Issues with Upgrading and Stabilizing Reverse Shell in Fish Shell about fish-shell

[zanchey]

Did you write this using ChatGPT or another LLM? It does not make sense.

[faho]

Use python3 -c 'import pty;pty.spawn("/bin/bash")' to upgrade and stabilize the reverse shell.

This starts a bash. At that point, fish is entirely out of the picture.

However, if you do run "/usr/bin/fish" instead, you will find that it started something that isn't really a fully usable terminal - e.g. fish will fail to get the correct dimensions for the terminal. It needs that in order to be able to move the cursor properly, which is necessary for highlighting, suggestions, the completion pager, ...

A lot of its drawing will also fail, and the input doesn't work as expected.

Fish demands a lot more from the terminal than bash, and will e.g. set the terminal modes like it needs.

It appears that fish simply won't run properly in whatever is presenting the terminal here (rlwrap or python's pty module).

I'm going to say that we simply do not target this usecase. Sorry.

[uhtred-X]

Did you write this using ChatGPT or another LLM? It does not make sense.
It will only make sense if you have conducted some penetration testing or engaged in CTF-like activities and stabilized your shell after spawning it. Also sorry yes I used ChatGPT because my english isn't that good so I wrote a raw query then ask chatgpt for correction in sentences but issue is very understandable if you know the concept I'm talking about.

[uhtred-X]

Use python3 -c 'import pty;pty.spawn("/bin/bash")' to upgrade and stabilize the reverse shell.

This starts a bash. At that point, fish is entirely out of the picture.

However, if you do run "/usr/bin/fish" instead, you will find that it started something that isn't really a fully usable terminal - e.g. fish will fail to get the correct dimensions for the terminal. It needs that in order to be able to move the cursor properly, which is necessary for highlighting, suggestions, the completion pager, ...

A lot of its drawing will also fail, and the input doesn't work as expected.

Fish demands a lot more from the terminal than bash, and will e.g. set the terminal modes like it needs.

It appears that fish simply won't run properly in whatever is presenting the terminal here (rlwrap or python's pty module).

I'm going to say that we simply do not target this usecase. Sorry.

fish is not typically included as a default package/binary in systems so I can't spawn a shell in fish if it is not present there, so ideal choices left are /bin/sh and /bin/bash. I'm using fish as my terminal where I'm running the netcat listener. I don't have much idea how the environment variables and other things work when we spawn a shell and the try to make it more interactive using stty but in bash shell it work fine so there must be some solution for fish as well. I guess you are not getting the actual picture of the issue and fault is mine I'm not that good to display it. Would you be open to examining the issue further if I provide a video demonstration in both bash and fish as my terminal?

[uhtred-X]

Use python3 -c 'import pty;pty.spawn("/bin/bash")' to upgrade and stabilize the reverse shell.

This starts a bash. At that point, fish is entirely out of the picture.

However, if you do run "/usr/bin/fish" instead, you will find that it started something that isn't really a fully usable terminal - e.g. fish will fail to get the correct dimensions for the terminal. It needs that in order to be able to move the cursor properly, which is necessary for highlighting, suggestions, the completion pager, ...

A lot of its drawing will also fail, and the input doesn't work as expected.

Fish demands a lot more from the terminal than bash, and will e.g. set the terminal modes like it needs.

It appears that fish simply won't run properly in whatever is presenting the terminal here (rlwrap or python's pty module).

I'm going to say that we simply do not target this usecase. Sorry.

I guess, I have to temporarily switch to zsh or any other shell for such tasks but I love to use fish as my default shell, it has many much features than others. BTW thanks for your time and your response.