May 2019 Patch Tuesday

Welcome back to this month’s Patch Tuesday. This month includes patches for 79 vulnerabilities, including one that is actively being exploited in the wild. There is also an advisory from Microsoft detailing a vulnerability in Intel CPU speculative execution that came to light only a few hours before the release of the patches. The new speculative execution vulnerability is dubbed “Zombieload” and is similar to “Spectre” and “Meltdown” from last year. Microsoft has released mitigation instructions for CVE-2019-0863, “Zombieload”, in it’s advisory (ADV190013).

Internet Explorer and Edge

Microsoft’s browsers came with their typical host of fixes this month. Several of these vulnerabilities were critically rated by Microsoft, allowing attackers to execute code remotely. Microsoft has rated these vulnerabilities as likely to be exploited on the latest software release. As usual, the attacks would have the security context of the current user, which means that exercising the principle of least privilege mitigates these vulnerabilities.

Adobe Flash Player

Adobe has released yet another patch for a critical vulnerability in Adobe Flash Player. A remote attacker can execute arbitrary code within the context of the current user. At this point, it is just a countdown of how many vulnerabilities will be patched in Flash before its support is killed. After support runs out in 2020, the remaining vulnerabilities will surely be pilfered and used to exploit those who are slow to migrate from this vulnerability-ridden software.

Office

Office products received the usual round of fixes. There were multiple vulnerabilities that can result in remote code execution across multiple products, all with the security context of the current user. Once again, this is a reminder to exercise the principle of least privilege with all your applications.

Windows Error Reporting

This month Microsoft released a patch for Windows Error Reporting that was actively being exploited in the wild. The vulnerability allowed attackers to elevate privileges to administrator level from normal user accounts. Details about the attacks in the wild are still being kept under wraps to protect the victims. Microsoft claims that the fix corrects the way that Windows Error Reporting handles files, indicating that most likely the attackers supply a maliciously-crafted file to elevate their privileges.

.NET

Microsoft’s .NET Framework received fixes for denial of service vulnerabilities as well. Attackers can send maliciously crafted requests to the vulnerable application and cause the application to cease functioning. Microsoft has rated these vulnerabilities as important, and with exploitation less likely.