Understanding DNS with ActionDispatch::HostAuthorization

2020 年 10 月 3 日開催の、Kaigi on Rails で発表した内容です。（発表時間 20 分）

## 2020/10/12 追記
このスライドの説明だけですと攻撃の特性がわかりづらかったので、個人ブログの以下の記事にて追加の説明を行いました。
https://yucao24hours.me/blog/2020/10/12/dns-rebindig-basics-revised/

Transcript

1. ,BJHJ
   PO
   3BJMT
   
   QSFTFOUFE
   CZ
   ZVDBPIPVST ActionDispatch::HostAuthorization DNS ͱֶͿ ͷ͠ ͘ Έ Photo by Gauravdeep Singh Bansal on Unsplash
2. 2 Ӭ࿨γεςϜϚωδϝϯτ
   ΞδϟΠϧࣄۀ෦ॴଐ
   3BJMT
   Λ࢖ͬͨ࢓ࣄɺΞδϟΠϧͳ։ൃ͕ಘҙͰ޷͖
   ޷͖ͳݘछ͸
   γϕϦΞϯɾϋεΩʔ
   δϟʔϚϯɾγΣύʔυ
   ຊ೔ͷൃද΁ͷϑΟʔυόοΫΛ͓଴͍ͪͯ͠·͢ʂ
   Hello, I’m… yucao24hours
6. 6 ਆాਢాொํ໘͔Β͖·ͨ͠ ʁ ˞
   Ӭ࿨γεςϜϚωδϝϯτ౦ژࢧࣾ͸ਆాਢాொʹҐஔ͍ͯ͠·͢ Distinguished Engineer 5%%
   XJUI
   HJU
 -POH
   MJWF
   FOHJOFFSJOH Koichi ITO Super duper wakamono ίʔυϨϏϡʔຊϊοΫͰ
   ֶΜͩ
   3BJMT
   ϦϑΝΫλϦϯά 9sako6 Me "DUJPO%JTQBUDI)PTU"VUIPSJ[BUJPO
   ͱֶͿ
   %/4
   ͷ͘͠Έ yucao24hours A Living Legend a_matsuda DPNJOH
   TPPO
7. 7 ຊ೔͓࿩͢͠Δ͜ͱ  %/4
   ͷ͖΄Μ
   • %/4
   ͱ͸ͳʹ͔
   • ໰͍߹Θͤޮ཰ԽͷͨΊʹ
    %/4
   ϦόΠϯσΟϯά
   • ߈ܸͷͨΊͷ४උ
   • ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔
    )PTU"VUIPSJ[BUJPO
   ͱ͍͏
   3BDL
   ϛυϧ΢ΣΞʹ͍ͭͯ
   • %/4ϦόΠϯσΟϯάͷݟഁΓํ
   • 3BJMT
   ͷ
   )PTU"VUIPSJ[BUJPO
   ͱ͸Ͳ͏͍͏΋ͷʁ
8. 8 %/4
   ͷ͖΄Μ • %/4
   ͱ͸ͳʹ͔
   • ໰͍߹Θͤޮ཰ԽͷͨΊʹ 5PQJD
    Photo by Stephane YAICH on Unsplash
9. 9 DNS … Domain Name System %/4ͱ͸ͳʹ͔
10. 10 Πϯλʔωοτ্Ͱϗετͷಛఆ
    ʜ
    *1
    ΞυϨε %/4ͱ͸ͳʹ͔ *1W
    ΞυϨε
    *1W
    ΞυϨε
    ਺ࣈͷཏྻͳͷͰਓ͕ؒهԱɾ؅ཧ͢Δͷ͸λΠϔϯ
11. 11 ਓ͕ؒѻ͍΍͍ࣝ͢ผࢠʜ໊લ %/4ͱ͸ͳʹ͔ هԱ͠΍͍͢ɺղऍ͠΍͍͢
    ʮ෼ࢄ؅ཧʯͷߟ͑ํʹରԠͰ͖ΔʢυϝΠϯͱ%/4ͷ୉ޣຯ ͚ͩΕͲࠓ೔͸͓࿩͠·ͤΜʣ
    Πϯλʔωοτ্ʹ͓͚Δ
    lൣғz
    ʜυϝΠϯ
    υϝΠϯ͝ͱʹ෇͚ΒΕ໊ͨલ͕υϝΠϯ໊
12. 12 %/4ͷجຊతͳ໾ׂ %/4ͱ͸ͳʹ͔ υϝΠϯ໊ͱ
    *1
    ΞυϨεͱͷରԠ͚ͮΛ؅ཧ͢Δ
    ඞཁʹԠͯ͡ɺυϝΠϯ໊ʹରԠ͢Δ
    *1
    ΞυϨεΛ୳͠ग़͢
    ໊લղܾ
13. 13 υϝΠϯ໊͝ͱʹ؅ཧΛҕ೚͢Δ ໰͍߹Θͤޮ཰ԽͷͨΊʹ yucao24hours.me 99.84.130.27 ͷ
    *1
    ΞυϨε͸ TTL 60 agile.esm.co.jp 13.33.9.96 ͷ
    *1
    ΞυϨε͸ TTL 60 kaigionrails.org 185.199.109.153 ͷ
    *1
    ΞυϨε͸ TTL 3600
14. 14 υϝΠϯ໊͝ͱʹ؅ཧΛҕ೚͢Δ ໰͍߹Θͤޮ཰ԽͷͨΊʹ yucao24hours.me 99.84.130.27 ͷ
    *1
    ΞυϨε͸ TTL 60 agile.esm.co.jp 13.33.9.96 ͷ
    *1
    ΞυϨε͸ TTL 60 kaigionrails.org 185.199.109.153 ͷ
    *1
    ΞυϨε͸ TTL 3600
15. 15 υϝΠϯ໊͝ͱʹ؅ཧΛҕ೚͢Δ ໰͍߹Θͤޮ཰ԽͷͨΊʹ yucao24hours.me 99.84.130.27 ͷ
    *1
    ΞυϨε͸ TTL 60 agile.esm.co.jp 13.33.9.96 ͷ
    *1
    ΞυϨε͸ TTL 60 kaigionrails.org 185.199.109.153 ͷ
    *1
    ΞυϨε͸ TTL 3600
16. 16 υϝΠϯ໊͝ͱʹ؅ཧΛҕ೚͢Δ ໰͍߹Θͤޮ཰ԽͷͨΊʹ yucao24hours.me 99.84.130.27 ͷ
    *1
    ΞυϨε͸ TTL 60 agile.esm.co.jp 13.33.9.96 ͷ
    *1
    ΞυϨε͸ TTL 60 kaigionrails.org 185.199.109.153 ͷ
    *1
    ΞυϨε͸ TTL 3600
17. 17 ར༻ऀ yucao24hours.me ͷ
    *1
    ΞυϨεΛ
 ஌Γ͍ͨ ϑϧϦκϧό ݖҖαʔό yucao24hours.me. ໊લղܾͷ୅ߦ໾ 99.84.130.27 ໰͍߹Θͤޮ཰ԽͷͨΊʹ ໊લղܾͷ͘͠Έ
18. 18 ར༻ऀ yucao24hours.me ͷ
    *1
    ΞυϨεΛ
 ஌Γ͍ͨ ϑϧϦκϧό ݖҖαʔό yucao24hours.me. ໊લղܾͷ୅ߦ໾ 99.84.130.27 ໰͍߹Θͤޮ཰ԽͷͨΊʹ ໊લղܾͷ͘͠Έ
19. 19 ར༻ऀ yucao24hours.me ͷ
    *1
    ΞυϨεΛ
 ஌Γ͍ͨ yucao24hours.me ͷ
    *1
    ΞυϨε͸ʁ ϑϧϦκϧό 99.84.130.27 ໰͍߹Θͤޮ཰ԽͷͨΊʹ ݖҖαʔό yucao24hours.me. ໊લղܾͷ୅ߦ໾ ໊લղܾͷ͘͠Έ
20. 20 ར༻ऀ ϑϧϦκϧό yucao24hours.me 99.84.130.27 ͷ
    *1
    ΞυϨε͸ TTL 60 99.84.130.27 ໰͍߹Θͤޮ཰ԽͷͨΊʹ ݖҖαʔό yucao24hours.me. ໊લղܾͷ୅ߦ໾ ໊લղܾͷ͘͠Έ
21. 21 ར༻ऀ ϑϧϦκϧό yucao24hours.me 99.84.130.27 ͷ
    *1
    ΞυϨε͸ TTL 60 yucao24hours.me 99.84.130.27 ͷ
    *1
    ΞυϨε͸ 99.84.130.27 ໰͍߹Θͤޮ཰ԽͷͨΊʹ ݖҖαʔό yucao24hours.me. ໊લղܾͷ୅ߦ໾ ໊લղܾͷ͘͠Έ
22. 22 ར༻ऀ ϑϧϦκϧό 99.84.130.27 ໰͍߹Θͤޮ཰ԽͷͨΊʹ ݖҖαʔό yucao24hours.me. ໊લղܾͷ୅ߦ໾ ໊લղܾͷ͘͠Έ
23. 23 ϑϧϦκϧό ར༻ऀ yucao24hours.me 99.84.130.27 ͷ
    *1
    ΞυϨε͸ TTL 60 99.84.130.27 ໰͍߹Θͤޮ཰ԽͷͨΊʹ ݖҖαʔό yucao24hours.me. ໊લղܾͷ୅ߦ໾ ໊લղܾͷ͘͠Έ
24. 24 ϑϧϦκϧό ར༻ऀ yucao24hours.me 99.84.130.27 ͷ
    *1
    ΞυϨε͸ TTL 60 99.84.130.27 ໰͍߹Θͤޮ཰ԽͷͨΊʹ ݖҖαʔό yucao24hours.me. ໊લղܾͷ୅ߦ໾ ໊લղܾͷ͘͠Έ
25. 25 ར༻ऀ yucao24hours.me ͷ
    *1
    ΞυϨεΛ
 ஌Γ͍ͨ ϑϧϦκϧό ݖҖαʔό yucao24hours.me. 99.84.130.27 ໰͍߹Θͤޮ཰ԽͷͨΊʹ yucao24hours.me 99.84.130.27 ͷ
    *1
    ΞυϨε͸ TTL 60 ໊લղܾͷ୅ߦ໾ ໊લղܾͷ͘͠Έ
26. 26 ར༻ऀ ϑϧϦκϧό 99.84.130.27 yucao24hours.me 99.84.130.27 ͷ
    *1
    ΞυϨε͸ TTL 60 yucao24hours.me 99.84.130.27 ͷ
    *1
    ΞυϨε͸ ໰͍߹Θͤޮ཰ԽͷͨΊʹ ݖҖαʔό yucao24hours.me. ໊લղܾͷ୅ߦ໾ ໊લղܾͷ͘͠Έ
27. 27 %/4
    ·ͱΊ υϝΠϯ໊ͱ*1ΞυϨεͷରԠ͚ͮΛ؅ཧ͠ɺ໊લղܾΛߦ͏ͨΊͷ͘͠Έ
    ϑϧϦκϧό໊͕લղܾΛ୅ߦ͢Δ
    ϑϧϦκϧό͸ɺݖҖαʔό͔Βͷ໰͍߹Θͤ݁ՌΛҰఆ࣌ؒΩϟογϡ͠ ͯΑ͍ͱ͞ΕΔ
    ϑϧϦκϧό͸ɺҎલͷ໰͍߹Θͤ݁ՌͷΩϟογϡ͕͋Ε͹ͦΕΛ࢖ͬͯ Ϣʔβ΁Ԡ౴͠ɺݖҖαʔό΁͸৽ͨʹ໰͍߹ΘͤΛൃߦ͠ͳ͍
    ϑϧϦκϧό͕Ԡ౴಺༰ΛΩϟογϡͯ͠Α͍࣌ؒ 55- ͸֤κʔϯͷ؅ཧ ऀ͕ܾΊΒΕΔ
28. 28 ΋ͬͱ%/4Λֶͼ͍ͨͳΒʜ %/4͕Α͘Θ͔ΔڭՊॻʛ4#ΫϦΤΠςΟϒ https://www.sbcr.jp/product/4797394481/
29. 29 %/4
    ϦόΠϯσΟϯά • ߈ܸͷͨΊͷ४උ
    • ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔ 5PQJD
     Photo by Jonatan Lewczuk on Unsplash
30. 30 ߈ܸͷͨΊͷ४උ Piyostagram piyostagram.com 133.127.254.9 ߈ܸऀ
31. 31 ߈ܸͷͨΊͷ४උ ߈ܸऀ kougeki.com
32. 243.102.110.103 32 ߈ܸͷͨΊͷ४උ ߈ܸऀ ᠘αΠτ kougeki.com
33. 33 ߈ܸͷͨΊͷ४උ ߈ܸऀ ᠘αΠτ ݖҖαʔό kougeki.com 243.102.110.103 ͷ
    *1
    ΞυϨε͸ TTL 3 243.102.110.103
34. 34 ߈ܸͷͨΊͷ४උ ߈ܸऀ ᠘αΠτ kougeki.com 243.102.110.103 ͷ
    *1
    ΞυϨε͸ TTL 3 243.102.110.103 ݖҖαʔό
35. 35 ߈ܸͷͨΊͷ४උ ߈ܸऀ ᠘αΠτ kougeki.com 243.102.110.103 ͷ
    *1
    ΞυϨε͸ TTL 3 243.102.110.103 ݖҖαʔό lϩʔυޙ
    O
    ඵޙʹ kougeki.com
    ʹࣗಈͰΞΫηε͠
 ͦ͜Ͱ
    YYY
    ѱ͍͜ͱ
    Λ͢Δz
    ͕ίʔσ Οϯά͞Εͨ
 ߈ܸ༻
    +BWB4DSJQU
    ίʔυ
    Λฦ͢Α͏ʹ͓ͯ͘͠
36. 36 ߈ܸ։࢝ ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔
37. 37 ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔ ߈ܸऀ ߈ܸର৅ऀ
    :͞Μ 243.102.110.103 133.127.254.9 ϑϧϦκϧό ݖҖαʔό kougeki.com. ໊લղܾͷ୅ߦ໾ kougeki.com ΁ͷϦϯΫΛ
 ΫϦοΫ ϝʔϧ಺ͷ
38. 38 ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔ ߈ܸऀ ߈ܸର৅ऀ
    :͞Μ kougeki.com ͷ
    *1
    ΞυϨεΛ
 ஌Γ͍ͨ kougeki.com ͷ
    *1
    ΞυϨε͸ʁ ϑϧϦκϧό 243.102.110.103 133.127.254.9 ݖҖαʔό kougeki.com. ໊લղܾͷ୅ߦ໾
39. 39 ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔ ߈ܸऀ ߈ܸର৅ऀ
    :͞Μ ϑϧϦκϧό kougeki.com 243.102.110.103 ͷ
    *1
    ΞυϨε͸ 243.102.110.103 133.127.254.9 kougeki.com 243.102.110.103 ͷ
    *1
    ΞυϨε͸ TTL 3 ݖҖαʔό kougeki.com. ໊લղܾͷ୅ߦ໾
40. 40 ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔ ߈ܸऀ ߈ܸର৅ऀ
    :͞Μ ϑϧϦκϧό 243.102.110.103 133.127.254.9 kougeki.com 243.102.110.103 ͷ
    *1
    ΞυϨε͸ TTL 3 ݖҖαʔό kougeki.com. ໊લղܾͷ୅ߦ໾
41. 41 ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔ ߈ܸऀ ߈ܸର৅ऀ
    :͞Μ ϑϧϦκϧό 243.102.110.103 133.127.254.9 ݖҖαʔό kougeki.com. kougeki.com 243.102.110.103 ͷ
    *1
    ΞυϨε͸ TTL 3 ໊લղܾͷ୅ߦ໾
42. 42 ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔ ߈ܸऀ ߈ܸର৅ऀ
    :͞Μ ϑϧϦκϧό 243.102.110.103 133.127.254.9 ݖҖαʔό kougeki.com. kougeki.com 243.102.110.103 ͷ
    *1
    ΞυϨε͸ TTL 3 lϩʔυޙ
    O
    ඵޙʹ kougeki.com
    ʹࣗಈͰΞΫηε͠
 ͦ͜Ͱ
    YYY
    ѱ͍͜ͱ
    Λ͢Δz
    ͕ίʔσ Οϯά͞Εͨ
 ߈ܸ༻
    +BWB4DSJQU
    ίʔυ ໊લղܾͷ୅ߦ໾
43. 43 ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔ ߈ܸऀ ߈ܸର৅ऀ
    :͞Μ ϑϧϦκϧό 243.102.110.103 133.127.254.9 kougeki.com 243.102.110.103 ͷ
    *1
    ΞυϨε͸ TTL 3 ݖҖαʔό kougeki.com. ໊લղܾͷ୅ߦ໾
44. 44 ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔ ߈ܸऀ ߈ܸର৅ऀ
    :͞Μ ϑϧϦκϧό 243.102.110.103 133.127.254.9 kougeki.com 243.102.110.103 ͷ
    *1
    ΞυϨε͸ TTL 3 ݖҖαʔό kougeki.com. ໊લղܾͷ୅ߦ໾
45. 45 ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔ ߈ܸऀ ߈ܸର৅ऀ
    :͞Μ ϑϧϦκϧό 243.102.110.103 133.127.254.9 kougeki.com 243.102.110.103 ͷ
    *1
    ΞυϨε͸ 133.127.254.9 ݖҖαʔό kougeki.com. ໊લղܾͷ୅ߦ໾
46. 46 ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔ ߈ܸऀ ߈ܸର৅ऀ
    :͞Μ ϑϧϦκϧό 243.102.110.103 133.127.254.9 kougeki.com ͷ
    *1
    ΞυϨεΛ
 ஌Γ͍ͨ ݖҖαʔό kougeki.com. ໊લղܾͷ୅ߦ໾
47. 47 ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔ ߈ܸऀ ߈ܸର৅ऀ
    :͞Μ ϑϧϦκϧό 243.102.110.103 133.127.254.9 kougeki.com ͷ
    *1
    ΞυϨεΛ
 ஌Γ͍ͨ kougeki.com ͷ
    *1
    ΞυϨε͸ʁ ݖҖαʔό kougeki.com. ໊લղܾͷ୅ߦ໾
48. 48 ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔ ߈ܸऀ ߈ܸର৅ऀ
    :͞Μ ϑϧϦκϧό 243.102.110.103 133.127.254.9 kougeki.com ͷ
    *1
    ΞυϨε͸ kougeki.com 133.127.254.9 ͷ
    *1
    ΞυϨε͸ TTL 86400 133.127.254.9 ݖҖαʔό kougeki.com. ໊લղܾͷ୅ߦ໾
49. 49 ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔ ߈ܸऀ ߈ܸର৅ऀ
    :͞Μ ϑϧϦκϧό 243.102.110.103 133.127.254.9 ݸਓ৘ใΛ
 ൈ͖औΔFUDʜ ݖҖαʔό kougeki.com. ໊લղܾͷ୅ߦ໾
50. 50 ͲͷΑ͏ʹ߈ܸ͞ΕΔͷ͔ ͋͘·Ͱ΋
    %/4
    ͷ࢓༷Ͳ͓ΓͰ͋Δ %/4
    ͷ੬ऑੑΛͭ͘Α͏ͳ߈ܸͰ͸ͳ͍
    ʜͰ͸ɺͲ͏ͨ͠Βʁ
51. 51 %/4ϦόΠϯσΟϯά
    ·ͱΊ %/4
    ͷ࢓༷Λѱ༻ͨ͠߈ܸख๏Ͱ͢
    ϗετ໊͸ม͑ͣɺ*1ΞυϨεΛ࠮শ͞ΕΔ߈ܸͰ͢
    ϦόΠϯσΟϯάޙʹϓϥΠϕʔτωοτϫʔΫͷ*1ΞυϨε౳Λࢦఆ͞ΕΔ ͜ͱͰɺϑΝΠΞ΢Υʔϧ಺ͷϓϥΠϕʔτωοτϫʔΫ΋߈ܸର৅ͱͳΓ· ͢ʢࠓճͷΑ͏ʹΠϯλʔωοτ্ͷαʔόΛ߈ܸ͞ΕΔͱ͍͏ͷ͸͋͘·Ͱ ΋Ұྫʣ
52. 52 5PQJD
     ActionDispatch:: HostAuthorization • %/4ϦόΠϯσΟϯάͷݟഁΓํ
    • 3BJMT
    ͷ
    )PTU"VUIPSJ[BUJPO
    ͱ͸Ͳ͏͍͏΋ͷʁ Photo by Wolfgang Hasselmann on Unsplash
53. 53 %/4ϦόΠϯσΟϯάͷݟഁΓํ GET /login.html HTTP/1.1 User-Agent: Mozilla/4.0 (compatible; MSIE5.01; Windows NT) Host: kougeki.com Accept-Language: ja-JP ߈ܸͷಛੑ্ɺ
54. 54 GET /login.html HTTP/1.1 User-Agent: Mozilla/4.0 (compatible; MSIE5.01; Windows NT) Host: kougeki.com Accept-Language: ja-JP ໊લղܾͷࡍʹ࢖ΘΕͨυϝΠϯ໊͕
    )PTU
    ʹهࡌ͞ΕΔ ߈ܸͷಛੑ্ɺ %/4ϦόΠϯσΟϯάͷݟഁΓํ ˞
    9.-)UUQ3FRVFTU
    Ͱ͸ɺϢʔβʹΑΔ
    )PTU
    ϔομͷมߋ͸Ͱ͖ͳ͍
55. 55 ϦΫΤετͷ
    )PTU
    ϔομͷ஋͕
    ҙਤͨ͠υϝΠϯ໊
    
    *1ΞυϨε͔Λ
    ֬ೝ͢Ε͹ྑ͍ʂ %/4ϦόΠϯσΟϯάͷݟഁΓํ
56. 56 GET /login.html HTTP/1.1 User-Agent: Mozilla/4.0 (compatible; MSIE5.01; Windows NT) Host: piyostragram.com Accept-Language: ja-JP GET /login.html HTTP/1.1 User-Agent: Mozilla/4.0 (compatible; MSIE5.01; Windows NT) Host: kougeki.com Accept-Language: ja-JP Valid Request Invalid Request %/4ϦόΠϯσΟϯάͷݟഁΓํ
57. 57 ͦͷͨΊʹ࣮૷͞Εͨͷ͕ɺ %/4ϦόΠϯσΟϯάͷݟഁΓํ
58. 58 https://github.com/rails/rails/blob/6-0-stable/actionpack/CHANGELOG.md#rails-600beta1-january-18-2019 ͜Ε͸ɺϦΫΤετ͕Ͱ͖ΔϗετΛ໌ࣔతʹڐՄ͢Δ͜ͱͰɺ%/4ϦόΠϯσΟϯά߈ܸΛ๷ޚ͢Δɺ ৽͍͠ϛυϧ΢ΣΞͰ͢ɻ
    ͦΕͧΕͷϗετ͸
    DBTF
    PQFSBUPS
    
    ͰνΣοΫ͞ΕɺϗετΛڐՄ͢ΔͨΊͷ΋ͷͱͯ͠
    3FHFYQ
    1SPD
    *1"EES
    ΧελϜΦϒδΣΫτΛαϙʔτ͍ͯ͠·͢ɻ 3BJMT
    ͷ
    )PTU"VUIPSJ[BUJPO
    ͱ͸Ͳ͏͍͏΋ͷʁ
59. 59 3BJMT
    ͷ
    )PTU"VUIPSJ[BUJPO
    ͱ͸Ͳ͏͍͏΋ͷʁ Rails.application.config.hosts = [ IPAddr.new(“0.0.0.0/0”), # All IPv4 addresses. IPAddr.new(“::/0"), # All IPv6 addresses. “localhost” # The localhost reserved domain. ] )PTU
    ͷڐՄϦετΛ࡞੒͢Δ
60. 60 3BJMT
    ͷ
    )PTU"VUIPSJ[BUJPO
    ͱ͸Ͳ͏͍͏΋ͷʁ σϑΥϧτͰ͸ɺڐՄϦετʹ஋͕͋Δͷ͸ https://github.com/rails/rails/blob/6-0-stable/railties/lib/rails/application/ configuration.rb#L34 EFWFMPQNFOU
    ؀ڥͷΈ ڐՄϦετ͕ۭ
    
    )PTU
    ϔομ͸ݕূ͠ͳ͍
61. 61 EFWFMPQNFOU
    ؀ڥҎ֎Ͱ΋ݕূΛ༗ޮʹ͍ͨ͠৔߹͸ʜ # config/environments/#{environment}.rb Rails.application.config.hosts = [ “yucao24hours.me" # Add hostname you’d like to pass ] 3BJMT
    ͷ
    )PTU"VUIPSJ[BUJPO
    ͱ͸Ͳ͏͍͏΋ͷʁ
62. 62 3BJMT
    ͷ
    )PTU"VUIPSJ[BUJPO
    ͱ͸Ͳ͏͍͏΋ͷʁ https://github.com/rails/rails/blob/6-0-stable/actionpack/lib/action_dispatch/ middleware/host_authorization.rb#L22-L30 ڐՄϦετ ϦΫΤετϔομͷ஋
 )PTU
    9'PSXBSEFE)PTU ൑ఆ෦෼ͷϝιουͷ࣮૷ΛݟͯΈΔ
63. 63 3BJMT
    ͷ
    )PTU"VUIPSJ[BUJPO
    ͱ͸Ͳ͏͍͏΋ͷʁ https://github.com/rails/rails/blob/6-0-stable/actionpack/lib/action_dispatch/ middleware/host_authorization.rb#L56-L67 
    Λฦ͢ ൑ఆ෦෼ͷϝιουͷ࣮૷ΛݟͯΈΔ
64. 64 3BJMT
    ͷ
    )PTU"VUIPSJ[BUJPO
    ͱ͸Ͳ͏͍͏΋ͷʁ Rails.application.config.hosts << IPAddr.new(“10.0.0.1/8”) IPAddr Rails.application.config.hosts << /.*\.example\.com/ RegExp Rails.application.config.hosts << "yucao24hours.me" String
65. 65 3BJMT
    ͷ
    )PTU"VUIPSJ[BUJPO
    ͱ͸Ͳ͏͍͏΋ͷʁ υοτ͔Β࢝·Δ
    4USJOH
    ͰαϒυϝΠϯΛڐՄ͢Δ Rails.application.config.hosts << “.example.com" https://github.com/rails/rails/blob/6-0-stable/actionpack/lib/action_dispatch/ middleware/host_authorization.rb#L47-L53
66. 66 3BJMT
    ͷ
    )PTU"VUIPSJ[BUJPO
    ͱ͸Ͳ͏͍͏΋ͷʁ τϥϒϧใࠂ "84
    &-#"-#
    ͔Β
    3BJMT
    ΞϓϦ΁ͷ
    IFBMUI
    DIFDL
    ϦΫΤετ࣌ɺ
    )PTU
    ϔομ͕ ڐՄϦετʹ͋Δ΋ͷͰ͸ͳ͔ͬͨͨΊɺ
    ʹͳͬͯ͠·ͬͨ
    %PDLFS
    %FTLUPQ
    GPS
    .BD
    ͷ
    IPTUEPDLFSJOUFSOBM
    Λ࢖͍͕ͬͯͨɺڐՄϦετʹೖ Ε͍ͯͳ͔ͬͨͨΊ
    
    ʹͳͬͯ͠·ͬͨ
    
    ʹ઀ଓ͢Δࡍʹ
    MWINF
    Λ࢖͍͕ͬͯͨɺڐՄϦετʹೖΕ͍ͯͳ͔ ͬͨͨΊ
    
    ʹͳͬͯ͠·ͬͨ 66
67. 67 3BJMT
    ͷ
    )PTU"VUIPSJ[BUJPO
    ͱ͸Ͳ͏͍͏΋ͷʁ طʹϦόʔεϓϩΩγ౳Ͱ
    )PTU
    ϔομͷݕূΛ͍ͯ͠ΔͳΒ
    Θ͟Θ͟ڐՄϦετΛઃఆ͢Δඞཁ͸ͳ͍ 67
68. 68 3BJMT
    ͷ
    )PTU"VUIPSJ[BUJPO
    ͱ͸Ͳ͏͍͏΋ͷʁ ҆қʹڐՄϦετΛۭʹͤͣɺ
    ࣗ͝਎ͷαʔϏεߏ੒ʹ͋Θͤͯ
    ରԠ͠·͠ΐ͏ 68
69. 69 )PTU"VUIPSJ[BUJPO
    ·ͱΊ 3BJMT
    
    ͔Βಋೖ͞Ε·ͨ͠
    ڐՄϦετʹͳ͍υϝΠϯ໊͕
    )PTU
    9'PSXBSEFE)PTU
    ϔομʹؚ·Ε ͍ͯΔϦΫΤετʹ͸ɺσϑΥϧτͰ͸
    
    Λฦ͠·͢
    ͨͩ͠ڐՄϦετ͕ۭͰ͋Ε͹ϔομͷݕূ͸͠·ͤΜʢࠓ·Ͱͱಈ࡞͸ มΘΓ·ͤΜʣ
    ࣗαʔϏεͷߏ੒ʹ͋Θͤͯઃఆ͠·͠ΐ͏
70. 75 参考文献 DNS がよくわかる教科書 (SB クリエイティブ) https://www.sbcr.jp/product/4797394481/ 【インターネットとは】 1-2. ドメイン名とIPアドレス ～ドメイン名～ (JPNIC) https://youtu.be/l2XZBjOEK2w ドメイン名のしくみ - JPNIC https://www.nic.ad.jp/ja/dom/system.html 浸透いうな! http://www.e-ontap.com/dns/propagation/ DNS浸透の都市伝説を斬る ～ランチのおともにDNS～ https://jprs.jp/tech/material/iw2011-lunch-L1-01.pdf DNS のきほん
71. 76 参考文献 DNS rebinding attack の対策と考察 https://dnsops.jp/bof/20071119/dnsrebinding-20071119.pdf Protecting Browsers from DNS Rebinding Attacks https://crypto.stanford.edu/dns/ DNS Rebinding ～今日の用語特別版～ | 徳丸浩の日記 https://blog.tokumaru.org/2007/11/dns-rebinding.html DNS リバインディング
72. 77 参考文献 Guard against DNS rebinding attacks by permitting hosts by gsamokovarov · Pull Request #33145 · rails/rails https://github.com/rails/rails/pull/33145/ #3397 ([PATCH] CgiRequest returns incorrect host name in event of multiple proxies) - Rails Trac - Trac https://web.archive.org/web/20100618053001/http://dev.rubyonrails.org/ticket/3397 X-Forwarded-Host - HTTP | MDN https://developer.mozilla.org/ja/docs/Web/HTTP/Headers/X-Forwarded-Host ターゲットグループのヘルスチェック - Elastic Load Balancing https://docs.aws.amazon.com/ja_jp/elasticloadbalancing/latest/network/target-group-health- checks.html Application Load Balancer のヘルスチェック失敗のトラブルシューティング https://aws.amazon.com/jp/premiumsupport/knowledge-center/elb-fix-failing-health-checks-alb/ ActionDispatch::HostAuthorization(1/2)
73. 78 参考文献 Practical Web Cache Poisoning | PortSwigger Research https://portswigger.net/research/practical-web-cache-poisoning How to Configure Symfony to Work behind a Load Balancer or a Reverse Proxy (Symfony Docs) https://symfony.com/doc/current/deployment/proxies.html ActionDispatch::HostAuthorization(2/2)