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unfunco / terraform-aws-oidc-github

Terraform module to configure GitHub Actions as an IAM OIDC identity provider in AWS.
https://registry.terraform.io/modules/unfunco/oidc-github/aws/latest
Apache License 2.0
97 stars 53 forks source link

thumbprint for (what i believe is) the github key, and not CA key. #7

Closed kevcube closed 2 years ago

kevcube commented 2 years ago

Based on the output of openssl s_client -servername token.actions.githubusercontent.com -showcerts -connect token.actions.githubusercontent.com:443 (below) I believe module uses the thumbprint of the CA Authority's signing cert,

1 s:/C=US/O=DigiCert Inc/CN=DigiCert TLS RSA SHA256 2020 CA1
   i:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert Global Root CA
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

fingerprint:

``` openssl x509 -fingerprint -noout <<< '-----BEGIN CERTIFICATE----- MIIE6jCCA9KgAwIBAgIQCjUI1VwpKwF9+K1lwA/35DANBgkqhkiG9w0BAQsFADBh MQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMRkwFwYDVQQLExB3 d3cuZGlnaWNlcnQuY29tMSAwHgYDVQQDExdEaWdpQ2VydCBHbG9iYWwgUm9vdCBD QTAeFw0yMDA5MjQwMDAwMDBaFw0zMDA5MjMyMzU5NTlaME8xCzAJBgNVBAYTAlVT MRUwEwYDVQQKEwxEaWdpQ2VydCBJbmMxKTAnBgNVBAMTIERpZ2lDZXJ0IFRMUyBS U0EgU0hBMjU2IDIwMjAgQ0ExMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKC AQEAwUuzZUdwvN1PWNvsnO3DZuUfMRNUrUpmRh8sCuxkB+Uu3Ny5CiDt3+PE0J6a qXodgojlEVbbHp9YwlHnLDQNLtKS4VbL8Xlfs7uHyiUDe5pSQWYQYE9XE0nw6Ddn g9/n00tnTCJRpt8OmRDtV1F0JuJ9x8piLhMbfyOIJVNvwTRYAIuE//i+p1hJInuW raKImxW8oHzf6VGo1bDtN+I2tIJLYrVJmuzHZ9bjPvXj1hJeRPG/cUJ9WIQDgLGB Afr5yjK7tI4nhyfFK3TUqNaX3sNk+crOU6JWvHgXjkkDKa77SU+kFbnO8lwZV21r eacroicgE7XQPUDTITAHk+qZ9QIDAQABo4IBrjCCAaowHQYDVR0OBBYEFLdrouqo qoSMeeq02g+YssWVdrn0MB8GA1UdIwQYMBaAFAPeUDVW0Uy7ZvCj4hsbw5eyPdFV MA4GA1UdDwEB/wQEAwIBhjAdBgNVHSUEFjAUBggrBgEFBQcDAQYIKwYBBQUHAwIw EgYDVR0TAQH/BAgwBgEB/wIBADB2BggrBgEFBQcBAQRqMGgwJAYIKwYBBQUHMAGG GGh0dHA6Ly9vY3NwLmRpZ2ljZXJ0LmNvbTBABggrBgEFBQcwAoY0aHR0cDovL2Nh Y2VydHMuZGlnaWNlcnQuY29tL0RpZ2lDZXJ0R2xvYmFsUm9vdENBLmNydDB7BgNV HR8EdDByMDegNaAzhjFodHRwOi8vY3JsMy5kaWdpY2VydC5jb20vRGlnaUNlcnRH bG9iYWxSb290Q0EuY3JsMDegNaAzhjFodHRwOi8vY3JsNC5kaWdpY2VydC5jb20v RGlnaUNlcnRHbG9iYWxSb290Q0EuY3JsMDAGA1UdIAQpMCcwBwYFZ4EMAQEwCAYG Z4EMAQIBMAgGBmeBDAECAjAIBgZngQwBAgMwDQYJKoZIhvcNAQELBQADggEBAHer t3onPa679n/gWlbJhKrKW3EX3SJH/E6f7tDBpATho+vFScH90cnfjK+URSxGKqNj OSD5nkoklEHIqdninFQFBstcHL4AGw+oWv8Zu2XHFq8hVt1hBcnpj5h232sb0HIM ULkwKXq/YFkQZhM6LawVEWwtIwwCPgU7/uWhnOKK24fXSuhe50gG66sSmvKvhMNb g0qZgYOrAKHKCjxMoiWJKiKnpPMzTFuMLhoClw+dj20tlQj7T9rxkTgl4ZxuYRiH as6xuwAwapu3r9rxxZf+ingkquqTgLozZXq8oXfpf2kUCwA/d5KxTVtzhwoT0JzI 8ks5T1KESaZMkE4f97Q= -----END CERTIFICATE-----' # SHA1 Fingerprint=69:38:FD:4D:98:BA:B0:3F:AA:DB:97:B3:43:96:83:1E:37:80:AE:A1 ```

instead of using the cert issued by this CA to GitHub,

0 s:/C=US/ST=California/L=San Francisco/O=GitHub, Inc./CN=*.actions.githubusercontent.com
   i:/C=US/O=DigiCert Inc/CN=DigiCert TLS RSA SHA256 2020 CA1
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

fingerprint:

``` openssl x509 -fingerprint -noout <<< '-----BEGIN CERTIFICATE----- MIIG9jCCBd6gAwIBAgIQCFCR4fqbkQJJbzQZsc87qzANBgkqhkiG9w0BAQsFADBP MQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMSkwJwYDVQQDEyBE aWdpQ2VydCBUTFMgUlNBIFNIQTI1NiAyMDIwIENBMTAeFw0yMjAxMTEwMDAwMDBa Fw0yMzAxMTEyMzU5NTlaMHsxCzAJBgNVBAYTAlVTMRMwEQYDVQQIEwpDYWxpZm9y bmlhMRYwFAYDVQQHEw1TYW4gRnJhbmNpc2NvMRUwEwYDVQQKEwxHaXRIdWIsIElu Yy4xKDAmBgNVBAMMHyouYWN0aW9ucy5naXRodWJ1c2VyY29udGVudC5jb20wggEi MA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQCcHl5GgNgXYUI5Zz085Ar9wSiI gdDnOkaXof2u3pcJ1138Tlz6aheVqXfJ8MOAups0LTr9j/dTHAGWKQz0qdyUdYIJ FwiOlkmphoP+a4xVJXbdVVN7qvmfV8f0YnG5oGVyx9hDl/30JReVIYPbC8JNSiIW 2jMYnjqPu41tPclNNroW9K8gJUzT/WE4LRHohOmR1GbC1xQ8YlFS6pFs+Xuznou8 TzO8PsXRdaDe/7pYZgR/Otv5XLY5siCBraMuxtj1g4Z/Tz8d2Z+sMPIxtHZjxmcu LPfIix6cARSpJFgGF7Yh9vgLK9jEkgfuU1Nnshv7S6ylIn5SfHNToQjCRSPJAgMB AAGjggOgMIIDnDAfBgNVHSMEGDAWgBS3a6LqqKqEjHnqtNoPmLLFlXa59DAdBgNV HQ4EFgQUibMM9Yecb/WbuZDkxiGVR39k0QMwSQYDVR0RBEIwQIIfKi5hY3Rpb25z LmdpdGh1YnVzZXJjb250ZW50LmNvbYIdYWN0aW9ucy5naXRodWJ1c2VyY29udGVu dC5jb20wDgYDVR0PAQH/BAQDAgWgMB0GA1UdJQQWMBQGCCsGAQUFBwMBBggrBgEF BQcDAjCBjwYDVR0fBIGHMIGEMECgPqA8hjpodHRwOi8vY3JsMy5kaWdpY2VydC5j b20vRGlnaUNlcnRUTFNSU0FTSEEyNTYyMDIwQ0ExLTQuY3JsMECgPqA8hjpodHRw Oi8vY3JsNC5kaWdpY2VydC5jb20vRGlnaUNlcnRUTFNSU0FTSEEyNTYyMDIwQ0Ex LTQuY3JsMD4GA1UdIAQ3MDUwMwYGZ4EMAQICMCkwJwYIKwYBBQUHAgEWG2h0dHA6 Ly93d3cuZGlnaWNlcnQuY29tL0NQUzB/BggrBgEFBQcBAQRzMHEwJAYIKwYBBQUH MAGGGGh0dHA6Ly9vY3NwLmRpZ2ljZXJ0LmNvbTBJBggrBgEFBQcwAoY9aHR0cDov L2NhY2VydHMuZGlnaWNlcnQuY29tL0RpZ2lDZXJ0VExTUlNBU0hBMjU2MjAyMENB MS0xLmNydDAMBgNVHRMBAf8EAjAAMIIBfQYKKwYBBAHWeQIEAgSCAW0EggFpAWcA dQCt9776fP8QyIudPZwePhhqtGcpXc+xDCTKhYY069yCigAAAX5IjyPvAAAEAwBG MEQCIDxMGruNl33xLmOdh2UdMxA3aiuIX3vgeXSuXRce6sqBAiApoOxk2sfxfZdw cMxXuM0B8bfgGiQ7IlG14wRa7KQioAB3ADXPGRu/sWxXvw+tTG1Cy7u2JyAmUeo/ 4SrvqAPDO9ZMAAABfkiPI8kAAAQDAEgwRgIhAJJmNVWqVfFlQLdX8sbbQ9VmJA5K 28ldvwLQpnJopgFzAiEAsGYoIzVOBazT96kGYIuJ3k+Zya7PsFtPVyUbOom55PcA dQCzc3cH4YRQ+GOG1gWp3BEJSnktsWcMC4fc8AMOeTalmgAAAX5IjyPnAAAEAwBG MEQCIE0NMqwPjqYJwxYqrh7CVueH1rWvKYvRj8cvv3fr7Ku5AiBGFfeJ+Nsy3VCW TAih+ito29SvJ0TJrDsyHy3PhkmZ6jANBgkqhkiG9w0BAQsFAAOCAQEAih09kwU8 8j/R3/xDkV/2Td/ZbgzUPrrjnMqL32Kv8zqPb0AnaOZbA9XqMuQimLDPqr7fTtKR BRhXStaNT5s7zZm3g9P+Xsxl2XSiuTbR0Y9MOmfgWA0Jv3vw8zq/etdGBrV0stQ/ JB2GKteYl9hP7eOj0xaNg/ylaCDONG084lqVlugggmsW9RgN3zAESmALahezuzlN G5asPhNDCIRyo3mm0hHCV4/Kvoura/bGVkc7Wkk6q/cplN5VCSq9wYk2ugEaxsc1 YeqXpxQtRVJTF/UtuNpWS+Tp1COx3DiaoTjCmEImSzYarfZ7QIMR9opxJEPAB52h s/oLX5ruUXwvIw== -----END CERTIFICATE-----' # SHA1 Fingerprint=15:E2:91:08:71:81:11:E5:9B:3D:AD:31:95:46:47:E3:C3:44:A2:31 ```
kevcube commented 2 years ago

@unfunco I've validated that role assumption still functions, please double check my assumptions about the cert chain!! If they're correct then this is a critical bug.

unfunco commented 2 years ago

Investigating further, I think it's okay. The thumbprint that was being used is the one documented by GitHub in this post: https://github.blog/changelog/2022-01-13-github-actions-update-on-oidc-based-deployments-to-aws/

kevcube commented 2 years ago

Ok - yeah looks like it's secure enough to be validating the intermediate CA and also the GitHub domain.