sbomaudit 0.4.1

Audit SBOM contents

SBOMAUDIT

SBOMAUDIT reports on the quality of the contents of an SBOM (Software Bill of Materials) by performing a number of checks. SBOMs are supported in a number of formats including SPDX and CycloneDX.

Installation

To install use the following command:

pip install sbomaudit

Alternatively, just clone the repo and install dependencies using the following command:

pip install -U -r requirements.txt

The tool requires Python 3 (3.7+). It is recommended to use a virtual python environment especially if you are using different versions of python. virtualenv is a tool for setting up virtual python environments which allows you to have all the dependencies for the tool set up in a single environment, or have different environments set up for testing using different versions of Python.

Usage

usage: sbomaudit [-h] [-i INPUT_FILE] [--offline] [--cpecheck] [--purlcheck] [--disable-license-check] [--age AGE] [--maxage MAXAGE] [--allow ALLOW] [--deny DENY] [--verbose] [--debug] [-o OUTPUT_FILE] [-V]

SBOMAudit reports on the quality of the contents of a SBOM.

options:
  -h, --help            show this help message and exit
  -V, --version         show program's version number and exit

Input:
  -i INPUT_FILE, --input-file INPUT_FILE
                        Name of SBOM file
  --offline             operate in offline mode
  --cpecheck            check for CPE specification
  --purlcheck           check for PURL specification
  --disable-license-check
                        disable check for SPDX License identifier
  --age AGE             minimum age of package (as integer representing days) to report (default: 0)
  --maxage MAXAGE       maximum age of package (as integer representing years) to report (default: 2)
  --allow ALLOW         Name of allow list file
  --deny DENY           Name of deny list file
  --verbose             verbose reporting

Output:
  --debug               add debug information
  -o OUTPUT_FILE, --output-file OUTPUT_FILE
                        output filename (default: output to stdout)

Operation

The --input-file option is used to specify the SBOM to be processed. The format of the SBOM is determined according to the following filename conventions.

SBOM	Format	Filename extension
SPDX	TagValue	.spdx
SPDX	JSON	.spdx.json
SPDX	YAML	.spdx.yaml
SPDX	YAML	.spdx.yml
CycloneDX	JSON	.json
CycloneDX	XML	.xml

The --offline option is used when the tool is used in an environment where access to external systems is not available. This means that some audit checks are not performed.

The --cpecheck and --purlcheck options are used to enable additional checks related to a SBOM component.

The --disable-license-check option is used to disable the check that the licenses have valid SPDX License identifiers.

The --age option can be used to report if a recent release of a package is being used.

The --maxage option can be used to report if the release date of a package, which is not the latest version, is greater than the value specified. The default value is 2 years.

The --allow and --deny options are used to specify additional checks related to licenses and packages which are to be allowed or denied within a SBOM component. An allow file contains the set of licenses and packages which to be contained within the SBOM; this may be useful to ensure that the SBOM does not contain any unapproved licenses or packages not identified in a software design. A deny file is used to specify the licenses and packages which must not be contained within the SBOM.

The --verbose option can be used to report the results of all the checks performed; the default is just report failed checks and summaries.

The --output-file option is used to control the destination of the output generated by the tool. The default is to report to the console but can be stored in a file (specified using --output-file option).

Allow and Deny list file formats

The files are text files consisting of two sections

• List of SPDX license identifiers
• Lst of Package names

Each section is optional.

These files can be used to enforce a development policy e.g. use the deny list to report on licences which are not approved.

In this sample allow file, this would only allow cemponents with the MIT, Apache-2.0 or BSD-3-Clause licenses. It is also only expecting a single package 'click'.

# This is an example ALLOW list file for SBOMAUDIT
# Allowed licenses
[license]
MIT
Apache-2.0
BSD-3-Clause
# Allowed packages 
[package] 
click                                                           

Checks Performed

The following section identifies the checks which are performed.

SBOM Format

The following checks are performed:

• Check that the version of the SBOM is either version 2.2 or 2.3 (SPDX) or version 1.3, 1.4 or 1.5 (CycloneDX).

• Check that a creator is defined.

• Check that the time that the SBOM is created is defined.

Files

The following checks are performed for each file item:

• Check that a file name is specified.

• Check that the file type is specified.

• Check that a license is specified and that the license identified is a valid SPDX License identifier. Note that NOASSERTION is not considered a valid license.

• Check that the license is an OSI Approved license.

• Optionally check that the license is allowed as specified in the ALLOW list

• Optionally check that the license is not included in the licenses specified in the DENY list

• Check that a copyright statement is specified. Note that NOASSERTION is not considered a valid copyright statement.

Packages

The following checks are performed on each package item:

• Check that a package name is specified.

• Optionally check that the package name is allowed as specified in the ALLOW list

• Optionally check that the package name is not included in the packages specified in the DENY list

• Check that a supplier is specified.

• Check that a version is specified.

• Check that the package version is the latest released version of the package. The latest version checks are only performed if the --offline option is not specified.

• Check that a mature version of the package is being used as determined by the value specified in the --age option. The release date checks are only performed if the --offline option is not specified.

• Check the age of a package being used, which is not the latest released version, is greater than the value specified in the --maxage option. The check is only performed if the --offline option is not specified.

• Check that a license is specified and that the license identified is a valid SPDX License identifier. Note that NOASSERTION is not considered a valid license.

• Check that the license is an OSI Approved license.

• Optionally check that the license is allowed as specified in the ALLOW list

• Optionally check that the license is not included in the licenses specified in the DENY list

• Check that a PURL specification is provided for the package.

• Check that a CPE specification is provided for the package.

Latest package version checks

The checks for the latest package version are performed for packages within the following language ecosystems:

• dart
• go
• java
• javascript
• .net
• perl
• python
• r
• ruby
• rust
• swift

Relationships

The following checks are performed:

• Check that relationships are defined.

• Check that every file is included in at least one relationship.

• Check that every package is included in at least one relationship.

NTIA Conformance

The following checks are performed:

• Check that the contents of the SBOM meet the minimum requirements for an SBOM as defined by the NTIA.

Implementing a Development Policy

The use of the --age, --maxage, --allow and --deny options can be used to enforce a development policy.

A report of the checks which violate against the development policy is contained in a section within the output file.

Example

Given the following SBOM (click.json)

{
  "$schema": "http://cyclonedx.org/schema/bom-1.4.schema.json",
  "bomFormat": "CycloneDX",
  "specVersion": "1.4",
  "serialNumber": "urn:uuided03b5fe-42a8-41ee-b68f-114aa6fcead9",
  "version": 1,
  "metadata": {
    "timestamp": "2023-02-21T16:09:46Z",
    "tools": [
      {
        "name": "sbom4python",
        "version": "0.8.0"
      }
    ],
    "component": {
      "type": "application",
      "bom-ref": "CDXRef-DOCUMENT",
      "name": "Python-click"
    }
  },
  "components": [
    {
      "type": "library",
      "bom-ref": "1-click",
      "name": "click",
      "version": "8.1.3",
      "supplier": {
        "name": "Armin Ronacher",
        "contact": [
          {
            "email": "[e-mail]"
          }
        ]
      },
      "cpe": "cpe:2.3:a:armin_ronacher:click:8.1.3:*:*:*:*:*:*:*",
      "description": "Composable command line interface toolkit",
      "licenses": [
        {
          "license": {
            "id": "BSD-3-Clause",
            "url": "https://opensource.org/licenses/BSD-3-Clause"
          }
        }
      ],
      "externalReferences": [
        {
          "url": "https://palletsprojects.com/p/click/",
          "type": "other",
          "comment": "Home page for project"
        }
      ],
      "purl": "pkg:pypi/click@8.1.3"
    }
  ],
  "dependencies": [
    {
      "ref": "CDXRef-DOCUMENT",
      "dependsOn": [
        "1-click"
      ]
    }
  ]
}

The following command will audit the contents of the SBOM.

sbomaudit --input-file click.json
╭─────────────────────╮
│ SBOM Format Summary │
╰─────────────────────╯
[x] SBOM Format
╭─────────────────╮
│ Package Summary │
╰─────────────────╯
[x] Package Summary
╭───────────────────────╮
│ Relationships Summary │
╰───────────────────────╯
[x] Relationship Summary
╭──────────────╮
│ NTIA Summary │
╰──────────────╯
[x] NTIA Summary
╭────────────────────╮
│ SBOM Audit Summary │
╰────────────────────╯
[x] Checks passed 11
[x] Checks failed 0                                                              

A verbose report and summary of the contents of the SBOM to the console.

sbomaudit --input-file click.json --verbose --cpecheck --purlcheck
╭─────────────────────╮
│ SBOM Format Summary │
╰─────────────────────╯
[x] Up to date CycloneDX Version
[x] SBOM Creator identified
[x] SBOM Creation time defined
╭─────────────────╮
│ Package Summary │
╰─────────────────╯
[x] Supplier included for package click
[x] Version included for package click
[x] License included for package click
[x] SPDX Compatible License id included for package click
[x] OSI Approved license for click
[x] Non-deprecated license for click
[x] Using latest version of package click
[x] Using mature version of package click
[x] Using old version of package click
[x] CPE name included for package click
[x] PURL included for package click
[x] PURL name compatible with package click
[x] NTIA compliant
╭───────────────────────╮
│ Relationships Summary │
╰───────────────────────╯
[x] Dependency relationships provided for NTIA compliance
[x] Dependency relationship found for click
╭──────────────╮
│ NTIA Summary │
╰──────────────╯
[x] NTIA conformant
╭────────────────────╮
│ SBOM Audit Summary │
╰────────────────────╯
[x] Checks passed 19
[x] Checks failed 0

The following is an example of the output which is generated when some checks on the contents of the SBOM fail.

╭─────────────────────╮
│ SBOM Format Summary │
╰─────────────────────╯
[x] SBOM Format
╭─────────────────╮
│ Package Summary │
╰─────────────────╯
[ ] Using latest version of package black: Version is 22.12.0; latest is 23.1.0
[ ] Using latest version of package mypy-extensions: Version is 0.4.3; latest is 1.0.0
[ ] SPDX Compatible License id included for package pathspec: MPL 2.0
[ ] Using latest version of package pathspec: Version is 0.10.3; latest is 0.11.0
[ ] License included for package platformdirs: MISSING
[ ] SPDX Compatible License id included for package platformdirs: NOASSERTION
[ ] Using latest version of package platformdirs: Version is 2.6.2; latest is 3.0.0
[ ] CPE name included for package platformdirs: MISSING
[ ] License included for package tomli: MISSING
[ ] SPDX Compatible License id included for package tomli: NOASSERTION
[ ] NTIA compliant : FAILED
╭───────────────────────╮
│ Relationships Summary │
╰───────────────────────╯
[x] Relationship Summary
╭──────────────╮
│ NTIA Summary │
╰──────────────╯
[ ] NTIA conformant : FAILED
╭────────────────────╮
│ SBOM Audit Summary │
╰────────────────────╯
[x] Checks passed 42
[x] Checks failed 12                                                   

Output File Format

The output file is in JSON format. The content depends on the contents of the SBOM and the specified command line options.

sbomaudit --input-file click.json --verbose --output-file click_analysis.json

As the --verbose option is specified, the resulting JSON file contains the results of all the checks which have been performed.

{
  "metadata": [
    {
      "text": "Up to date SPDX Version",
      "state": "Pass"
    },
    {
      "text": "SBOM Creator identified",
      "state": "Pass"
    },
    {
      "text": "SBOM Creation time defined",
      "state": "Pass"
    }
  ],
  "packages": [
    {
      "name": "click",
      "version": "8.0.3",
      "reports": [
        {
          "text": "Supplier included for package click",
          "state": "Pass"
        },
        {
          "text": "Version included for package click",
          "state": "Pass"
        },
        {
          "text": "License included for package click",
          "state": "Pass"
        },
        {
          "text": "SPDX Compatible License id included for package click",
          "state": "Pass"
        },
        {
          "text": "OSI Approved license for click",
          "state": "Pass"
        },
        {
          "text": "Non-deprecated license for click",
          "state": "Pass"
        },
        {
          "text": "Using latest version of package click: Version is 8.0.3; latest is 8.1.7",
          "state": "Fail"
        }
      ]
    }
  ],
  "policy": [
    {
      "text": "Using mature version of package click",
      "state": "Pass"
    },
    {
      "text": "Using old version of package click: Age of release is 928 days",
      "state": "Fail"
    }
  ],
  "relationships": [
    {
      "text": "Dependency relationships provided for NTIA compliance",
      "state": "Pass"
    },
    {
      "text": "Dependency relationship found for click",
      "state": "Pass"
    }
  ],
  "summary": [
    {
      "text": "NTIA conformant",
      "state": "Pass"
    },
    {
      "text": "Checks passed 13",
      "state": "Pass"
    },
    {
      "text": "Checks failed 1",
      "state": "Pass"
    },
    {
      "text": "Policy checks passed 1",
      "state": "Pass"
    },
    {
      "text": "Policy checks failed 1",
      "state": "Pass"
    }
  ]
}

Return Values

The following values are returned:

• -1 indicates SBOM file not specified
• 0 indicates NTIA compliance has failed
• 1 indicates NTIA compliance has passed

License

Licensed under the Apache 2.0 License.

Limitations

The tool has the following limitations:

• The latest version checks are only performed on Python modules available on the Python Package Index (PyPi).

• Invalid SBOMs will result in unpredictable results.

Feedback and Contributions

Bugs and feature requests can be made via GitHub Issues.