Az - PostgreSQL Privesc

Reading time: 4 minutes

tip

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

Support HackTricks

PostgreSQL Privesc

For more information about SQL Database check:

Az - PostgreSQL

Microsoft.DBforPostgreSQL/flexibleServers/read && Microsoft.DBforPostgreSQL/flexibleServers/write

With this permission, you can create, update, or delete PostgreSQL Flexible Server instances on Azure. This includes provisioning new servers, modifying existing server configurations, decommissioning servers, or change the admin user's password.

bash
az postgres flexible-server create \
    --name <ServerName> \
    --resource-group <ResourceGroupName> \
    --location <Location> \
    --admin-user <AdminUsername> \
    --admin-password <AdminPassword> \
    --sku-name <SkuName> \
    --storage-size <StorageSizeInGB> \
    --tier <PricingTier> \
    --version <PostgreSQLVersion>

For example, this permissions allow changing the PostgreSQL password, usefull of course in case that PostgreSQL authentication is enabled.

bash
az postgres flexible-server update \
    --resource-group <resource_group_name> \
    --name <server_name> \
    --admin-password <password_to_update>

Furthermore, with the permissions you can enable the assigned identity, and operate with the managed identity attached to the server. Here you can find all the extensions that Azure PostgreSQL flexible server supports https://learn.microsoft.com/en-us/azure/cosmos-db/postgresql/reference-extensions. To be able to use these extensions some server parameters (azure.extensions) need to be changed. For example here with a managed identity that can access Azure Storage:

First we change the parameters and be sure the assigned identity is enabled:

bash
az postgres flexible-server parameter set \
  --resource-group <YourResourceGroupName> \
  --server-name <YourServerName> \
  --name azure.extensions \
  --value "AZURE_STORAGE"

az postgres flexible-server identity update \
    --resource-group <YourResourceGroupName> \
    --server-name <YourServerName> \
    --system-assigned Enabled
sql 

CREATE EXTENSION IF NOT EXISTS azure_storage;

CREATE EXTERNAL DATA SOURCE ManagedIdentity

SELECT azure_storage.account_add('<storage-account>', '<storage-key>');

SELECT *
FROM azure_storage.blob_get(
    '<storage-account>',
    '<container>',
    'message.txt',
    decoder := 'text'
) AS t(content text)
LIMIT 1;

Additionally it is necesary to have the public access enabled if you want to access from a non private endpoint, to enable it:

bash
az postgres flexible-server update --resource-group <resource_group_name> --server-name <server_name> --public-access Enabled

Microsoft.DBforPostgreSQL/flexibleServers/read, Microsoft.DBforPostgreSQL/flexibleServers/write, Microsoft.DBforPostgreSQL/flexibleServers/backups/read, Microsoft.ManagedIdentity/userAssignedIdentities/assign/action

With this permissions you can restore a server from a backup with:

bash
az postgres flexible-server restore \
  --resource-group <RESOURCE_GROUP> \
  --name <NEW_SERVER_NAME> \
  --source-server <SOURCE_SERVER_NAME> \
  --restore-time "<ISO8601_TIMESTAMP>" \
  --yes

Microsoft.DBforPostgreSQL/flexibleServers/read, Microsoft.DBforPostgreSQL/flexibleServers/write, Microsoft.ManagedIdentity/userAssignedIdentities/assign/action, Microsoft.DBforPostgreSQL/flexibleServers/administrators/write && Microsoft.DBforPostgreSQL/flexibleServers/administrators/read

With this permission, you can configure Azure Active Directory (AD) administrators for a PostgreSQL Flexible Server. This can be exploited by setting oneself or another account as the AD administrator, granting full administrative control over the PostgreSQL server. Updating existing principal is not supported yet so if there is one created you must delete it first.

It's important that the flexible-server has a user assigned managed identities to use.

bash
az postgres flexible-server ad-admin create \
    --resource-group <ResourceGroupName> \
    --server-name <ServerName> \
    --display-name <ADAdminDisplayName> \
    --identity <IdentityNameOrID> \
    --object-id <ObjectID>

tip

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

Support HackTricks