Docker From alias is not unique for multistage builds misconfiguration detected in code

Rule Details

Cortex AppSec Rule ID	APPSEC_DOCKER_11
Category - Subcategory	Compute - Startup Script Leaks
Provider	OTHER
Severity	LOW
Framework	DOCKER

Impact

This rule detects whether each FROM instruction in a Dockerfile uses a unique alias when building multistage images. Aliases help to identify stages, making Dockerfiles more readable and maintainable. Enforcing unique aliases ensures clarity, prevents conflicts and avoids any unintentional overwriting of stages.

How to Fix

To mitigate this issue, ensure that each FROM instruction in your multistage Dockerfile uses a unique alias.

Example: [source,go]

FROM node:14 as builder ...

• FROM node:14 as builder # Duplicate alias
• FROM node:14 as builder_2 # Unique alias ...

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