How to manage third party software dependencies
When you develop and operate a service, it’s important to keep any third party dependencies you use up-to-date. By doing this, you can avoid potential security vulnerabilities.
Any automated tools you use to manage third party dependencies should be compatible with MHCLG supported programming languages. The tools you use should neither slow down your development process nor disclose potential security vulnerabilities to the public.
You can read more about managing software dependencies in the Service Manual, where you will find a list of common dependency management tools.
Some of our programming language style guides also contain language-specific advice about managing dependencies (for example, managing Python dependencies).
Update dependencies frequently
Update your dependencies frequently rather than in ‘big bang’ batches. This works well with continuous delivery principles and makes sure the changes introduced are small and can be automatically tested.
There are tools which scan GitHub repositories and raise pull requests (PRs) when they find dependency updates. Teams at MHCLG are using:
Dependabot - The GOV.UK docs contain guidance on using Dependabot and how the PRs raised should be reviewed
Renovate - used on Funding Service to do the same job as Dependabot - chosen in this instance because it supported
uvfor dependency management before dependabot.
All the above tools are free to use on public repositories.
Monitor for vulnerabilities
You should monitor for potential vulnerabilities in every layer of your technology stack. This is not straightforward but tooling exists to help. The Service Manual provides guidance on browser technology, tooling and mailing lists you can subscribe to.
Most of the tooling that helps you stay on top of dependency updates will also highlight vulnerabilities. Additional tooling includes:
GitHub security alerts
When GitHub discovers or is informed about a vulnerability, it will email an alert to the repository owner and users with admin access. GitHub security alerts will be turned on for all Alphagov repositories. If services wish to opt out of security advisories on their repository, they can contact Cyber Security and then add the no-security-advisories tag to their repository.
Managing Docker dependencies
Rebuild Docker base images
Like dependencies, Docker base images are also frequently updated. If you run containers as part of your service, you should regularly rebuild your images (and base images) to include the latest updates. Automate this process where possible.
Specifying Docker image tags
The MHCLG Way Dockerfile guidance contains advice on how to use Docker image tags to specify the exact container image version to use.
Use official Docker base images
Always use official base images. Docker Hub regularly scans official images and you can view the results by logging into Docker Hub. If you do not regularly update your base image, you must make sure a manual process exists to monitor and prioritise fixes for detected vulnerabilities.
Minimise what you need to monitor
Minimise the things you need to monitor by minimising dependencies where possible. For example, if running containers, make sure you pick the smallest base images.
Also consider managed solutions where possible. For example:
- Consider managed container orchestration technology such as AWS Fargate or similar so you do not have to monitor for vulnerabilities in your OS or control plane