fleet/articles/vulnerability-processing.md

# Vulnerability processing

Vulnerability processing in Fleet detects vulnerabilities (CVEs) for the software installed on your hosts.

To see what software is covered, check out the [Coverage section](#coverage).

[Learn more](https://github.com/fleetdm/fleet/blob/main/docs/Contributing/guides/vulnerability-processing.md) about how it works for different platforms.

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## Coverage

Fleet detects vulnerabilities for these software types:

| Type                | macOS                                      | Windows                                          | Linux                                                                                                                                                                                                                                                                                                                                                  |
| ------------------- | ------------------------------------------ | ------------------------------------------------ |--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Apps                | ✅                                         | ✅                                               | ❌                                                                                                                                                                                                                                                                                                                                                      |
| Operating system (OS) | ✅                                         | ✅                                            | ✅                                                                                                                                                                                                                                                                                                                                                      |
| Browser plugins     | Chrome extensions, Firefox extensions      | Chrome extensions, Firefox extensions            | ❌                                                                                                                                                                                                                                                                                                                                                      |
| Packages            | Python, Homebrew  | Python, Atom, Chocolatey | <p>For Ubuntu, Debian, RHEL (including CentOS), and Fedora: packages defined in the [OVAL definitions](https://github.com/fleetdm/nvd/blob/master/oval_sources.json), except for vulnerabilities involving configuration files.</p><p>For Amazon Linux, packages maintained by Amazon by checking [ALAS advisories](https://alas.aws.amazon.com/).</p> |
| IDE extensions      | VS Code extensions | VS Code extensions | VS Code extensions                                                                                                                                                                                                                                                                                                                                     |

Linux OS vulnerabilites are the kernel vulnerabilities. Currently, Ubuntu, Debian, and Amazon Linux are supported. CentOS and Fedora [coming soon](https://github.com/fleetdm/fleet/issues/31495).

Linux kernel vulnerabilities with known variants (ie. `-generic` or `kernel`) are detected using OVAL. Custom kernels (unknown variants) are detected using NVD.

Currently, only software names with all ASCII characters are supported. Vulnerabilities won't be detected for software with names featuring non-ASCII characters, such as Cyrillic, or software that has been renamed from its default name (e.g. "Chrome 2" instead of "Google Chrome"). For some software, Fleet uses [custom rules](https://github.com/fleetdm/fleet/blob/main/server/vulnerabilities/nvd/cpe_translations.json) to mitigate these issues on an app-by-app basis.

If you find that Fleet is incorrectly marking software as vulnerable (false positive) or missing a vulnerability (false negative), please file a [bug](https://github.com/fleetdm/fleet/issues/new?template=bug-report.md). When false positives are fixed, it may take two hours for the false positive to disappear after upgrading Fleet.

## Sources

Fleet combines multiple sources to get accurate and up-to-date CVE information:
- [National Vulnerability Database](https://nvd.nist.gov/developers/vulnerabilities) CVE feeds
- [VulnCheck](https://vulncheck.com/) Enriched NVD CPE data
- [Mac Office release notes](https://learn.microsoft.com/en-us/officeupdates/release-notes-office-for-mac) Office for Mac vulnerabilities
- [Microsoft MSRC Security Bulletins](https://msrc.microsoft.com/update-guide) for Windows OS vulnerabilities
- [OVAL definitions](https://github.com/fleetdm/nvd/blob/master/oval_sources.json) for Linux software

> Fleet Premium includes CVSSv3 scores from NVD CVE feeds. Primary scores are preferred to Secondary scores
> if both are available, and v3.1 scores of the same type are preferred to v3.0.

## Advanced configuration

Fleet runs vulnerability downloading and processing via internal scheduled cron job. This internal mechanism is very useful
for frictionless deployments and is well suited for most use cases. However, in larger deployments,
where there can be dozens of Fleet server replicas sitting behind a load balancer, it is desirable to manage vulnerability processing externally.

The reasons for this are as follows:

- lower resource requirements across the entire Fleet server deployment (as vulnerability processing requires considerably more resources than just running Fleet server alone)
- more control over scheduling constraints (only process during windows of low utilization, etc.)

It is possible to limit vulnerability processing to a single [dedicated host](https://fleetdm.com/docs/deploying/configuration#current-instance-checks), by setting
`disable_schedule` to `true` but still run one Fleet server as `false`, but the drawback here is still having to dedicate resources
for this single host 24/7. The Fleet binary has a command which handles the same vulnerability processing, but will exit (successfully with 0) on completion. Using this sub-command we can delegate vulnerability processing
to external systems such as:

- [ECS](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/scheduling_tasks.html)
- [K8S](https://kubernetes.io/docs/tasks/job/automated-tasks-with-cron-jobs/)
- [GCP](https://cloud.google.com/run/docs/triggering/using-scheduler#create_job)
- [Plain old cron](https://en.wikipedia.org/wiki/Cron)

To opt into this functionality, be sure to configure your Fleet server deployment with

```bash
FLEET_VULNERABILITIES_DISABLE_SCHEDULE=true
```

which will **disable** the internal scheduling mechanism for vulnerability processing.

And then externally run with the same environment variables/configuration files passed to the server
command.

```text
fleet vuln_processing
```

<meta name="category" value="guides">
<meta name="authorGitHubUsername" value="noahtalerman">
<meta name="authorFullName" value="Noah Talerman">
<meta name="publishedOn" value="2024-07-12">
<meta name="articleTitle" value="Vulnerability processing">
<meta name="description" value="Find out how Fleet detects vulnerabilities and what software it covers.">