Container Runs Unmasked

• Query id: 0ad60203-c050-4115-83b6-b94bde92541d
• Query name: Container Runs Unmasked
• Platform: Terraform
• Severity: Medium
• Category: Insecure Configurations
• URL: Github

Description

Check if a container has full access (unmasked) to the host’s /proc command, which would allow to retrieve sensitive information and possibly change the kernel parameters in runtime.
Documentation

Code samples

Code samples with security vulnerabilities

Postitive test num. 1 - tf file

resource "kubernetes_pod_security_policy" "example" {
  metadata {
    name = "terraform-example"
  }
  spec {
    privileged                 = false
    allow_privilege_escalation = false
    allowed_proc_mount_types   = ["Unmasked"]

    volumes = [
      "configMap",
      "emptyDir",
      "projected",
      "secret",
      "downwardAPI",
      "persistentVolumeClaim",
    ]

    run_as_user {
      rule = "MustRunAsNonRoot"
    }

    se_linux {
      rule = "RunAsAny"
    }

    supplemental_groups {
      rule = "MustRunAs"
      range {
        min = 1
        max = 65535
      }
    }

    fs_group {
      rule = "MustRunAs"
      range {
        min = 1
        max = 65535
      }
    }

    read_only_root_filesystem = true
  }
}

Code samples without security vulnerabilities

Negative test num. 1 - tf file

resource "kubernetes_pod_security_policy" "example" {
  metadata {
    name = "terraform-example"
  }
  spec {
    privileged                 = false
    allow_privilege_escalation = false
    allowed_proc_mount_types   = ["Default"]

    volumes = [
      "configMap",
      "emptyDir",
      "projected",
      "secret",
      "downwardAPI",
      "persistentVolumeClaim",
    ]

    run_as_user {
      rule = "MustRunAsNonRoot"
    }

    se_linux {
      rule = "RunAsAny"
    }

    supplemental_groups {
      rule = "MustRunAs"
      range {
        min = 1
        max = 65535
      }
    }

    fs_group {
      rule = "MustRunAs"
      range {
        min = 1
        max = 65535
      }
    }

    read_only_root_filesystem = true
  }
}