1. A method comprising employing at least one hardware processor of a host system to execute a memory introspection engine, the memory introspection engine executing outside of a virtual machine exposed by the host system, the virtual machine comprising a virtualized processor and a virtualized physical memory, the virtual machine configured to employ the virtualized processor to execute a target thread of a process, and wherein executing the memory introspection engine comprises: identifying within a virtual memory space of the process a target page reserved for a call stack of the target thread, wherein identifying the target page comprises determining an address of a top of the call stack, and determining whether the target page is reserved for the call stack according to the address; determining according to a page table of the virtual machine whether the target page is mapped to the virtualized physical memory; and in response to determining whether the target page is mapped to the virtualized physical memory, when the target page is not mapped to the virtualized physical memory: intercepting an attempt to write to the target page, and in response to intercepting the attempt to write to the target page, changing an access permission of the target page to indicate that the target page is non-executable.