services / Azure / Web Apps Functions host function keys

Host-level function keys for a function app, bearer credentials valid across all functions in the app to authorize HTTP invocation.

Host-wide invocation credentials; invoking functions runs code under the app's (possibly managed) identity.

Microsoft.​Web/​sites/​host/​functionkeys/​write

PUTting a host-level function key sets a known credential valid across the whole app (durable backdoor / persistence), enabling repeated invocation as the app identity (lateral); overwriting an existing host key alters/revokes the legitimate credential (manipulation).

Risks

1. Data manipulation (HIGH)
2. Account persistence (BOOST)
3. Lateral movement (BOOST)

Scope: HIGH

This privilege may grant access to sensitive data from a single organizational function, or allow interruption of a service supporting a single organizational function.

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