# Ensure that TLS CA certificate file ownership is set to root:root to root.

- Source: https://support.icompaas.com/support/solutions/articles/62000234338-ensure-that-tls-ca-certificate-file-ownership-is-set-to-root-root-to-root-
- Section: [Solutions](https://support.icompaas.com/support/solutions) › [CIS Docker Benchmark v1.7.0](https://support.icompaas.com/support/solutions/62000112687) › [CIS Docker Benchmark](https://support.icompaas.com/support/solutions/folders/62000169241)
- Last updated: 2026-05-29
- Publisher: iCompaas, Inc. (https://www.icompaas.com)

**Profile Applicability:**

-   **Level 1**
    

**Description:**

The TLS CA certificate file, used to authenticate Docker registry communication, should have its ownership set to root:root to ensure that unauthorized users cannot modify the certificate, which could undermine secure communication.

**Rationale:**

The ownership of the TLS CA certificate file must be restricted to root:root to prevent unauthorized modification by non-administrative users. Modifying the certificate could allow an attacker to intercept or manipulate Docker's secure communication, leading to a security compromise.

**Impact:**

**Pros:**

-   Ensures the integrity of the TLS certificate by restricting modification to root users only.
    
-   Enhances Docker's security by preventing unauthorized access to the certificate file.
    

**Cons:**

-   Requires periodic checks to ensure the certificate file ownership remains correct, especially after system changes or updates.
    

**Default Value:**

By default, the TLS CA certificate file is owned by root:root, unless modified by administrative error or unauthorized access.

**Pre-requisites:**

-   Administrative privileges on the Docker host system.
    
-   Access to the file system to inspect and modify file ownership.
    

**Remediation:**

**Test Plan:**

**Using AWS Console:**

1.  Log in to the EC2 instance running Docker.
    
2.  Verify the ownership of the TLS CA certificate file:  
    
    ls -l /etc/docker/certs.d/<registry>/ca.crt
    

**Using AWS CLI:**

1.  Connect to the EC2 instance where Docker is running.
    
2.  Run the following command to check the ownership of the TLS CA certificate file:  
    
    ls -l /etc/docker/certs.d/<registry>/ca.crt
    

**Implementation Plan:**

**Using AWS Console:**

1.  Log in to the EC2 instance.
    
2.  Set the ownership of the TLS CA certificate file to root:root:  
    
    sudo chown root:root /etc/docker/certs.d/<registry>/ca.crt
    
3.  Restart Docker to ensure the changes take effect:  
    
    sudo systemctl restart docker
    

**Using AWS CLI:**

1.  Use SSM to modify the ownership of the TLS CA certificate file and restart Docker:  
    
    aws ssm send-command --document-name "AWS-RunShellScript" --targets "Key=instanceIds,Values=instance\_id" --parameters 'commands=\["sudo chown root:root /etc/docker/certs.d/<registry>/ca.crt && sudo systemctl restart docker"\]'
    

**Backout Plan:**

**Using AWS Console:**

1.  Log in to the EC2 instance.
    
2.  Revert the ownership of the TLS CA certificate file if necessary:  
    
    sudo chown <previous-owner>:<previous-group> /etc/docker/certs.d/<registry>/ca.crt
    
3.  Restart Docker:  
    
    sudo systemctl restart docker
    

**Using AWS CLI:**

1.  Use SSM to revert the ownership and restart Docker:  
    
    aws ssm send-command --document-name "AWS-RunShellScript" --targets "Key=instanceIds,Values=instance\_id" --parameters 'commands=\["sudo chown <previous-owner>:<previous-group> /etc/docker/certs.d/<registry>/ca.crt && sudo systemctl restart docker"\]'
    

**References:**

-   [Docker TLS Security Documentation](https://docs.docker.com/engine/security/https/)
    
-   [Docker Insecure Registry Reference  
      
      
    ](https://docs.docker.com/registry/insecure/)

## Related compliance guidance

- [SOC 2 compliance: a practical implementation guide for cloud-native SaaS teams](https://support.icompaas.com/compliance/soc-2-trust-services-criteria): Configuration checks like this one are the technical half of a SOC 2 / ISO 27001 programme — the guide shows where they fit, what else an auditor expects, and how to evidence them.
- [ISO/IEC 27001:2022 compliance: a practical implementation guide](https://support.icompaas.com/compliance/iso-27001-2022): ISO 27001 Annex A.8 (technological controls) is where cloud hardening evidence lands; the guide shows how to run the ISMS around it.