Disallow Specific Users in SBOM

Type: Rule
ID: sbom-disallowed-users
Source: v2/rules/images/banned-users.yaml
Rego Source: banned-users.rego
Labels: SBOM, Image

Verify specific users are not allowed in an SBOM.

note

This rule requires Image SBOM. See here for more details.

tip

Signed Evidence for this rule IS NOT required by default but is recommended.

warning

Rule requires evaluation with a target or an asset input. Without one, it will be disabled unless the --all-evidence flag is provided.

info

Rule is scoped by target and product.

Usage example

uses: images/banned-users@v2
with:
  users:
    - root

Mitigation

Prevents the execution of container images with default or disallowed user accounts reducing the risk of privilege escalation and ensuring that only secure, non-privileged user configurations are used.

Description

This rule inspects the CycloneDX SBOM evidence for a container image to ensure that the image is not configured to run with a banned default user. It does so by examining the metadata.component.properties array for a property with the name "user". The value of this property is then compared against a list of disallowed users specified in the configuration (via with.users). If the image is found to be running as a banned user (for example, "root"), a violation is recorded.

Evidence Requirements:

• Evidence must be provided in the CycloneDX JSON format.
• The SBOM must include a metadata.component.properties array with an entry where the property name is "user".
• The disallowed user list (e.g., ["root"]) must be provided in the with.users parameter.

Evidence Requirements

Field	Value
signed	False
content_body_type	cyclonedx-json
target_type	container
filter-by	['target', 'product']

Input Definitions

Parameter	Type	Required	Description	Default
users	array	False	A list of disallowed users. Each entry should be a string representing a username.	['root']