CLI Handbook¶

Goal¶

This is more or less a personal reference with useful CLI functions and commands.

Generally, everything is tested, but stuff breaks or changes with versions. Feedback or other recommendations are welcome!

The format is still work in progress and will change over time. Time will tell.

Things I try to focus on: - board tools prefered - one-liners - simplicity - reference to official docs - showing results

This is a living document! Tips are getting added, format changes, etc pp

Network¶

Check for open network port on host¶

Linux

Note: ss is being used on modern systems as netstat is deprecated.

# Specific Port (TCP/UDP)
ss -tupln | grep :443

# ON OLDER SYSTEMS
netstat -tupln | grep :443
or
netstat -anu | grep 51820 # TESTING

Windows/Powershell

TESTING

# TCP
Get-NetTCPConnection -State Listen
Get-NetTCPConnection -LocalPort 51820 

# UDP
Get-NetUDPEndpoint | Where-Object { $_.LocalPort -eq 51820 }

Windows/Command Line

# TCP
netstat -an | findstr LISTENING
netstat -ano | findstr ":51820"

# UDP
netstat -ano -p udp | find ":51820"

TCP Connectivity¶

Linux/netcat

# LISTENER
nc -l -p 443

# SENDER
nc -vz example.com 443

Windows/Test-NetConnection

# LISTENER
$l=[Net.Sockets.TcpListener]::new([Net.IPAddress]::Any,443);$l.Start();$c=$l.AcceptTcpClient();$s=$c.GetStream();$b=New-Object byte[] 4096;while(($n=$s.Read($b,0,$b.Length)) -gt 0){[Console]::OpenStandardOutput().Write($b,0,$n)};$s.Close();$c.Close();$l.Stop()

# SENDER
Test-NetConnection -ComputerName "example.com" -Port 443

# SHORT
tnc example.com -port 443

UDP Connectivity¶

A way to check connectivity between hosts via UDP.

Linux - netcat

# LISTENER
nc -u -l -p 51820

# SENDER
echo "hello" | nc -u 192.168.1.50 51820

Windows - Powershell

# LISTENER
$u=New-Object System.Net.Sockets.UdpClient 51820;while($true){$r=$u.Receive([ref]([System.Net.IPEndPoint]::new([System.Net.IPAddress]::Any,0)));[Text.Encoding]::UTF8.GetString($r)|Write-Host}

# SENDER
$u=New-Object System.Net.Sockets.UdpClient; $d=[Text.Encoding]::UTF8.GetBytes("hello");$u.Send($d,$d.Length,"192.168.1.50",51820)

Show Routing Table¶

Windows/Command Line

route print
route PRINT | findstr 198.51.100.55

Host¶

Timer or timeout for command¶

Linux

timeout --signal=TERM --kill-after=5s 60s ping 127.1

Certificates¶

Fetch remote certificate¶

Linux/openssl

openssl s_client -connect uphillsecurity.com:443 -showcerts </dev/null

Follow all HTTP 301/302 redirects and show headers¶

Linux/curl

curl -L -v -o /dev/null http://uphillsecurity.com

Protocol Headers¶

Fetch remote protocol headers¶

Linux/curl

curl -sIL http://uphillsecurity.com

Hashing¶

Produce Hash¶

Get hashes via Cyberchef here

Linux

# FILE
sha256sum /path/file | cut -d' ' -f1

# STRING
printf %s 'hello' | sha256sum | cut -d' ' -f1

# OPTIONS sha256sum, md5sum, sha1sum, sha512sum

Windows

Powershell

 Get-FileHash .\2025-01-03_00-55-22.png -Algorithm sha256 | fl

Algorithm : SHA256
Hash      : 3F1F067ADC45E49128033561018CCB8C9B79C655A65700BC425F1171F9255711
Path      : C:\Users\user\Documents\2025-01-03_00-55-22.png

# DEFAULT SHA256 -Algorithm SHA256|SHA1|SHA512|MD5

Commandline

certutil -hashfile ./2025-01-03_00-55-22.png sha256

SHA256 hash of ./2025-01-03_00-55-22.png:
3f1f067adc45e49128033561018ccb8c9b79c655a65700bc425f1171f9255711
CertUtil: -hashfile command completed successfully.

# OPTIONS: SHA256 to MD5/SHA1/SHA512

Random¶

Simple UFW Bulk Import¶

cat whitelist.txt
198.51.100.55
198.51.100.43
203.0.113.4

# SCRIPT.sh
while read ip; do
  sudo ufw allow in on eth0 from $ip to 192.0.2.0/24 port 80 proto tcp
  sudo ufw allow in on eth0 from $ip to 192.0.2.0/24 port 443 proto tcp
done < whitelist.txt

Later, find notes¶

Firewall logs
get headers for ssh, etc
curl, get redirects