PowerShell switch statement not working in TCP/UDP port scanner - powershell

Question

I am a PowerShell newbie trying to make a TCP and UDP port scanner. My code has a switch statement, where if you press 1 and enter that goes to the TCP function, 2 and enter the UDP function, or Q to quit it.
The issue is that the switch doesn't work properly. If you press 1 for TCP that just gives you the syntax prompt and asks you to press enter, then just ends the script - the same for TCP option 2. The Q button to quit works fine.
Can someone help? I can't spot what is wrong. My code is below
Thank you
Write-Host "Port Scanner"
function Show-Menu
{
param (
[string]$Title = 'Options'
)
Clear-Host
Write-Host "================ $Title ================"
Write-Host "1: Press '1' for TCP."
Write-Host "2: Press '2' for UDP."
Write-Host "Q: Press 'Q' to quit."
}
do
{
Show-Menu
$selection = Read-Host "Make a selection"
switch ($selection)
{
'1' {
Write-Host "To scan for open ports, run the following command: scan-port [devicename] -ports"
Function Scan-Port {
Param([string]$computername=$env:computername,
[array]$ports=#("21","22","23","25","80","443","3389")
)
#turn off error pipeline
$ErrorActionPreference = "SilentlyContinue"
#set values for Write-Progress
$activity="Port Scan"
$status="Scanning $computername"
$i=0
foreach ($port in $ports){
$i++
Write-Progress -Activity $activity -status $status `
-currentoperation "port $port" -percentcomplete (($i/$ports.count)*100)
#create empty custom object
$obj=New-Object PSObject
$obj | Add-Member -MemberType Noteproperty -name "Computername" -value $computername.ToUpper()
$obj | Add-Member -MemberType Noteproperty -name "Port" -value $port
$tcp=New-Object System.Net.Sockets.TcpClient($computername, $port)
if ($tcp.client.connected) {
$obj | Add-Member -MemberType Noteproperty -name "PortOpen" -value $True
[string]$rep=$tcp.client.RemoteEndPoint
[string]$ip=$rep.substring(0,$rep.indexof(":"))
}
else {
# Write-Warning "$computername not open on port: $port"
$obj | Add-Member -MemberType Noteproperty -name "PortOpen" -value $False
} #end Else
write $obj
$obj | Export-Csv -Append -path '.\PortScanResults.csv' -Delimiter ";" -Force
#disconnect the socket connection
$tcp.client.disconnect($False)
} #end foreach
#dispose and disconnect
$tcp.close()
Write-Progress -Activity $activity -status "Complete" -Completed
} #end function
} '2' {
Function port-scan-udp {
param($hosts,$ports)
if (!$ports) {
Write-Host "usage: test-port-udp <host|hosts> <port|ports>"
Write-Host " e.g.: test-port-udp 192.168.1.2 445`n"
return
}
$out = ".\scanresults.txt"
foreach($p in [array]$ports) {
foreach($h in [array]$hosts) {
$x = (gc $out -EA SilentlyContinue | select-string "^$h,udp,$p,")
if ($x) {
gc $out | select-string "^$h,udp,$p,"
continue
}
$msg = "$h,udp,$p,"
$u = new-object system.net.sockets.udpclient
$u.Client.ReceiveTimeout = 500
$u.Connect($h,$p)
# Send a single byte 0x01
[void]$u.Send(1,1)
$l = new-object system.net.ipendpoint([system.net.ipaddress]::Any,0)
$r = "Filtered"
try {
if ($u.Receive([ref]$l)) {
# We have received some UDP data from the remote host in return
$r = "Open"
}
} catch {
if ($Error[0].ToString() -match "failed to respond") {
# We haven't received any UDP data from the remote host in return
# Let's see if we can ICMP ping the remote host
if ((Get-wmiobject win32_pingstatus -Filter "address = '$h' and Timeout=1000 and ResolveAddressNames=false").StatusCode -eq 0) {
# We can ping the remote host, so we can assume that ICMP is not
# filtered. And because we didn't receive ICMP port-unreachable before,
# we can assume that the remote UDP port is open
$r = "Open"
}
} elseif ($Error[0].ToString() -match "forcibly closed") {
# We have received ICMP port-unreachable, the UDP port is closed
$r = "Closed"
}
}
$u.Close()
$msg += $r
Write-Host "$msg"
echo $msg >>$out
}
}
}
}
}
pause
}
until ($selection -eq 'q')

Answer 1

I have another issue I am hoping you can help with. The TCP bit now works but the UDP scanner isn't accepting any paramaters. If I put in the syntax and then press Enter nothing happens. Thanks
} '2' {
Function portudp {
Param($hosts,$ports)
if (!$ports) {
Write-Host "usage: portudp <host|hosts> <port|ports>"
Write-Host " e.g.: portudp 192.168.1.2 445`n"
return
}
$out = ".\scanresults.txt"
foreach($p in [array]$ports) {
foreach($h in [array]$hosts) {
$x = (gc $out -EA SilentlyContinue | select-string "^$h,udp,$p,")
if ($x) {
gc $out | select-string "^$h,udp,$p,"
continue
}
$msg = "$h,udp,$p,"
$u = new-object system.net.sockets.udpclient
$u.Client.ReceiveTimeout = 500
$u.Connect($h,$p)
# Send a single byte 0x01
[void]$u.Send(1,1)
$l = new-object system.net.ipendpoint([system.net.ipaddress]::Any,0)
$r = "Filtered"
try {
if ($u.Receive([ref]$l)) {
# We have received some UDP data from the remote host in return
$r = "Open"
}
} catch {
if ($Error[0].ToString() -match "failed to respond") {
# We haven't received any UDP data from the remote host in return
# Let's see if we can ICMP ping the remote host
if ((Get-wmiobject win32_pingstatus -Filter "address = '$h' and Timeout=1000 and ResolveAddressNames=false").StatusCode -eq 0) {
# We can ping the remote host, so we can assume that ICMP is not
# filtered. And because we didn't receive ICMP port-unreachable before,
# we can assume that the remote UDP port is open
$r = "Open"
}
} elseif ($Error[0].ToString() -match "forcibly closed") {
# We have received ICMP port-unreachable, the UDP port is closed
$r = "Closed"
}
}
$u.Close()
$msg += $r
Write-Host "$msg"
echo $msg >>$out
$out | Export-Csv -Append -path '.\UDPPPortScanResults.csv' -Delimiter ";" -Force
}
}
}
portudp
}
}
pause
}
until ($selection -eq 'q')
UDP Function Output