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Security Advisories: GSA_kwCzR0hTQS12OG14LWhwMnEtZ3c4Nc4AA6CR

Golang SDK for Vela Insecure Variable Substitution

Impact

Vela pipelines can use variable substitution combined with insensitive fields like parameters, image and entrypoint to inject secrets into a plugin/image and — by using common substitution string manipulation — can bypass log masking and expose secrets without the use of the commands block. This unexpected behavior primarily impacts secrets restricted by the "no commands" option. This can lead to unintended use of the secret value, and increased risk of exposing the secret during image execution bypassing log masking.

Given by the following substitution examples:
using parameters

steps:
  - name: example
    image: <some plugin>
    secrets: [ example_secret ]
    parameters:
      example: $${EXAMPLE_SECRET}

using image tag

steps:
  - name: example
    image: <some plugin>:latest${EXAMPLE_SECRET}
    secrets: [ example_secret ]

using entrypoint as a shim for commands

steps:
  - name: example
    image: <some plugin>
    secrets: [ example_secret ]
    entrypoint:
      [
        "sh",
        "-c",
        "echo $EXAMPLE_SECRET",
      ]

To exploit this the pipeline author must be supplying the secrets to a plugin that is designed in such a way that will print those parameters in logs. Plugin parameters are not designed for sensitive values and are often intentionally printed throughout execution for informational/debugging purposes. Parameters should therefore be treated as insensitive.

While Vela provides secrets masking, secrets exposure is not entirely solved by the masking process. A docker image (plugin) can easily expose secrets if they are not handled properly, or altered in some way. There is a responsibility on the end-user to understand how values injected into a plugin are used. This is a risk that exists for many CICD systems (like GitHub Actions) that handle sensitive runtime variables. Rather, the greater risk is that users who restrict a secret to the "no commands" option and use image restriction can still have their secret value exposed via substitution tinkering, which turns the image and command restrictions into a false sense of security.

Patches

N/A

Workarounds

References

For more information

If you have any questions or comments about this advisory:

Affected products: go-vela/worker

Permalink: https://github.com/advisories/GHSA-v8mx-hp2q-gw85
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS12OG14LWhwMnEtZ3c4Nc4AA6CR
Source: GitHub Advisory Database
Origin: Unspecified
Severity: High
Classification: General
Published: about 1 month ago
Updated: about 1 month ago


CVSS Score: 7.7
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Identifiers: GHSA-v8mx-hp2q-gw85
References: Repository: https://github.com/go-vela/sdk-go
Blast Radius: 6.5

Affected Packages

go:github.com/go-vela/sdk-go
Dependent packages: 13
Dependent repositories: 7
Downloads:
Affected Version Ranges: <= 0.23.1
Fixed in: 0.23.2
All affected versions: 0.1.0, 0.1.1, 0.1.2, 0.1.3, 0.1.4, 0.2.0, 0.3.0, 0.4.0, 0.4.1, 0.4.2, 0.4.3, 0.5.0, 0.5.1, 0.5.2, 0.6.0, 0.7.0, 0.7.2, 0.7.3, 0.7.4, 0.8.0, 0.8.1, 0.9.0, 0.10.0, 0.10.1, 0.11.0, 0.12.0, 0.13.0, 0.13.1, 0.14.0, 0.15.0, 0.15.1, 0.16.0, 0.16.1, 0.16.2, 0.17.0, 0.18.0, 0.18.1, 0.19.0, 0.19.1, 0.19.2, 0.20.0, 0.20.1, 0.20.2, 0.20.3, 0.21.0, 0.22.0, 0.23.0, 0.23.1
All unaffected versions: 0.23.2, 0.23.3