1. A host system comprising a hardware processor configured to operate: a virtual machine comprising a virtualized processor and a virtualized memory, the virtual machine configured to employ the virtualized processor to execute a target thread of a process; and a memory introspection engine executing outside the virtual machine and configured to: identify within a virtual memory space of the process a target page reserved for a call stack of the target thread; determine according to a page table of the virtual machine whether the target page is mapped to the virtualized memory; and in response to determining whether the target page is mapped to the virtualized memory, when the target page is not mapped to the virtualized memory: intercept an attempt to write to the target page, and in response to intercepting the attempt to write to the target page, prevent the virtualized processor from executing a content of the target page.