Upgrade Simple Shells to Fully Interactive TTYs

Upgrade to Fully Interactive TTYs #

At a Glance #

More often than not, reverse, or bind shells are shells with limited interactive capabilities. Meaning no job control, no auto-completion, no STDERR output, and, most important, poor signal handling and limited commands support. To fully leverage the shell it is convenient to upgrade to an interactive TTY with extended features.

Note: To check if the shell is a TTY shell use the tty command.

Shell to Bash #

Upgrade from shell to bash.

SHELL=/bin/bash script -q /dev/null

Python PTY Module 1 #

Spawn /bin/bash using Python’s PTY module, and connect the controlling shell with its standard I/O.

python -c 'import pty; pty.spawn("/bin/bash")'

Fully Interactive TTY #

Background the current remote shell (^Z), update the local terminal line settings with stty2 and bring the remote shell back.

stty raw -echo && fg

After bringing the job back the cursor will be pushed to the left. Reinitialize the terminal with reset.

  1. “Pty — Pseudo-Terminal Utilities.” 3.8.3 Documentation, https://docs.python.org/3/library/pty.html↩︎

  2. “Stty.” Linux Manual Page, https://man7.org/linux/man-pages/man1/stty.1.html↩︎