1. Purpose
The Software Dependency Inventory provides a structured record of software components and third-party dependencies used by the organization.
The inventory helps the organization identify:
- What software components are used
- Where they are used
- Who maintains them
- Which applications depend on them
- Which versions are deployed
- Whether dependencies are supported
- Whether known vulnerabilities exist
- Whether licenses create risks
- Whether dependencies are directly or indirectly introduced
- How security updates are managed
- What happens if a dependency becomes compromised or unsupported
The objective is to maintain visibility over the software supply chain and support vulnerability management, secure development, change management, and information-security risk management.
2. Scope
The inventory may cover:
- Open-source libraries
- Commercial libraries
- Frameworks
- Runtime components
- Operating-system packages
- Container images
- Container packages
- Third-party SDKs
- Software modules
- Package-manager dependencies
- Build dependencies
- Development dependencies
- CI/CD dependencies
- Plugins
- Browser/client libraries
- Third-party APIs
- External software services
- AI/ML libraries and models
- Infrastructure-as-Code modules
- Infrastructure plugins
- Deployment packages
- Internal reusable components
The scope should be based on the organization’s technology architecture and risk assessment.
3. Software Supply Chain Principle
The organization should maintain visibility across:
Application → Direct Dependency → Transitive Dependency → Version → Source → Vulnerability → Risk → Remediation → Verification
For example:
SaaS Application → Node.js Package → Package Version → Open-Source Repository → Known Vulnerability → Risk Assessment → Upgrade → Testing → Deployment
The organization should consider both direct and transitive dependencies where technically feasible.
4. Inventory Ownership
Responsibility for maintaining the inventory should be clearly defined.
| Role | Responsibility |
|---|---|
| Engineering | Maintains application dependency information |
| Developers | Identify dependencies introduced through development |
| DevOps | Manages build, deployment and container dependencies |
| Information Security | Reviews security vulnerabilities and risks |
| Application Owner | Owns application-level dependency risk |
| Procurement | Provides information on licensed/commercial software |
| Risk Owner | Accepts residual dependency risk where required |
Automated dependency-management tools may be used to reduce manual maintenance.
5. Software Dependency Inventory Fields
The following fields may be maintained in a spreadsheet, GRC platform, SBOM platform, repository, or other controlled system.
| Field | Description |
|---|---|
| Dependency ID | Unique identifier |
| Application ID | Application using the dependency |
| Application Name | Application name |
| Component Name | Dependency/component name |
| Component Type | Library/Framework/SDK/Container/API/etc. |
| Package Manager | npm/pip/Maven/NuGet/etc. |
| Version | Currently deployed version |
| Latest Approved Version | Approved/current target version |
| Direct/Transitive | Direct or transitive dependency |
| Source | Repository/vendor/source |
| Supplier/Maintainer | Maintainer or vendor |
| License | Applicable license |
| Support Status | Supported/Deprecated/EOL |
| Production Use | Yes/No |
| Development Use | Yes/No |
| Build Dependency | Yes/No |
| Runtime Dependency | Yes/No |
| Internet Exposure | Yes/No |
| Data Access | Type of data accessed |
| Privilege | Privilege level |
| Known Vulnerability | Yes/No |
| Vulnerability ID | CVE or other identifier, where applicable |
| Severity | As determined by approved methodology |
| Exploitability | Applicable assessment |
| Risk | Low/Medium/High/Critical |
| Remediation | Upgrade/Patch/Replace/Accept/etc. |
| Owner | Responsible owner |
| Target Date | Remediation target |
| Status | Open/In Progress/Resolved/Accepted |
| Last Reviewed | Review date |
| Evidence | Supporting evidence |
6. Application Identification
Each software dependency should be associated with the application, service, or product in which it is used.
Example:
| Application | Dependency | Version |
|---|---|---|
| Customer Portal | React | [Version] |
| Customer API | Node.js Package | [Version] |
| Authentication Service | OAuth SDK | [Version] |
| Reporting Service | Python Library | [Version] |
This prevents the organization from maintaining a list of components without knowing where those components actually operate.
7. Direct and Transitive Dependencies
The organization should distinguish between:
Direct Dependency
A component explicitly added by the development team.
Example:
Application → Express
Transitive Dependency
A component introduced by another dependency.
Example:
Application → Express → Dependency B → Dependency C
Transitive dependencies can create security risk even when developers did not directly select or install the component.
Where technically feasible, dependency-management or Software Composition Analysis tools should be used to identify them.
8. Version Management
The inventory should record the version of important dependencies.
The organization should monitor for:
- New versions
- Security patches
- Deprecated versions
- End-of-life versions
- Breaking changes
- Unsupported versions
- Security advisories
Production versions should be traceable to the corresponding source-code or deployment record where practical.
9. Vulnerability Management
Software dependencies should be evaluated for known security vulnerabilities.
Potential sources include:
- Vendor security advisories
- Package repositories
- Security advisories
- Vulnerability databases
- Software Composition Analysis tools
- Dependency scanners
- Container scanners
- Security testing
- Penetration testing
Where a vulnerability is identified, the organization should evaluate:
- Affected component
- Affected application
- Version
- Severity
- Exploitability
- Exposure
- Data affected
- Business impact
- Available patch
- Compensating controls
- Remediation timeline
10. Vulnerability Risk Treatment
A vulnerability should not be treated solely according to a generic severity number.
The organization should consider actual organizational context.
For example:
A high-severity vulnerability in an unused development dependency may have a different risk from the same vulnerability in an internet-facing production component.
Possible treatment options include:
- Upgrade
- Patch
- Replace
- Remove
- Disable affected functionality
- Apply compensating controls
- Increase monitoring
- Restrict exposure
- Risk acceptance
Risk acceptance should follow the organization’s approved risk-management process.
11. Software Component Approval
Organizations should establish appropriate rules for introducing new software dependencies.
Before introducing a significant dependency, consider:
- Business/technical need
- Security reputation
- Maintenance activity
- Support status
- Known vulnerabilities
- License
- Data access
- Privileges
- Internet exposure
- Supplier/maintainer
- Community/vendor support
- Compatibility
- Alternative components
High-risk dependencies should receive appropriate security review before production use.
12. Unsupported and End-of-Life Dependencies
The organization should identify dependencies that are:
- End-of-life
- Deprecated
- No longer maintained
- No longer supported
- Receiving no security fixes
Unsupported components should be evaluated for risk.
Where appropriate, the organization should:
- Upgrade
- Replace
- Remove
- Isolate
- Apply compensating controls
- Document and formally accept residual risk
13. Software Source and Provenance
Where appropriate, the organization should understand where software components originate.
Consider:
- Official repositories
- Approved vendors
- Internal repositories
- Package registries
- Container registries
- Source repositories
- Build artifacts
The organization should avoid introducing software from untrusted or unknown sources.
14. Software Integrity
Where appropriate, controls should be used to protect the integrity of software dependencies.
Examples include:
- Approved repositories
- Dependency locking
- Version pinning
- Hash verification
- Signed packages
- Trusted container images
- Protected build pipelines
- Access-controlled repositories
- Protected branches
- CI/CD security controls
The appropriate controls should be based on risk and technology.
15. Software Bill of Materials (SBOM)
For applications where software supply-chain visibility is important, the organization may maintain or generate an SBOM.
An SBOM may provide information such as:
- Component name
- Version
- Supplier
- Package identifier
- Dependency relationship
- License
- Vulnerability information
An SBOM can support:
- Vulnerability response
- Customer security requests
- Supply-chain risk management
- Incident investigation
- Software inventory
- Dependency analysis
An SBOM does not replace vulnerability management or risk assessment.
16. Container Dependencies
Where containers are used, the organization should consider:
- Base images
- Operating-system packages
- Application packages
- Third-party libraries
- Container image source
- Image vulnerabilities
- Image lifecycle
- Image scanning
- Image signing where applicable
- Approved registries
Example:
Application Container → Node.js Base Image → OS Packages → npm Dependencies
All relevant layers should be considered where technically feasible.
17. Infrastructure-as-Code Dependencies
Where Infrastructure-as-Code is used, dependencies may include:
- Terraform modules
- Providers
- CloudFormation components
- Helm charts
- Kubernetes packages
- Deployment scripts
- External modules
These components should be managed according to their security and operational risk.
18. CI/CD Dependencies
The software supply chain can also include dependencies within build and deployment pipelines.
Examples:
- Build plugins
- GitHub Actions
- CI/CD runners
- Deployment tools
- Package registries
- Build containers
- Security scanners
- Infrastructure providers
Important CI/CD dependencies should be reviewed because compromise of a build dependency could potentially affect software delivered to production.
19. Third-Party APIs
External APIs can also represent software dependencies.
The organization should consider:
- API provider
- API purpose
- Information exchanged
- Authentication method
- API credentials
- Availability
- Security requirements
- Rate limits
- Supplier dependency
- Failure impact
- Alternative arrangements
API keys and credentials should not be stored in the inventory.
20. AI and Machine-Learning Dependencies
Where AI/ML technology is used, the inventory may also include:
- AI libraries
- ML frameworks
- Models
- Model providers
- SDKs
- Model APIs
- Vector databases
- AI plugins
- AI development tools
The organization should consider:
- Source
- Version
- Security
- Data access
- Model provenance
- Vulnerabilities
- Licensing
- Privacy implications
- Third-party processing
- Supplier dependency
21. License Management
Where applicable, software dependencies should be reviewed for licensing considerations.
The organization may record:
- License type
- License restrictions
- Commercial requirements
- Attribution requirements
- Distribution requirements
- Legal review status
Security and license risks should be managed through the appropriate organizational processes.
22. Dependency Monitoring
The organization should establish appropriate monitoring for important dependencies.
Monitoring may identify:
- New vulnerabilities
- Security advisories
- Version updates
- End-of-life announcements
- Maintainer changes
- Repository changes
- Malicious package reports
- License changes
- Critical dependency changes
Automated alerts should be used where practical.
23. Change Management
Significant software dependency changes should follow the organization’s change-management process.
Examples:
- Major version upgrade
- Security patch
- Dependency replacement
- New critical dependency
- Removal of a critical dependency
- Change to production container
- Change to build pipeline dependency
Where appropriate, changes should include:
Change → Testing → Security Validation → Approval → Deployment → Verification
24. Emergency Security Updates
Where a dependency vulnerability creates significant risk, the organization may use its emergency change process.
The process should include:
- Vulnerability identification
- Risk assessment
- Affected systems identification
- Remediation decision
- Emergency testing
- Approval
- Deployment
- Verification
- Documentation
Emergency changes should still leave an appropriate audit trail.
25. AWS SaaS Startup Example
Consider a SaaS startup operating an application on AWS.
The application uses:
- Node.js
- React
- PostgreSQL driver
- AWS SDK
- Authentication SDK
- Logging library
- Container base image
- Terraform provider
- GitHub Actions
A simplified inventory could look like:
| ID | Application | Dependency | Version | Type | Production | Vulnerability | Status |
|---|---|---|---|---|---|---|---|
| SW-001 | Customer API | Node Package A | [Version] | Direct | Yes | No | Approved |
| SW-002 | Customer API | Package B | [Version] | Transitive | Yes | Yes | Remediation |
| SW-003 | Customer UI | React | [Version] | Direct | Yes | No | Approved |
| SW-004 | API Container | Base Image | [Version] | Container | Yes | No | Approved |
| SW-005 | CI/CD | GitHub Action | [Version] | Build | Yes | Yes | Review |
| SW-006 | Infrastructure | Terraform Provider | [Version] | IaC | Yes | No | Approved |
If a vulnerability is discovered in SW-002, the organization can determine:
Component → Application → Production Environment → Exposure → Data → Risk → Remediation → Verification
That is much stronger evidence than simply showing a generic vulnerability-scanning report.
26. Startup-Friendly Dependency Management
A startup does not necessarily need a large manual spreadsheet containing every minor component.
A practical approach is:
Tier 1 — Automated Inventory
Use:
- Package lock files
- Dependency scanners
- Container scanners
- SBOM generation
- Repository security tools
Tier 2 — Central Visibility
Maintain a central record of:
- Critical applications
- Important dependencies
- Production components
- Critical vulnerabilities
- Unsupported components
- High-risk third-party software
Tier 3 — Risk-Based Review
Focus manual review on:
- Internet-facing components
- Production dependencies
- Privileged components
- Security-sensitive libraries
- Authentication components
- Encryption components
- Critical infrastructure dependencies
- Components with sensitive data access
This reduces unnecessary administrative work while maintaining meaningful supply-chain visibility.
27. Relationship With Other ISMS Documents
| Document | Relationship |
|---|---|
| Asset Register | Identifies technology assets |
| Application Register | Identifies applications |
| ICT Dependency Register | Identifies broader technology dependencies |
| Supplier Register | Identifies external suppliers |
| Software Dependency Inventory | Identifies software components |
| Vulnerability Register | Tracks identified vulnerabilities |
| Risk Register | Tracks significant risks |
| Change Management | Controls dependency changes |
| Secure Development Policy | Defines development security requirements |
| Patch Management Procedure | Defines patching activities |
| SBOM | Provides software-component visibility |
| Incident Management | Handles dependency-related security incidents |
| Business Continuity | Addresses critical technology dependencies |
28. Required Evidence
Depending on the organization’s technology and risk, evidence may include:
- Software Dependency Inventory
- Dependency lock files
- SBOM
- Software Composition Analysis reports
- Vulnerability scan reports
- Container scan reports
- Security advisories
- Patch records
- Change records
- Pull requests
- Code-review records
- Dependency approval records
- Exception/risk-acceptance records
- End-of-life tracking
- License review records
29. Common Mistakes
Mistake 1 — Tracking Only Direct Dependencies
Transitive dependencies can also introduce vulnerabilities.
Mistake 2 — Tracking Component Names Without Versions
Security risk often depends on the exact version deployed.
Mistake 3 — Maintaining a Manual Spreadsheet Only
For modern applications, automated dependency discovery is generally more reliable.
Mistake 4 — Ignoring Build Dependencies
A compromised CI/CD dependency can create software supply-chain risk.
Mistake 5 — Treating CVSS as the Entire Risk Decision
Technical severity should be considered alongside exposure, exploitability, business impact, data, and compensating controls.
Mistake 6 — Not Connecting Vulnerabilities to Applications
Knowing that a package is vulnerable is less useful than knowing:
Which production application uses it and what information or service could be affected?
30. Quick Audit Checklist
An auditor may ask:
- Do you maintain visibility of software dependencies?
- How are dependencies identified?
- Do you track direct and transitive dependencies?
- Are production versions known?
- How are vulnerabilities identified?
- How quickly are important vulnerabilities assessed?
- How are dependency risks prioritized?
- How are unsupported dependencies identified?
- How are new dependencies approved?
- Are third-party packages obtained from trusted sources?
- How are container dependencies managed?
- How are CI/CD dependencies managed?
- Do you generate or maintain SBOMs where appropriate?
- How are dependency changes controlled?
- How are emergency security updates handled?
- Can you trace a vulnerable dependency to affected applications?
- Can you demonstrate remediation and verification?
31. Final Audit Trail
A mature software dependency-management process should demonstrate:
Dependency Identified
↓
Application Mapped
↓
Version Recorded
↓
Source/Provenance Identified
↓
Security Status Checked
↓
Vulnerability Identified
↓
Risk Assessed
↓
Treatment Selected
↓
Patch / Upgrade / Replace
↓
Testing Completed
↓
Deployment Verified
↓
Inventory Updated
Final Principle
A Software Dependency Inventory is not simply a list of packages.
Its real purpose is to provide traceability:
What software do we depend on → where is it used → which version is running → what risks affect it → who owns the risk → what action was taken → and how was remediation verified?
For a modern SaaS organization, combining automated dependency discovery, vulnerability monitoring, SBOM capability, risk assessment, and controlled remediation provides a practical way to manage software supply-chain security without creating unnecessary documentation.