# Kubernetes

!!! warning "EXPERIMENTAL"
    This feature might change without preserving backwards compatibility.

Trivy can connect to your Kubernetes cluster and scan it for security issues using the `trivy k8s` command. This page covers the technical capabilities of Trivy Kubernetes scanning.
Trivy can also be installed *inside* your cluster as a Kubernetes Operator, and continuously scan it. For more about this, please see the [Trivy Operator][https://aquasecurity.github.io/trivy-operator/] project.

When scanning a Kubernetes cluster, Trivy differentiates between the following:

1. Cluster infrastructure (e.g api-server, kubelet, addons)
1. Cluster configuration (e.g Roles, ClusterRoles). 
1. Application workloads (e.g nginx, postgresql).

When scanning any of the above, the container image is scanned separately to the Kubernetes resource definition (the YAML manifest) that defines the resource.

Container image is scanned for:
- Vulnerabilities
- Misconfigurations
- Exposed secrets

Kubernetes resource definition is scanned for:
- Vulnerabilities - partially supported through [KBOM scanning](#KBOM)
- Misconfigurations
- Exposed secrets

## Kubernetes target configurations

Trivy follows the behavior of the `kubectl` tool as much as possible.

### Scope

The command expects an argument that selects the scope of the scan (similarly to how `kubectl` expects an argument after `kubectl get`). This argument can be:
1. A Kubernetes Kind. e.g `pod`, `deployment`, etc. 
2. A Kubernetes Resource. e.g `pods/mypod`, etc.
3. `all`. Scan common workload kinds, as listed [here](https://github.com/aquasecurity/trivy-kubernetes/blob/bf8cc2a00d9772e0aa271f06d375b936152b54b1/pkg/k8s/k8s.go#L296:L314)
4. `cluster` scan the entire cluster including all namespaced resources and cluster level resources.

Examples:

```
trivy k8s all
trivy k8s pods
trivy k8s deploy myapp
trivy k8s pod/mypod
trivy k8s pods,deploy
trivy k8s cluster
```

Note that the scope argument must appear last in the command line, after any other flag.

### Cluster

By default Trivy will look for a [`kubeconfig` configuration file in the default location](https://kubernetes.io/docs/concepts/configuration/organize-cluster-access-kubeconfig/), and use the default cluster that is specified.  
You can also specify a `kubeconfig` using the `--kubeconfig` flag:

```
trivy k8s --kubeconfig ~/.kube/config2
```

### Namespace

By default Trivy will scan all namespaces (following `kubectl` behavior). To specify a namespace use the `--namespace` flag:

```
trivy k8s --kubeconfig ~/.kube/config2 --namespace default
```
### Node

You can exclude specific nodes from the scan using the `--exclude-nodes` flag, which takes a label in the format `label-name:label-value` and excludes all matching nodes:

```
trivy k8s cluster --report summary --exclude-nodes kubernetes.io/arch:arm6
```

### Components types

You can control what kinds of components are discovered using the `--components` flag:
- `--components infra` will discover only cluster infrastructure components.
- `--components workloads` will discover only application workloads.
- If the flag is omitted: infra, workloads, and RBAC are discovered.

## Reporting and filtering

Since scanning an entire cluster for any security issue can be overwhelming, By default Trivy summarizes the results in a simple "summary" view.
By scoping the scan on a specific resource, you can see the detailed report.
You can always choose the report granularity using the `--report summary`/`--report all` flag.

Scan a full cluster and generate a simple summary report:

```
$ trivy k8s --report=summary cluster
```

![k8s Summary Report](https://github.com/aquasecurity/trivy/raw/main/docs/imgs/trivy-k8s.png)

Filter by severity:

```
trivy k8s --severity=CRITICAL --report=all cluster
```

Filter by scanners (Vulnerabilities, Secrets or Misconfigurations):

```
trivy k8s --scanners=secret --report=summary cluster
# or
trivy k8s --scanners=config --report=summary cluster
```

The supported output formats are `table`, which is the default, and `json`.

```
trivy k8s --format json -o results.json cluster
```

<details>
<summary>Result</summary>

```json
{
  "ClusterName": "minikube",
  "Vulnerabilities": [
    {
      "Namespace": "default",
      "Kind": "Deployment",
      "Name": "app",
      "Results": [
        {
          "Target": "ubuntu:latest (ubuntu 22.04)",
          "Class": "os-pkgs",
          "Type": "ubuntu",
          "Vulnerabilities": [
            {
              "VulnerabilityID": "CVE-2016-2781",
              "PkgName": "coreutils",
              "InstalledVersion": "8.32-4.1ubuntu1",
              "Layer": {
                "Digest": "sha256:125a6e411906fe6b0aaa50fc9d600bf6ff9bb11a8651727ce1ed482dc271c24c",
                "DiffID": "sha256:e59fc94956120a6c7629f085027578e6357b48061d45714107e79f04a81a6f0c"
              },
              "SeveritySource": "ubuntu",
              "PrimaryURL": "https://avd.aquasec.com/nvd/cve-2016-2781",
              "DataSource": {
                "ID": "ubuntu",
                "Name": "Ubuntu CVE Tracker",
                "URL": "https://git.launchpad.net/ubuntu-cve-tracker"
              },
              "Title": "coreutils: Non-privileged session can escape to the parent session in chroot",
              "Description": "chroot in GNU coreutils, when used with --userspec, allows local users to escape to the parent session via a crafted TIOCSTI ioctl call, which pushes characters to the terminal's input buffer.",
              "Severity": "LOW",
              "CweIDs": [
                "CWE-20"
              ],
              "VendorSeverity": {
                "cbl-mariner": 2,
                "nvd": 2,
                "redhat": 2,
                "ubuntu": 1
              },
              "CVSS": {
                "nvd": {
                  "V2Vector": "AV:L/AC:L/Au:N/C:N/I:P/A:N",
                  "V3Vector": "CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N",
                  "V2Score": 2.1,
                  "V3Score": 6.5
                },
                "redhat": {
                  "V2Vector": "AV:L/AC:H/Au:N/C:C/I:C/A:C",
                  "V3Vector": "CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H",
                  "V2Score": 6.2,
                  "V3Score": 8.6
                }
              },
              "References": [
                "http://seclists.org/oss-sec/2016/q1/452",
                "http://www.openwall.com/lists/oss-security/2016/02/28/2",
                "http://www.openwall.com/lists/oss-security/2016/02/28/3",
                "https://access.redhat.com/security/cve/CVE-2016-2781",
                "https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-2781",
                "https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772@%3Cdev.mina.apache.org%3E",
                "https://lore.kernel.org/patchwork/patch/793178/",
                "https://nvd.nist.gov/vuln/detail/CVE-2016-2781"
              ],
              "PublishedDate": "2017-02-07T15:59:00Z",
              "LastModifiedDate": "2021-02-25T17:15:00Z"
            }
          ]
        }
      ]
    }
  ],
  "Misconfigurations": [
    {
      "Namespace": "default",
      "Kind": "Deployment",
      "Name": "app",
      "Results": [
        {
          "Target": "Deployment/app",
          "Class": "config",
          "Type": "kubernetes",
          "MisconfSummary": {
            "Successes": 20,
            "Failures": 19,
            "Exceptions": 0
          },
          "Misconfigurations": [
            {
              "Type": "Kubernetes Security Check",
              "ID": "KSV001",
              "Title": "Process can elevate its own privileges",
              "Description": "A program inside the container can elevate its own privileges and run as root, which might give the program control over the container and node.",
              "Message": "Container 'app' of Deployment 'app' should set 'securityContext.allowPrivilegeEscalation' to false",
              "Namespace": "builtin.kubernetes.KSV001",
              "Query": "data.builtin.kubernetes.KSV001.deny",
              "Resolution": "Set 'set containers[].securityContext.allowPrivilegeEscalation' to 'false'.",
              "Severity": "MEDIUM",
              "PrimaryURL": "https://avd.aquasec.com/misconfig/ksv001",
              "References": [
                "https://kubernetes.io/docs/concepts/security/pod-security-standards/#restricted",
                "https://avd.aquasec.com/misconfig/ksv001"
              ],
              "Status": "FAIL",
              "Layer": {},
              "IacMetadata": {
                "Provider": "Kubernetes",
                "Service": "general",
                "StartLine": 121,
                "EndLine": 133
              }
            },
            {
              "Type": "Kubernetes Security Check",
              "ID": "KSV003",
              "Title": "Default capabilities not dropped",
              "Description": "The container should drop all default capabilities and add only those that are needed for its execution.",
              "Message": "Container 'app' of Deployment 'app' should add 'ALL' to 'securityContext.capabilities.drop'",
              "Namespace": "builtin.kubernetes.KSV003",
              "Query": "data.builtin.kubernetes.KSV003.deny",
              "Resolution": "Add 'ALL' to containers[].securityContext.capabilities.drop.",
              "Severity": "LOW",
              "PrimaryURL": "https://avd.aquasec.com/misconfig/ksv003",
              "References": [
                "https://kubesec.io/basics/containers-securitycontext-capabilities-drop-index-all/",
                "https://avd.aquasec.com/misconfig/ksv003"
              ],
              "Status": "FAIL",
              "Layer": {},
              "IacMetadata": {
                "Provider": "Kubernetes",
                "Service": "general",
                "StartLine": 121,
                "EndLine": 133
              }
            }
          ]
        }
      ]
    },
    {
      "Namespace": "default",
      "Kind": "ConfigMap",
      "Name": "kube-root-ca.crt"
    }
  ]
}

```

</details>

## Compliance
This section describes Kubernetes specific compliance reports.
For an overview of Trivy's Compliance feature, including working with custom compliance, check out the [Compliance documentation](../compliance/compliance.md).

The following reports are available out of the box:

| Compliance                                   | Name for command     | More info                                                                                                           |
|----------------------------------------------|----------------------|---------------------------------------------------------------------------------------------------------------------|
| NSA, CISA Kubernetes Hardening Guidance v1.2 | `k8s-nsa`            | [Link](https://media.defense.gov/2022/Aug/29/2003066362/-1/-1/0/CTR_KUBERNETES_HARDENING_GUIDANCE_1.2_20220829.PDF) |
| CIS Benchmark for Kubernetes v1.23           | `k8s-cis`            | [Link](https://www.cisecurity.org/benchmark/kubernetes)                                                             |
| Pod Security Standards, Baseline             | `k8s-pss-baseline`   | [Link](https://kubernetes.io/docs/concepts/security/pod-security-standards/#baseline)                               |
| Pod  Security Standards, Restricted          | `k8s-pss-restricted` | [Link](https://kubernetes.io/docs/concepts/security/pod-security-standards/#restricted)                             |

Examples:

Scan the cluster for Kubernetes Pod Security Standards Baseline compliance:

```
trivy k8s cluster --compliance=k8s-pss-baseline --report summary
```

Get the detailed report for checks:

```
trivy k8s cluster --compliance=k8s-cis --report all
```

Get summary report in JSON format:

```
trivy k8s cluster --compliance=k8s-cis --report summary --format json
```

Get detailed report in JSON format:

```
trivy k8s cluster --compliance=k8s-cis --report all --format json
```

## KBOM

KBOM, Kubernetes Bill of Materials, is a manifest of all the important components that make up your Kubernetes cluster – Control plane components, Node Components, and Addons, including their versions and images. Which “api-server” version are you currently running? Which flavor of "kubelet" is running on each node? What kind of etcd or storage are you currently using? And most importantly – are there any vulnerabilities known to affect these components? These are all questions that KBOM can help you answer.  
For more background on KBOM, see [here](https://blog.aquasec.com/introducing-kbom-kubernetes-bill-of-materials).

Trivy can generate KBOM in CycloneDX format:

```sh
trivy k8s cluster --format cyclonedx --output mykbom.cdx.json
```

Trivy can also scan that generated KBOM (or any SBOM) for vulnerabilities:

```sh
trivy sbom mykbom.cdx.json
```

<details>
<summary>Result</summary>

```
2023-09-28T22:52:25.707+0300    INFO    Vulnerability scanning is enabled
 2023-09-28T22:52:25.707+0300    INFO    Detected SBOM format: cyclonedx-json
 2023-09-28T22:52:25.717+0300    WARN    No OS package is detected. Make sure you haven't deleted any files that contain information about the installed packages.
 2023-09-28T22:52:25.717+0300    WARN    e.g. files under "/lib/apk/db/", "/var/lib/dpkg/" and "/var/lib/rpm"
 2023-09-28T22:52:25.717+0300    INFO    Detected OS: debian gnu/linux
 2023-09-28T22:52:25.717+0300    WARN    unsupported os : debian gnu/linux
 2023-09-28T22:52:25.717+0300    INFO    Number of language-specific files: 3
 2023-09-28T22:52:25.717+0300    INFO    Detecting kubernetes vulnerabilities...
 2023-09-28T22:52:25.718+0300    INFO    Detecting gobinary vulnerabilities...
 Kubernetes (kubernetes)
 Total: 2 (UNKNOWN: 0, LOW: 1, MEDIUM: 0, HIGH: 1, CRITICAL: 0)
 ┌────────────────┬────────────────┬──────────┬────────┬───────────────────┬─────────────────────────────────┬──────────────────────────────────────────────────┐
 │    Library     │ Vulnerability  │ Severity │ Status │ Installed Version │          Fixed Version          │                      Title                       │
 ├────────────────┼────────────────┼──────────┼────────┼───────────────────┼─────────────────────────────────┼──────────────────────────────────────────────────┤
 │ k8s.io/kubelet │ CVE-2021-25749 │ HIGH     │ fixed  │ 1.24.0            │ 1.22.14, 1.23.11, 1.24.5        │ runAsNonRoot logic bypass for Windows containers │
 │                │                │          │        │                   │                                 │ https://avd.aquasec.com/nvd/cve-2021-25749       │
 │                ├────────────────┼──────────┤        │                   ├─────────────────────────────────┼──────────────────────────────────────────────────┤
 │                │ CVE-2023-2431  │ LOW      │        │                   │ 1.24.14, 1.25.9, 1.26.4, 1.27.1 │ Bypass of seccomp profile enforcement            │
 │                │                │          │        │                   │                                 │ https://avd.aquasec.com/nvd/cve-2023-2431        │
 └────────────────┴────────────────┴──────────┴────────┴───────────────────┴─────────────────────────────────┴──────────────────────────────────────────────────┘
```

</details>

Find more in the [documentation for SBOM scanning](./sbom.md).

Currently KBOM vulnerability matching works for plain Kubernetes distributions and does not work well for vendor variants, including some cloud managed distributions.
