Microsoft cloud security is “grossly irresponsible" and mired in a "culture of toxic obfuscation.” Amit Yoran, chairman and CEO of Tenable

“To give you an idea of how bad this is, our team very quickly discovered authentication secrets to a bank,” Yoran wrote. “They were so concerned about the seriousness and the ethics of the issue that we immediately notified Microsoft.” He continued: “Did Microsoft quickly fix the issue that could effectively lead to the breach of multiple customers’ networks and services? Of course not. They took more than 90 days to implement a partial fix.

Microsoft has once again come under blistering criticism for the security practices of Azure and its other cloud offerings, with the CEO of security firm Tenable saying Microsoft is “grossly irresponsible" and mired in a "culture of toxic obfuscation.” The comments from Amit Yoran, chairman and CEO of Tenable, come six days after Sen. Ron Wyden (D-Ore.) blasted Microsoft for what he said were “negligent cybersecurity practices” that enabled hackers backed by the Chinese government to steal hundreds of thousands of emails from cloud customers, including officials in the US Departments of State and Commerce. Microsoft has yet to provide key details about the mysterious breach, which involved the hackers obtaining an extraordinarily powerful encryption key granting access to a variety of its other cloud services. The company has taken pains ever since to obscure its infrastructure’s role in the mass breach.

On Wednesday, Yoran took to LinkedIn to castigate Microsoft for failing to fix what the company said on Monday was a “critical” issue that gives hackers unauthorized access to data and apps managed by Azure AD, a Microsoft cloud offering for managing user authentication inside large organizations. Monday’s disclosure said that the firm notified Microsoft of the problem in March and that Microsoft reported 16 weeks later that it had been fixed. Tenable researchers told Microsoft that the fix was incomplete. Microsoft set the date for providing a complete fix to September 28.

“To give you an idea of how bad this is, our team very quickly discovered authentication secrets to a bank,” Yoran wrote. “They were so concerned about the seriousness and the ethics of the issue that we immediately notified Microsoft.” He continued: “Did Microsoft quickly fix the issue that could effectively lead to the breach of multiple customers’ networks and services? Of course not. They took more than 90 days to implement a partial fix – and only for new applications loaded in the service.” In response, Microsoft officials wrote: “We appreciate the collaboration with the security community to responsibly disclose product issues. We follow an extensive process involving a thorough investigation, update development for all versions of affected products, and compatibility testing among other operating systems and applications. Ultimately, developing a security update is a delicate balance between timeliness and quality, while ensuring maximized customer protection with minimized customer disruption.” Microsoft went on to say that the initial fix in June “mitigated the issue for the majority of customers” and “no customer action is required.”

In a separate email, Yoran responded: “It now appears that it’s either fixed, or we are blocked from testing. We don’t know the fix, or mitigation, so hard to say if it’s truly fixed, or Microsoft put a control in place like a firewall rule or ACL to block us. When we find vulns in other products, vendors usually inform us of the fix so we can validate it effectively. With Microsoft Azure that doesn’t happen, so it’s a black box, which is also part of the problem. The ‘just trust us’ lacks credibility when you have the current track record.”