if (status == 0) ULONG connectivity = 0; ULONG returned = 0; status = NtQueryWnfStateData(hState, NULL, 0, &connectivity, sizeof(connectivity), &returned); if (status == 0) printf("Current network connectivity state: %lu\n", connectivity); // 0 = Unknown, 1 = No connectivity, 2 = Local, 3 = Internet
NTSTATUS NtQueryWnfStateData( _In_ HANDLE StateHandle, _In_opt_ PWNF_CHANGE_STAMP ChangeStamp, _Out_ PVOID Buffer, _In_ ULONG BufferSize, _Out_opt_ PULONG DataSize, _Out_opt_ PWNF_CHANGE_STAMP ChangeStampResult ); ntquerywnfstatedata ntdlldll better
ntdll.dll (NT Layer DLL) is a user-mode system library loaded into almost every Windows process. It acts as the gateway to the Windows kernel, exporting the so-called Native API (NTAPI) functions — low-level system call stubs that transition execution from user mode to kernel mode. Examples include NtCreateFile , NtReadVirtualMemory , and the subject of this article: NtQueryWnfStateData . if (status == 0) ULONG connectivity = 0;
NtQueryWnfStateData and ntdll.dll: Mastering the Windows Notification Facility NtQueryWnfStateData and ntdll
: Security researchers have historically looked at WNF functions like NtUpdateWnfStateData and NtQueryWnfStateData to understand kernel memory management and potential vulnerabilities (e.g., CVE-2021-31956). Troubleshooting ntdll.dll Crashes
If you ever need to query a WNF state name, remember: ntdll.dll holds the key, but respect the kernel’s boundaries. Use documented APIs whenever possible, and treat direct NT calls as a last resort or purely for investigative purposes.