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aws

EFS file system has no access points allowing access to the root directory

efs_access_point_enforce_root_directory
Service: efsSeverity: medium
OfficialBuilt-inVerified
Categories:vulnerabilities
Resource Type:AwsEfsAccessPoint

Amazon EFS access points are evaluated to ensure they enforce a non-root directory. The check identifies access points whose configured root directory Path is /, meaning clients would mount the file system's root instead of a scoped subdirectory.

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Risk

Exposing the file system root via an access point undermines confidentiality and integrity by allowing traversal beyond intended datasets. Attackers or misconfigured apps could:

  • Read sensitive directories
  • Modify or delete shared data
  • Pivot across tenants, impacting availability

Run this check with Prowler

Run in Prowler Cloud
Run
prowler aws --checks efs_access_point_enforce_root_directory

Recommendation

Apply least privilege: set each access point Path to a dedicated subdirectory and avoid /.

  • Use per-application access points
  • Enforce POSIX identity and directory permissions
  • Layer controls (network segmentation, monitoring) for defense in depth

Remediation

CLI

aws efs delete-access-point --access-point-id <access-point-id>

Terraform

# Terraform: EFS access point enforcing a non-root directory
resource "aws_efs_access_point" "<example_resource_name>" {
  file_system_id = "<example_resource_id>"

  root_directory {
    path = "/data"  # Critical: not "/"; enforces a subdirectory as root to pass the check
  }
}

NativeIaC

# CloudFormation: EFS access point enforcing a non-root directory
Resources:
  <example_resource_name>:
    Type: AWS::EFS::AccessPoint
    Properties:
      FileSystemId: <example_resource_id>
      RootDirectory:
        Path: /data  # Critical: set to a non-root path to avoid "/" and pass the check
        # This enforces the access point root to /data instead of the file system root

Other

1In the AWS Console, go to EFS > Access points
2Select the access point showing Root directory as /
3Click Delete and confirm
4Click Create access point
5Select the file system and set Root directory Path to a non-root path (for example, /data)
6Click Create access point

Check Code

from prowler.lib.check.models import Check, Check_Report_AWS
from prowler.providers.aws.services.efs.efs_client import efs_client


class efs_access_point_enforce_root_directory(Check):
    def execute(self):
        findings = []
        for fs in efs_client.filesystems.values():
            if fs.access_points:
                report = Check_Report_AWS(metadata=self.metadata(), resource=fs)
                report.status = "PASS"
                report.status_extended = f"EFS {fs.id} does not have any access point allowing access to the root directory."
                access_points = []
                for access_point in fs.access_points:
                    if access_point.root_directory_path == "/":
                        access_points.append(access_point)
                if access_points:
                    report.status = "FAIL"
                    report.status_extended = f"EFS {fs.id} has access points which allow access to the root directory: {', '.join([ap.id for ap in access_points])}."
                findings.append(report)
        return findings

References