Windows Defender Application Control Security Feature Bypass Vulnerability

A security feature bypass vulnerability exists in Windows Defender Application Control (WDAC) which could allow an attacker to bypass WDAC enforcement. An attacker who successfully exploited this vulnerability could circumvent PowerShell Core Constrained Language Mode on the machine. To exploit the vulnerability, an attacker would first have administrator access to the local machine where PowerShell is running in Constrained Language mode. By doing that an attacker could access resources in an unintended way. The update addresses the vulnerability by correcting how PowerShell functions in Constrained Language Mode.