Getuidx64 Require Administrator Privileges Better -

| Scenario | Required Rights | Admin Needed? | |----------|----------------|----------------| | Query own current process token (limited user) | TOKEN_QUERY on self | ❌ No | | Query own token, then get linked UAC token | TOKEN_QUERY + SeTcbPrivilege | ✅ Yes | | Query another process owned by same user | PROCESS_QUERY_LIMITED_INFORMATION | ❌ No | | Query another process owned by different user (including SYSTEM) | PROCESS_QUERY_LIMITED_INFORMATION + SeDebugPrivilege or SeBackupPrivilege | ✅ Yes | | Query token of a process in another session (e.g., session 0 isolation) | Requires PROCESS_QUERY_LIMITED_INFORMATION + cross-session policy | ✅ Yes (admin or LocalSystem) | | Write to global cache file in ProgramData or C:\Windows | File write permissions | ✅ Yes (unless ACL modified) |

Running getuidx64 as a standard user is like trying to check the oil in a car without popping the hood. You might see the engine exists, but you cannot access the components to perform the actual measurement.

The requirement for Administrator privileges ensures: getuidx64 require administrator privileges better

Best Practice: Always run security auditing tools and low-level utilities via a Right-Click -> "Run as Administrator". This ensures the tool returns accurate, system-wide data rather than a sandboxed view of the user environment.

If you are working directly with x64 assembly, the system call numbers differ between getuid and geteuid. To check for admin privileges, you must use the geteuid syscall. | Scenario | Required Rights | Admin Needed

Here is a NASM snippet demonstrating how to check for root privileges via geteuid:

section .data
    msg_denied db "Access Denied: Root required.", 0xA
    len_denied equ $ - msg_denied
    msg_granted db "Access Granted.", 0xA
    len_granted equ $ - msg_granted
section .text
    global _start
_start:
    ; --- Perform geteuid syscall ---
    mov rax, 107        ; Syscall number for geteuid (Linux x64)
    syscall             ; Invoke kernel
; --- Check return value (stored in rax) ---
    test rax, rax       ; Compare rax with 0
    jne .not_root       ; If not 0, jump to not_root
.root:
    ; Logic for root user
    mov rax, 1          ; Syscall: write
    mov rdi, 1          ; File descriptor: stdout
    mov rsi, msg_granted
    mov rdx, len_granted
    syscall
; Exit cleanly
    mov rax, 60         ; Syscall: exit
    xor rdi, rdi        ; Status: 0
    syscall
.not_root:
    ; Logic for non-root user
    mov rax, 1          ; Syscall: write
    mov rdi, 1          ; File descriptor: stdout
    mov rsi, msg_denied
    mov rdx, len_denied
    syscall
; Exit with error
    mov rax, 60         ; Syscall: exit
    mov rdi, 1          ; Status: 1 (Error)
    syscall

| Feature | Unix/Linux | Windows NT (x64) | |---------|-------------|------------------| | User identifier | uid_t (integer) | SID (variable-length structure) | | Process token | Implicit per process | Explicit HANDLE to an ACCESS_TOKEN | | API to get caller’s UID | getuid() – no handle needed | OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, ...) | | Privilege required | None | TOKEN_QUERY – usually granted to all processes, but... | Best Practice: Always run security auditing tools and

The key nuance: TOKEN_QUERY is typically available to any process for its own token. So why does a custom getuidx64 sometimes require admin?