"Microsoft has patched flaws that attackers could exploit to compromise all Azure Red Hat Enterprise Linux (RHEL) instances.
Software engineer Ian Duffy found the flaws while building a secure RHEL image for Microsoft Azure. During that process he noticed an installation script Azure uses in its preconfigured RPM Package Manager contains build host information that allows attackers to find all four Red Hat Update Appliances which expose REST APIs over HTTPS.
From there Duffy found a package labelled PrepareRHUI (Red Hat Update Infrastructure) that runs on all Azure RHEL boxes, and contains the rhui-monitor.cloud build host."
Microsoft update servers left all Azure RHEL instances hackable