PS script to find files starting with certain Bytes

bytesearch.ps1

# Dir to search
$directory = "C:\Users\xxx\some_directory"

# Bytes to look for
$byteSequence = [byte[]](0xAF, 0x1B, 0xB1, 0xFA)

function Contains-ByteSequence {
    param (
        [string]$filePath,
        [byte[]]$sequence
    )

    try {
        $fileBytes = [System.IO.File]::ReadAllBytes($filePath)
        for ($i = 0; $i -le $fileBytes.Length - $sequence.Length; $i++) {
            if ($fileBytes[$i..($i + $sequence.Length - 1)] -eq $sequence) {
                return $true
            }
        }
    } catch {
        Write-Warning "Unable to read file: $filePath"
    }
    return $false
}

Get-ChildItem -Path $directory -Recurse -File | ForEach-Object {
    if (Contains-ByteSequence $_.FullName $byteSequence) {
        Write-Output "Match found in: $($_.FullName)"
    }
}