OverTheWire is a set of wargames that teach various security concepts. I’ve collected a few notes from each of the games I’ve completed here.


file guesses file types based on the content of the file:

$ file test.py 
test.py: Python script text executable, ASCII text
$ file ./cProgram
cProgram: Mach-O 64-bit executable x86_64

find can take -user, -group, and -size flags.

tr can rot13 if you can remember that M is the 13th letter of the alphabet: tr A-Za-z N-ZA-Mn-za-m.

nmap has lots of options, but usually I just want to scan a range of ports: nmap -p 31000-32000 example.com.

nc is great for passing things around in an open network. nc -l 1234 to listen, nc example.com 1234 to connect.

openssl can open a TLS connection: openssl s_client -connect example.com:443.


ltrace shows the library calls made by a program.

dtrace and strace are for system calls.

gdb with TUI is good too.


Check common locations like robots.txt and try going up one level from known URLs.

mitmproxy is great for browsing while transparently modifying headers (e.g. re-writing the Referer header to make it appear as though every page you visit on a website is the first page you are visiting).

Sanitize your input. Better, use a library to sanitize it for your specific case (e.g. to use in a SQL query).