Vendors are often criticized for being slow to respond to security reports, but that’s not the case today as Microsoft is being praised for its rapid response to a report from Google’s Project Zero.
Google Project Zero security researcher Tavis Ormandy is well-known for his technical skills and uncanny ability to find vulnerabilities in software that no one else can. Ormandy is also known for using Twitter to alert vendors and the general public about what he’s working on, which is what happened last Friday night (May 5), when he tweeted about a new flaw in Microsoft’s code.
“I think @natashenka (Natalie Silvanovich) and I just discovered the worst Windows remote code exec in recent memory. This is crazy bad,” Ormandy wrote.
Silvanovich is a great researcher in her own right and had previously been spending much of her time looking at vulnerabilities in Adobe software.
With a vulnerability reported late Friday, it seemed likely at the time of the Ormandy’s tweet that it would take Microsoft weeks, or perhaps even months, to fix the issue. As it turns out, it took only three days for Microsoft to respond and fix the issue, with a security advisory released on May 8.
The actual flaw is identified as CVE-2017-0290 and is a remote code execution flaw in Microsoft’s Malware Protection Engine.
“The update addresses a vulnerability that could allow remote code execution if the Microsoft Malware Protection Engine scans a specially crafted file,” Microsoft warns in its advisory. “An attacker who successfully exploited this vulnerability could execute arbitrary code in the security context of the LocalSystem account and take control of the system.”
In the Google Project Zero bug report, Ormandy wrote that “… vulnerabilities in MsMpEng (Microsoft’s Malware Protection Engine) are among the most severe possible in Windows, due to the privilege, accessibility, and ubiquity of the service.”
Ormandy and Silvanovich discovered a flaw in the NScript element of the mpengine component of MsMpEng.
“NScript is the component of mpengine that evaluates any filesystem or network activity that looks like JavaScript,” the Google report states. “To be clear, this is an unsandboxed and highly privileged JavaScript interpreter that is used to evaluate untrusted code, by default on all modern Windows systems. This is as surprising as it sounds.”
Microsoft and Google Project Zero have had their issues in the past about disclosure, and this certainly is not the first time that Ormandy reported a flaw to Microsoft. What is truly surprising though is how incredibly fast Microsoft dealt with the issue. Given the complexity of the code and of the release engineering process to get a fix out, I personally expected at least 60 days—if not more—before a fix would be made, and apparently I wasn’t the only one to be surprised at Microsoft’s response.
“Still blown away at how quickly @msftsecurity responded to protect users, can’t give enough kudos. Amazing,” Ormandy wrote.
