cis-docker-v170-4-9

name	cis-docker-v170-4.9
description	Ensure that COPY is used instead of ADD in Dockerfiles
category	cis-docker
version	1.7.0
author	cyberstrike-official
tags	["cis","docker","images","configuration","dockerfile"]
cis_id	4.9
cis_benchmark	CIS Docker Benchmark v1.7.0
tech_stack	["docker"]
cwe_ids	["CWE-494"]
chains_with	[]
prerequisites	[]
severity_boost	{}

CIS Docker Benchmark v1.7.0 - Control 4.9

Profile Applicability

• Level 1 - Docker - Linux

Description

You should use the COPY instruction instead of the ADD instruction in the Dockerfile.

Rationale

The COPY instruction simply copies files from the local host machine to the container file system. The ADD instruction could potentially retrieve files from remote URLs and perform operations such as unpacking them. The ADD instruction therefore introduces security risks. For example, malicious files may be directly accessed from URLs without scanning, or there may be vulnerabilities associated with decompressing them.

Impact

Care needs to be taken in implementing this control if the application requires functionality that is part of the ADD instruction, for example, if you need to retrieve files from remote URLs.

Audit Procedure

Run the command below to get the list of images:

docker images

Run the command below against each image in the list above and look for any ADD instructions:

docker history <IMAGE_ID>

Alternatively, if you have access to the Dockerfile for the image, you should verify that there are no ADD instructions.

Remediation

You should use COPY rather than ADD instructions in Dockerfiles.

Default Value

Not Applicable

References

1. https://docs.docker.com/develop/develop-images/dockerfile_best-practices/#add-or-copy

CIS Controls

v8:

• 16.7 Use Standard Hardening Configuration Templates for Application Infrastructure - Use standard, industry-recommended hardening configuration templates for application infrastructure components. This includes underlying servers, databases, and web servers, and applies to cloud containers, Platform as a Service (PaaS) components, and SaaS components. Do not allow in-house developed software to weaken configuration hardening.

v7:

• 5.2 Maintain Secure Images - Maintain secure images or templates for all systems in the enterprise based on the organization's approved configuration standards. Any new system deployment or existing system that becomes compromised should be imaged using one of those images or templates.