Welcome back to this month’s Patch Tuesday. This is the last Patch Tuesday of this decade, and it seems only fitting that a zero-day vulnerability that was actively being exploited in the wild was patched. In total there were 2 advisories and updates for 36 vulnerabilities this month. Of these vulnerabilities, 7 are classified as Critical, 27 as Important, 1 as Moderate, and 1 as Low.
An elevation of privilege vulnerability exists in Windows when the Win32k component fails to properly handle objects in memory. An attacker exploiting this vulnerability would be able to elevate their privileges to kernel mode. This vulnerability was actively being exploited in the wild and was discovered by Kaspersky Labs. Microsoft has rated this vulnerability as Critical.
Microsoft’s Office applications come with a host of fixes this month. Attackers could gain access to sensitive information in Microsoft Access and Excel, and execute code remotely in PowerPoint with the security context of the current user. Microsoft rates these vulnerabilities as Important.
Microsoft Graphics Component
Microsoft’s handling of graphical objects comes under frequent attack since it runs in full kernel mode. In this case, embedded fonts are processed by the kernel. An attacker luring a victim to view content with a maliciously crafted embedded font could take total control of the system. Microsoft has rated this vulnerability (CVE-2019-1468) as Critical.
Multiple vulnerabilities for Visual Studio’s Git component were patched that could have allowed for remote code execution. An attacker exploiting this vulnerability would execute code with security context of the current user. This is a reminder to yet again practice the principle of least privilege.
Windows Hyper-V is vulnerable to a flaw in which code run on a guest operating system would be able to execute code on the host. This is particularly dangerous as it pertains to cloud environments using Hyper-V, since an attacker could potentially access virtualized machines belonging to others, and access or destroy everything on that particular host.