April 2019 Patch Tuesday

Welcome back to this month’s Patch Tuesday. This month includes patches for 70 vulnerabilities, including two which were actively being exploited in the wild. Both vulnerabilities are elevation of privilege vulnerabilities in win32k, allowing an unprivileged user to run arbitrary code in kernel mode. Other critical vulnerabilities resided in Microsoft’s browsers and in Office, allowing for remote code execution.

Internet Explorer and Edge

Microsoft’s browsers received the usual round of fixes this month for critical vulnerabilities. There were 8 critical vulnerabilities in the scripting engine used by Explorer and Edge, allowing for a remote attacker to execute code with security context equal to that of the current user.

Adobe Flash Player

Adobe Flash Player returns after its one-month hiatus to Patch Tuesday with a Use-After-Free vulnerability that was rated critical by Adobe, and an out-of-bounds read that would allow for local attackers to glean potentially sensitive information. As we approach 2020, where Adobe Flash Player will finally be put out to pasture, every month is a final countdown before users and developers finally are forced off the platform.

MS Office

Office patched 8 vulnerabilities this month, with one of them being rated critical. An attacker exploiting this vulnerability would have to lure the unsuspecting user into opening a maliciously crafted file. If successful, the attacker would gain privileges equal to that of the current user. This is once again a reminder to exercise the principal of least privilege (PoLP).

Windows Kernel

Windows Kernel received fixes for two vulnerabilities that were actively being exploited in the wild. These vulnerabilities are being exploited on older Windows platforms, but their latest Windows platforms are also vulnerable, and likely for exploit.

Team Foundation Server

Team Foundation Server received 9 fixes for vulnerabilities this month. None were rated critical, but attackers could execute arbitrary code and conduct cross-site scripting attacks on the Team Foundation Server. The attack would be a reflected cross site scripting attack, resulting in the exploit occurring every time a user visits the compromised page.