Microsoft accidentally exposed Dynamics 365 TLS certificates exposing sandbox environments to MiTM attacks

Microsoft accidentally exposed a Dynamics 365 TLS certificate and private key for at least 100 days leaving the sandbox environments open to MiTM attacks.

Data leakage continues to represent a serious problem for organizations, now it’s up to Microsoft that accidentally exposed a Dynamics 365 TLS certificate and private key for at least 100 days.

The software developer Matthias Gliwka discovered the issue while working with the cloud version of the Microsoft ERP system.

Microsoft started offering the ERP product last year, it is SaaS solution hosted in Azure and accessible through a comprehensive control panel (Life Cycle Services).

According to Gliwka, the TLS certificate was exposed in the Dynamics 365 sandbox environment that is used for user acceptance testing (also referred to as “sandbox”) .

The user acceptance system mirrors the setup of the production environment with a single exception, it offers administrative RDP access.

The expert accessed a sandbox environment via RDP to learn how Microsoft would set up a server hosting such a business critical application.

“The hostname for a sandbox environment is customername.sandbox.operations.dynamics.com. A quick glance at the certificates inside the built-in “Certificate Manager” revealed something shocking” wrote Gliwka on Medium.

“Sitting there in plain sight was a valid TLS certificate for the common name *.sandbox.operations.dynamics.com and the corresponding private key — by the courtesy of Microsoft IT SSL SHA2 CA! This certificate is shared across all sandbox environments, even those hosted for other Microsoft customers.”

The certificate is used encrypt the web traffic between the users and the server, extracting the certificate an attacker could s access to any sandbox environment.

@msftsecresponse Reported a leaked TLS private key for a cloud product >45 days ago - still no response. Can you take a look? Case #40397

— Matthias Gliwka (@cerebuild) October 4, 2017

 

Gliwka reported the issue to Microsoft that took time to fix it, then he contacted German tech freelancer Hanno Böck to get coverage.

Böck tried filing a bug ticket with Mozilla’s bug tracker that triggered the Microsoft’s action.

The issue was solved on 5 December, months later it first notification on 17 August.