Last week, Matthias Gliwka, software developer and cyber security researcher, published a Medium article detailing something shocking: Microsoft was leaking TLS private keys in its cloud ERP product.
Gilwka wrote that when he was checking on a business-critical application via RDP, he found a valid TLS certificate hiding in plain sight. “This certificate is shared across all sandbox environments, even those hosted for other Microsoft customers,” wrote Gilwka. “It’s used to encrypt the web traffic between the users of the software and the server. All you need to extract this certificate is access to ANY sandbox environment.”
Gilwka immediately contacted the Microsoft Security Response Center via PGP-encrypted mail detailing the leak. Unfortunately, it took months for the issue to be acknowledged and fixed by Microsoft.
Ultimately, Gilwka’s experience underscores the importance of machine identity protection, especially in the cloud. Even major corporations like Microsoft struggle with securing their private keys and this problem is getting worse since machine identities in the cloud can change rapidly.
“Microsoft shows how hard it is to protect machine identities and illustrates how powerful they are,” said Kevin Bocek, chief security strategist for Venafi. “Like many other businesses, Microsoft has had vulnerabilities with machine identities in the past, including: leaking Xbox Live keys to the Internet and failing to stop an outage from an expired certificate”
Sadly, machine identity protection is not well understood in the industry and this may have played a factor in Microsoft’s slow response to the leak. “From the first notification to the company taking decisive action, it took months for Microsoft to fix this vulnerability,” continued Bocek. “It’s not clear if Microsoft really didn’t understand the vulnerability, didn’t realize the scope of problem, or couldn’t take direct action because they didn’t have the intelligence necessary to track down the problem. However, it was clear is this type of vulnerability existed across business-critical Internet services.”
Ultimately, organizations should learn from Gilwka’s disclosure. “Businesses need to take action to protect themselves from similar leaks,” concluded Bocek. “It’s imperative that organizations use automated controls to protect machine identities like TLS certificates.”