Good tradecraft keeps espionage routine and boring.
—Vejas Gabriel Liulevicius
A collection of useful websites, browser addons, and commands that will likely be useful along the way.
http://rumkin.com/tools/cipher/
https://retdec.com/decompilation/
https://www.ssllabs.com/ssltest/analyze.html
https://searchdns.netcraft.com/
https://hashkiller.co.uk/ntlm-decrypter.aspx
https://www.onlinedisassembler.com/odaweb/
http://www.csgnetwork.com/hexaddsubcalc.html
https://gchq.github.io/CyberChef/
https://www.cleancss.com/html-beautify/
FoxyProxy
HackBar
TamperData
Kali> exiftool filename.png
Kali> steghide extract -sf filename.png