switzerland and British companies. **IMSI-catcher** is a device used to intercept traffic of cellphone networks and track the location of cellphone users. You could say, it's like a *"fake BTS"* as an intermediary between the user's cellphone and the ISP's original BTS.
+
+In December 2021, **Citizen Lab**, stated that there was a high probability that the Indonesian government had become a **Cytrox** (selling **Predator Spyware**) customer. In addition, **Citizen Lab** also reported in December 2020 that Indonesia is very likely to have purchased technology from [**Circles**](https://dimse.info/circles/), a company that sells exploits of global cellular systems who later joined the [NSO group](https://www.nsogroup.com/). The method used by **Citizen Lab** to find out their report is by doing *scanning & signature fingerprinting* of *firewall checkpoint* on **Circles** devices through [Shodan](https://www.shodan.io/) service.
+
+### Economic impact
+So far (from what I have observed), **TCP-RST attack** implementations still only exist in several *upstream providers / checkpoints*. However, if this continues to be carried out and implemented in all *checkpoints* that leaving Indonesia (*outbound traffic*), then it will definitely have an impact on buying interest for *Cloud Provider* / *Datacenter* located in Indonesia.
+
+Who wants their *microservices* suddenly stopped working because of this **TCP-RST attack**? I started moving my VPSes somewhere outside Indonesia, because in my opinion, server / cloud infrastructures should not be (suddenly) restricted (without prior notification) to access public data or APIs.
+
+![Moving to AWS](moving-to-aws.png#center)
+
+## Evading censorship
+To *bypass* **DNS** based censorship such as **DNS spoofing**, **DNS filtering** and **DNS redirect**; teaching *non-tech* people to use **DNS-over-HTTPS (DoH)** is quite easy. But to *bypass* **DPI** and **TCP RST attack** would be very difficult and impossible for majority *non-tech* people in Indonesia to do.
+
+A few way to avoid censorship is use *network tunnel* to a *server* outside Indonesia, whether it's **VPN** or **SOCKS5 proxy**. Even then, the government and the ISP you use will still know that you are using a **Proxy** / **VPN**. The difference is: they only know that you are connecting to VPN / SOCKS5 servers and where the VPN / SOCKS5 server is located. Other than that, the don't know anything (only you and VPN / Server / Proxy provider know what service / host you communicate with).
+
+If you are really *concern* about privacy, choosing a **VPN provider** must also be done with quite complicated research. Lots of apps on the **App Store** offer **free VPN**, but most of them end up with selling your data.
+
+And I hope, **QUIC/HTTP3** technology will enter a new chapter soon that *"may"* help us mitigate the impact of **TCP RST attack** a bit.
+
+## Sources and references
+- "[Indonesia: Freedom on the Net 2022 Country Report](https://freedomhouse.org/country/indonesia/freedom-net/2022)" - freedomhouse.org.
+- "[State of Privacy Indonesia](https://privacyinternational.org/state-privacy/1003/state-privacy-indonesia)" - privacyinternational.org.
+- NetBlocks. 2019b: "[Internet disrupted in Papua, Indonesia amid protests and calls for independence](https://netblocks.org/reports/internet-disrupted-in-papua-indonesia-amid-mass-protests-and-calls-for-independence-eBOgrDBZ)" - netblocks.org.
+- Thompson, Nik; McGill, Tanya; and Vero Khristianto, Daniel, "[Public Acceptance of Internet Censorship in Indonesia](https://aisel.aisnet.org/acis2021/22)" (2021). ACIS 2021 Proceedings. 22.
+- Wildana, F. (2021) "[An Explorative Study on Social Media Blocking in Indonesia](https://journal.unesa.ac.id/index.php/jsm/article/view/12976)", The Journal of Society and Media, 5(2), pp. 456–484. doi: 10.26740/jsm.v5n2.p456-484.
+-  Paterson, Thomas (4 May 2019). "[Indonesian cyberspace expansion: a double-edged sword](https://doi.org/10.1080%2F23738871.2019.1627476)". *Journal of Cyber Policy*. 4 (2): 216–234. doi:10.1080/23738871.2019.1627476. ISSN 2373-8871. S2CID 197825581.
+- Bill Marczak, John Scott-Railton, Bahr Abdul Razzak, Noura Al-Jizawi, Siena Anstis, Kristin Berdan, and Ron Deibert, "[Pegasus vs. Predator: Dissident’s Doubly-Infected iPhone Reveals Cytrox Mercenary Spyware](https://citizenlab.ca/2021/12/pegasus-vs-predator-dissidents-doubly-infected-iphone-reveals-cytrox-mercenary-spyware/)" - citizenlab.ca.
+- Bill Marczak, John Scott-Railton, Siddharth Prakash Rao, Siena Anstis, and Ron Deibert, "[Running in Circles
+Uncovering the Clients of Cyberespionage Firm Circles](https://citizenlab.ca/2020/12/running-in-circles-uncovering-the-clients-of-cyberespionage-firm-circles/)" - citizenlab.ca.
+- Bill Marczak, John Scott-Railton, Adam Senft, Irene Poetranto, and Sarah McKune, "[Pay No Attention to the Server Behind the Proxy](https://citizenlab.ca/2015/10/mapping-finfishers-continuing-proliferation/)", Mapping FinFisher’s Continuing Proliferation - citizenlab.ca.
+- Joseph Cox, "[British Companies Are Selling Advanced Spy Tech to Authoritarian Regimes](https://www.vice.com/en/article/4xaq4m/the-uk-companies-exporting-interception-tech-around-the-world)" - vice.com.
+- Thomas Brewster, "[A Multimillionaire Surveillance Dealer Steps Out Of The Shadows and His $9 Million WhatsApp Hacking Van](https://www.forbes.com/sites/thomasbrewster/2019/08/05/a-multimillionaire-surveillance-dealer-steps-out-of-the-shadows-and-his-9-million-whatsapp-hacking-van/)" - forbes.com.
+- Moh. Khory Alfarizi, Febriyan, "[Survei Indikator Politik Indonesia: 62,9 Persen Rakyat Semakin Takut Berpendapat](https://nasional.tempo.co/read/1580168/survei-indikator-politik-indonesia-629-persen-rakyat-semakin-takut-berpendapat)" - tempo.co .
+- Abba Gabrillin, Krisiandi, "[Selama 2018, Polisi Tangkap 122 Orang Terkait Ujaran Kebencian di Medsos](https://nasional.kompas.com/read/2019/02/15/15471281/selama-2018-polisi-tangkap-122-orang-terkait-ujaran-kebencian-di-medsos)" - kompas.com.
+- Tsarina Maharani, Dani Prabowo "[Kontras: Polisi Siber yang Akan Diaktifkan Pemerintah Berpotensi Bungkam Kebebasan Berekspresi](https://nasional.kompas.com/read/2020/12/28/14074121/kontras-polisi-siber-yang-akan-diaktifkan-pemerintah-berpotensi-bungkam)" - kompas.com.