Added My Friend John - Miscellaneous

Miscellaneous/My Friend John/README.md

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+## My Friend John
+The main idea is learning how to use tools for cracking password protected zip files.
+
+#### Step-1:
+We can open [`MyFriendJohn.zip`](./MyFriendJohn.zip) using [7zip](https://www.7-zip.org/) and extract `use-rockyou.zip`.
+
+#### Step-2:
+Now we need a password to open `use-rockyou.zip`. There's a really popular wordlist called rockyou which can be downloaded [here](https://github.com/brannondorsey/naive-hashcat/releases/download/data/rockyou.txt).
+
+#### Step-3:
+We can use [fcrackzip](https://github.com/hyc/fcrackzip)'s dictionary attack: `fcrackzip -v -u -D -p rockyou.txt use-rockyou.zip` using rockyou.
+
+#### Step-4:
+We now see `custom-list.txt` and `custom-list.zip`. We can use the custom word list to unlock the the zip file: `fcrackzip -v -u -D -p custom-list.txt custom-list.zip`.
+
+#### Step-5:
+The last zip file is called `brute-force-pin.zip`. A pin is usually between 4 and 6 numeric digits. `fcrackzip -b -c "1" -l 4-6 -v -u brute-force-pin.zip`. The `-c "1"` means only use numeric digits when bruteforcing.
+
+#### Step-6:
+Finally we get a `flag.txt` and the flag becomes:
+`CTFlearn{s0_n0W_y0uv3_M3t_J0hN}`