Add documentation to 'plymouth' splash screen

_gtfobins/plymouth.md

@@ -0,0 +1,24 @@
+---
+description: |
+    Plymouth is a bootsplash screen providing flicker free boot splash animations with native resolution. Plymouth works with
+    a daemon (`plymouthd`) running in the background displaying the actual graphic to the TTY and the `plymouth` command is
+    used to interact with the daemon. The `plymouth` command can be used to request the daemon to act, such as display splash
+    screen, request user input or similar.
+functions:
+  sudo:
+    - description: |
+        To achieve code execution, it is required that `plymouthd` is already running as root or can be started as root (with sudo 
+        or equivalent). It is also required to have tty access to input characters such as keyboard access to the machine. It is 
+        usually best to save the following code snipet to a script (e.g. `priv-esc.sh`) and execute that as the first command
+        will take over the TTY and you will loose terminal access (if executed from the same TTY) until `hide-splash`.
+
+        `show-splash` is used to take control over the TTY and display the splash screen. `pause-progress` is used to prevent
+        plymouth from automatically quiting in some cases as we are already booted. `ask-for-password` will ask the user for a
+        text password (usually to decrypt a LUKS disk encryption). We can tell plymouth to send this input to any program, such
+        as `/bin/sh` to execute whatever input we gave. Then run `hide-splash` to hide the splash screen and return to normal.
+    code: |
+        sudo plymouth show-splash
+        sudo plymouth pause-progress
+        sudo plymouth ask-for-password --prompt='Execute root command:' --command=/bin/sh
+        sudo plymouth hide-splash
+---