Root Container Not Mounted As Read-only

• Query id: d532566b-8d9d-4f3b-80bd-361fe802f9c2
• Query name: Root Container Not Mounted As Read-only
• Platform: Terraform
• Severity: Low
• Category: Build Process
• CWE: 668
• URL: Github

Description

Check if the root container filesystem is not being mounted as read-only.
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - tf file

resource "kubernetes_pod" "positive1" {
  metadata {
    name = "terraform-example"
  }

  spec {
    container = [
     {
      image = "nginx:1.7.9"
      name  = "example22"

      security_context = {
        read_only_root_filesystem = false
      }

      env = {
        name  = "environment"
        value = "test"
      }

      port = {
        container_port = 8080
      }

      liveness_probe = {
        http_get = {
          path = "/nginx_status"
          port = 80

          http_header = {
            name  = "X-Custom-Header"
            value = "Awesome"
          }
        }

        initial_delay_seconds = 3
        period_seconds        = 3
      }
     }
     ,
     {
      image = "nginx:1.7.9"
      name  = "example22222"

      env = {
        name  = "environment"
        value = "test"
      }

      port = {
        container_port = 8080
      }

      liveness_probe = {
        http_get = {
          path = "/nginx_status"
          port = 80

          http_header = {
            name  = "X-Custom-Header"
            value = "Awesome"
          }
        }

        initial_delay_seconds = 3
        period_seconds        = 3
      }
     }
   ]


    dns_config {
      nameservers = ["1.1.1.1", "8.8.8.8", "9.9.9.9"]
      searches    = ["example.com"]

      option {
        name  = "ndots"
        value = 1
      }

      option {
        name = "use-vc"
      }
    }

    dns_policy = "None"
  }
}



resource "kubernetes_pod" "positive2" {
  metadata {
    name = "terraform-example"
  }

  spec {
    container {
      image = "nginx:1.7.9"
      name  = "example"

      security_context = {
        allow_privilege_escalation = false
      }

      env {
        name  = "environment"
        value = "test"
      }

      port {
        container_port = 8080
      }

      liveness_probe {
        http_get {
          path = "/nginx_status"
          port = 80

          http_header {
            name  = "X-Custom-Header"
            value = "Awesome"
          }
        }

        initial_delay_seconds = 3
        period_seconds        = 3
      }
    }


    dns_config {
      nameservers = ["1.1.1.1", "8.8.8.8", "9.9.9.9"]
      searches    = ["example.com"]

      option {
        name  = "ndots"
        value = 1
      }

      option {
        name = "use-vc"
      }
    }

    dns_policy = "None"
  }
}

Code samples without security vulnerabilities

Negative test num. 1 - tf file

resource "kubernetes_pod" "negative3" {
  metadata {
    name = "terraform-example"
  }

  spec {
    container = [
     {
      image = "nginx:1.7.9"
      name  = "example22"

      security_context = {
        read_only_root_filesystem = true
      }

      env = {
        name  = "environment"
        value = "test"
      }

      port = {
        container_port = 8080
      }

      liveness_probe = {
        http_get = {
          path = "/nginx_status"
          port = 80

          http_header = {
            name  = "X-Custom-Header"
            value = "Awesome"
          }
        }

        initial_delay_seconds = 3
        period_seconds        = 3
      }
     }
     ,
     {
      image = "nginx:1.7.9"
      name  = "example22222"

      security_context = {
        read_only_root_filesystem = true
      }

      env = {
        name  = "environment"
        value = "test"
      }

      port = {
        container_port = 8080
      }

      liveness_probe = {
        http_get = {
          path = "/nginx_status"
          port = 80

          http_header = {
            name  = "X-Custom-Header"
            value = "Awesome"
          }
        }

        initial_delay_seconds = 3
        period_seconds        = 3
      }
     }
   ]


    dns_config {
      nameservers = ["1.1.1.1", "8.8.8.8", "9.9.9.9"]
      searches    = ["example.com"]

      option {
        name  = "ndots"
        value = 1
      }

      option {
        name = "use-vc"
      }
    }

    dns_policy = "None"
  }
}



resource "kubernetes_pod" "negative4" {
  metadata {
    name = "terraform-example"
  }

  spec {
    container {
      image = "nginx:1.7.9"
      name  = "example"

      security_context = {
        read_only_root_filesystem = true
      }

      env {
        name  = "environment"
        value = "test"
      }

      port {
        container_port = 8080
      }

      liveness_probe {
        http_get {
          path = "/nginx_status"
          port = 80

          http_header {
            name  = "X-Custom-Header"
            value = "Awesome"
          }
        }

        initial_delay_seconds = 3
        period_seconds        = 3
      }
    }


    dns_config {
      nameservers = ["1.1.1.1", "8.8.8.8", "9.9.9.9"]
      searches    = ["example.com"]

      option {
        name  = "ndots"
        value = 1
      }

      option {
        name = "use-vc"
      }
    }

    dns_policy = "None"
  }
}