azure-appsvc-execute-as-via-deploy

Code/config modification on a site + the site runs as an MI => execute as that MI (via the MSI token endpoint).

derived azure emits CanExecuteAs

match

A conjunctive graph pattern. Variables (?x) bind node ids; every clause must hold.

where

optional

Present → upgrade the emitted state; absent → downgrade (not a hard requirement).

emit

source type	`Identity`
target type	`Identity`
source	`<principal>`
target	`<managed identity>`
permissions	`Microsoft.Web/sites/publish/action \| config/write \| extensions/write \| sourcecontrols/write \| functions/write`
state logic	if ?site running: ACTIVE elif matched(optional[0]): ACTIVE # attacker can start/restart it else: CONDITIONAL(service_state)

source type

Identity

target type

Identity

source

<principal>

target

<managed identity>

permissions

Microsoft.Web/sites/publish/action | config/write | extensions/write | sourcecontrols/write | functions/write

state logic

if ?site running: ACTIVE elif matched(optional[0]): ACTIVE # attacker can start/restart it else: CONDITIONAL(service_state)

Narrative

{principal.name} can deploy/modify code on {site.name} and mint the token of its identity {mi.name} from the App Service MSI endpoint, executing as {mi.name}.

Raw rule rules/derived/azure/appservice.yaml

id: azure-appsvc-execute-as-via-deploy
emits: CanExecuteAs
description: Code/config modification on a site + the site runs as an MI => execute as that MI (via the
  MSI token endpoint).
match:
- - principal: null
  - CanModifyCode
  - site: null
- - site: null
  - ExecutesAs
  - mi: null
where:
- node_type(?site) == ApplicationPlatform
- '?mi.privilege_level >= ?principal.privilege_level   # escalation only'
optional:
- - principal: null
  - CanStart
  - site: null
emit:
  source_type: Identity
  target_type: Identity
  source: <principal>
  target: <managed identity>
  state_logic: 'if ?site running: ACTIVE

    elif matched(optional[0]): ACTIVE   # attacker can start/restart it

    else: CONDITIONAL(service_state)

    '
  conditions_from:
  - site: null
  - mi: null
  permissions:
  - Microsoft.Web/sites/publish/action | config/write | extensions/write | sourcecontrols/write | functions/write
  derived_from:
  - <CanModifyCode edge_id>
  - <ExecutesAs edge_id>
  false_positive_note: Emit only when the site has a managed identity and that MI out-privileges the caller.
    On a stopped app without CanStart -> CONDITIONAL(service_state). CanModifyConfiguration (startup command)
    also satisfies this via the same fixpoint.
  narrative: '{principal.name} can deploy/modify code on {site.name} and mint the token of its identity
    {mi.name} from the App Service MSI endpoint, executing as {mi.name}.'