Volume Mount With OS Directory Write Permissions

• Query id: a62a99d1-8196-432f-8f80-3c100b05d62a
• Query name: Volume Mount With OS Directory Write Permissions
• Platform: Terraform
• Severity: Medium
• Category: Resource Management
• URL: Github

Description

Containers can mount sensitive folders from the hosts, giving them potentially dangerous access to critical host configurations and binaries.
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - tf file

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

  spec {
    container {
      volume_mount {
        name       = "config-volume"
        mount_path = "/bin"
      }

      image = "nginx:1.7.9"
      name  = "example"

      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"
  }
}

Positive test num. 2 - tf file

resource "kubernetes_pod" "test2" {
  metadata {
    name = "terraform-example"
  }

  spec {
    container {
      volume_mount {
        name       = "config-volume"
        mount_path = "/bin"
        read_only = false
      }

      image = "nginx:1.7.9"
      name  = "example"

      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"
  }
}

Positive test num. 3 - tf file

resource "kubernetes_pod" "test3" {
  metadata {
    name = "terraform-example"
  }

  spec {
    container {
      volume_mount = [
        {
          name       = "config-volume"
          mount_path = "/bin"
          read_only = false
        }

      ]

      image = "nginx:1.7.9"
      name  = "example"

      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" "testttt" {
  metadata {
    name = "terraform-example"
  }

  spec {
    container {
      volume_mount {
        name       = "config-volume"
        mount_path = "/etc/config"
        read_only  = true
      }

      image = "nginx:1.7.9"
      name  = "example"

      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"
  }
}