As of September 16, newly created Linux servers in Azure are still packaged with a vulnerable version of the OMI agent. After deploying a Linux server and enabling one the services listed above, the server will be in a vulnerable state.
The OMI server receives configuration management messages via the /wsman endpoint. Typically, an Authentication header is passed along with the message and the OMI server will ensure the client is authorized communicate. In this case the vulnerability is that when there is no Authentication header the server incorrectly accepts the message and executes the instruction under the root user.
By posting an “ExecuteShellCommand” SOAP payload to the server with no Authentication header specified, it will execute the command as root.