SSHDUMP(1) | SSHDUMP(1) |
NAME¶
sshdump - Provide interfaces to capture from a remote host through SSH using a remote capture binary.
SYNOPSIS¶
sshdump [ --help ] [ --version ] [ --extcap-interfaces ] [ --extcap-dlts ] [ --extcap-interface=<interface> ] [ --extcap-config ] [ --extcap-capture-filter=<capture filter> ] [ --capture ] [ --fifo=<path to file or pipe> ] [ --remote-host=<IP address> ] [ --remote-port=<TCP port> ] [ --remote-username=<username> ] [ --remote-password=<password> ] [ --sshkey=<private key path> ] [ --sshkey-passphrase=<private key passphrase> ] [ --proxycommand=<SSH proxy command> ] [ --remote-interface=<interface> ] [ --remote-capture-command-select=<capture command selection> ] [ --remote-capture-command=<capture command> ] [ --remote-priv=<privilege elevation command selection> ] [ --remote-priv-user=<privileged user name> ] [ --remote-noprom ] [ --remote-filter=<remote capture filter> ] [ --remote-count=<number> ]
sshdump --extcap-interfaces
sshdump --extcap-interface=<interface> --extcap-dlts
sshdump --extcap-interface=<interface> --extcap-config
sshdump --extcap-interface=<interface> --fifo=<path to file or pipe> --capture --remote-host=myremotehost --remote-port=22 --remote-username=user --remote-interface=eth2 --remote-capture-command='tcpdump -U -i eth0 -w-'
DESCRIPTION¶
Sshdump is an extcap tool that allows one to run a remote capture tool over a SSH connection. The requirement is that the capture executable must have the capabilities to capture from the wanted interface.
The feature is functionally equivalent to run commands like
$ ssh remoteuser@remotehost -p 22222 'tcpdump -U -i IFACE -w -' > FILE & $ wireshark FILE
$ ssh remoteuser@remotehost '/sbin/dumpcap -i IFACE -P -w - -f "not port 22"' > FILE & $ wireshark FILE
$ ssh somehost dumpcap -P -w - -f udp | tshark -i -
Typically sshdump is not invoked directly. Instead it can be configured through the Wireshark graphical user interface or its command line. The following will start Wireshark and start capturing from host remotehost:
$ wireshark '-oextcap.sshdump.remotehost:"remotehost"' -i sshdump -k
To explicitly control the remote capture command:
$ wireshark '-oextcap.sshdump.remotehost:"remotehost"' \
'-oextcap.sshdump.remotecapturecommand:"tcpdump -i eth0 -Uw- not port 22"' \
-i sshdump -k
Supported interfaces:
OPTIONS¶
--help
--version
--extcap-interfaces
--extcap-interface=<interface>
--extcap-dlts
--extcap-config
--extcap-capture-filter=<capture filter>
--capture
--fifo=<path to file or pipe>
--remote-host=<remote host>
--remote-port=<remote port>
--remote-username=<username>
--remote-password=<password>
--sshkey=<SSH private key path>
--sshkey-passphrase=<SSH private key passphrase>
--proxycommand=<proxy command>
--remote-interface=<remote interface>
--remote-capture-command-select=<capture command-selection>
The selection of the build-in support for remote capture commands. Either dumpcap for a remote capture command using dumpcap, tcpdump for a remote capture command using tcpdump, or other, where the remote capture command is to be given with the --remote-capture-command option.
Note that selecting dumpcap allows for specifying multiple capture interfaces as a whitespace separated list, while tcpdump does not.
--remote-capture-command=<capture command>
A custom remote capture command that produces the remote stream that is shown in Wireshark. The command must be able to produce a PCAP stream written to STDOUT. See below for more examples.
If using tcpdump, use the -w- option to ensure that packets are written to standard output (stdout). Include the -U option to write packets as soon as they are received.
When specified, this command will be used as is, options such as the capture filter (--extcap-capture-filter) will not be appended.
--remote-priv=<privilege elevation command selection>
--remote-priv-user=<privileged user name>
--remote-filter=<capture filter>
--remote-count=<number>
EXAMPLES¶
To see program arguments:
sshdump --help
To see program version:
sshdump --version
To see interfaces:
sshdump --extcap-interfaces
Only one interface (sshdump) is supported.
Example output
interface {value=sshdump}{display=SSH remote capture}
To see interface DLTs:
sshdump --extcap-interface=sshdump --extcap-dlts
Example output
dlt {number=147}{name=sshdump}{display=Remote capture dependent DLT}
To see interface configuration options:
sshdump --extcap-interface=sshdump --extcap-config
Example output
arg {number=0}{call=--remote-host}{display=Remote SSH server address}{type=string}
{tooltip=The remote SSH host. It can be both an IP address or a hostname}{required=true}{group=Server} arg {number=1}{call=--remote-port}{display=Remote SSH server port}{type=unsigned}{default=22}
{tooltip=The remote SSH host port (1-65535)}{range=1,65535}{group=Server} arg {number=2}{call=--remote-username}{display=Remote SSH server username}{type=string}
{tooltip=The remote SSH username. If not provided, the current user will be used}{group=Authentication} arg {number=3}{call=--remote-password}{display=Remote SSH server password}{type=password}
{tooltip=The SSH password, used when other methods (SSH agent or key files) are unavailable.}{group=Authentication} arg {number=4}{call=--sshkey}{display=Path to SSH private key}{type=fileselect}
{tooltip=The path on the local filesystem of the private SSH key (OpenSSH format)}{mustexist=true}{group=Authentication} arg {number=5}{call=--sshkey-passphrase}{display=SSH key passphrase}{type=password}
{tooltip=Passphrase to unlock the SSH private key}{group=Authentication} arg {number=6}{call=--proxycommand}{display=ProxyCommand}{type=string}
{tooltip=The command to use as proxy for the SSH connection}{group=Authentication} arg {number=7}{call=--remote-interface}{display=Remote interface}{type=string}
{tooltip=The remote network interface used for capture}{group=Capture} arg {number=8}{call=--remote-capture-command-select}{display=Remote capture command selection}{type=radio}
{tooltip=The remote capture command to build a command line for}{group=Capture}
value {arg=8}{value=dumpcap}{display=dumpcap}
value {arg=8}{value=tcpdump}{display=tcpdump}{default=true}
value {arg=8}{value=other}{display=Other:} arg {number=9}{call=--remote-capture-command}{display=Remote capture command}{type=string}
{tooltip=The remote command used to capture}{group=Capture} arg {number=10}{call=--remote-priv}{display=Gain capture privilege on the remote machine}{type=radio}
{tooltip=Optionally prepend the capture command with sudo or doas on the remote machine}{group=Capture}
value {arg=10}{value=none}{display=none}{default=true}
value {arg=10}{value=sudo}{display=sudo}
value {arg=10}{value=doas -n}{display=doas} arg {number=11}{call=--remote-priv-user}{display=Privileged user name for sudo or doas}{type=string}
{tooltip=User name of privileged user to execute the capture command on the remote machine}{group=Capture} arg {number=12}{call=--remote-noprom}{display=No promiscuous mode}{type=boolflag}
{tooltip=Don't use promiscuous mode on the remote machine}{group=Capture} arg {number=13}{call=--remote-filter}{display=Remote capture filter}{type=string}
{tooltip=The remote capture filter}{default=not ((host myhost) and port 22)}{group=Capture} arg {number=14}{call=--remote-count}{display=Packets to capture}{type=unsigned}{default=0}
{tooltip=The number of remote packets to capture. (Default: inf)}{group=Capture} arg {number=15}{call=--log-level}{display=Set the log level}{type=selector}
{tooltip=Set the log level}{required=false}{group=Debug}
value {arg=14}{value=message}{display=Message}{default=true}
value {arg=14}{value=info}{display=Info}
value {arg=14}{value=debug}{display=Debug}
value {arg=14}{value=noisy}{display=Noisy} arg {number=16}{call=--log-file}{display=Use a file for logging}{type=fileselect}
{tooltip=Set a file where log messages are written}{required=false}{group=Debug}
To capture:
sshdump --extcap-interface=sshdump --fifo=/tmp/ssh.pcap --capture --remote-host 192.168.1.10 --remote-username user --remote-filter "not port 22"
To use different capture binaries:
sshdump --extcap-interface=sshdump --fifo=/tmp/ssh.pcap --capture --remote-host 192.168.1.10 --remote-username user --remote-priv sudo --remote-capture-command-select tcpdump --remote-interface eth0 --remote-noprom
sshdump --extcap-interface=sshdump --fifo=/tmp/ssh.pcap --capture --remote-host 192.168.1.10 --remote-capture-command='dumpcap -i eth0 -P -w -'
sshdump --extcap-interface=sshdump --fifo=/tmp/ssh.pcap --capture --remote-host 192.168.1.10 --remote-capture-command='sudo tcpdump -i eth0 -U -w -'
Note
To stop capturing CTRL+C/kill/terminate the application.
The sshdump binary can be renamed to support multiple instances. For instance if we want sshdump to show up twice in wireshark (for instance to handle multiple profiles), we can copy sshdump to sshdump-host1 and sshdump-host2. Each binary will show up an interface name same as the executable name. Those executables not being "sshdump" will show up as "custom version" in the interface description.
SEE ALSO¶
NOTES¶
Sshdump is part of the Wireshark distribution. The latest version of Wireshark can be found at <https://www.wireshark.org>.
HTML versions of the Wireshark project man pages are available at <https://www.wireshark.org/docs/man-pages>.
AUTHORS¶
Original Author
Dario Lombardo <lomato[AT]gmail.com>
2024-10-10 |