TCP SYN Port Scanner - Metasploit


This page contains detailed information about how to use the auxiliary/scanner/portscan/syn metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.

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Module Overview

Name: TCP SYN Port Scanner
Module: auxiliary/scanner/portscan/syn
Source code: modules/auxiliary/scanner/portscan/syn.rb
Disclosure date: -
Last modification time: 2017-07-24 06:26:21 +0000
Supported architecture(s): -
Supported platform(s): -
Target service / protocol: -
Target network port(s): -
List of CVEs: -

Enumerate open TCP services using a raw SYN scan.

Module Ranking and Traits

Module Ranking:

  • normal: The exploit is otherwise reliable, but depends on a specific version and can't (or doesn't) reliably autodetect. More information about ranking can be found here.

Basic Usage

This module is a scanner module, and is capable of testing against multiple hosts.

msf > use auxiliary/scanner/portscan/syn
msf auxiliary(syn) > show options
    ... show and set options ...
msf auxiliary(syn) > set RHOSTS ip-range
msf auxiliary(syn) > exploit

Other examples of setting the RHOSTS option:

Example 1:

msf auxiliary(syn) > set RHOSTS 192.168.1.3-192.168.1.200

Example 2:

msf auxiliary(syn) > set RHOSTS 192.168.1.1/24

Example 3:

msf auxiliary(syn) > set RHOSTS file:/tmp/ip_list.txt

Required Options

  • RHOSTS: The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'

Knowledge Base

Description

This module will attempt to initiate a TCP/IP connection with ports on the victim machine. It is this done by sending a SYN packet, and if victim replies with a SYN/ACK packet that means the port is open. Then the attacker sends a RST packet, and as a result the victim's machine assumes that there is a communication error. The attacker now knows the state of port without a full tcp connection. Major benefit of TCP SYN scan is that most logging applications do not log the TCP/RST by default.

Options

PORTS

This is the list of TCP ports to test on each host. Formats like 1-3, 1,2,3, 1,2-3, etc. are all supported. Default options is to scan 1-10000 ports.

TIMEOUT

Maximum time to wait for a response. The default value is 500 milliseconds.

VERBOSE

Gives detailed message about the scan of all the ports. It also shows the ports that were closed.

Verification Steps

  1. Do: use auxiliary/scanner/portscan/syn
  2. Do: set RHOSTS [IP]
  3. Do: set PORTS [PORTS]
  4. Do: run
  5. If any of the TCP ports were open they will be discovered, status will be printed indicating as such.

Scenarios

Metaspliotable 2

msf > use auxiliary/scanner/portscan/syn
msf auxiliary(syn) > set RHOSTS 192.168.45.159
RHOSTS => 192.168.45.159
msf auxiliary(syn) > set PORTS 1-10000
PORTS => 1-10000
msf auxiliary(syn) > run
[*]  TCP OPEN 192.168.45.159:22
[*]  TCP OPEN 192.168.45.159:23
[*]  TCP OPEN 192.168.45.159:111
[*]  TCP OPEN 192.168.45.159:445
[*]  TCP OPEN 192.168.45.159:512
[*]  TCP OPEN 192.168.45.159:513
[*]  TCP OPEN 192.168.45.159:1099
[*]  TCP OPEN 192.168.45.159:2121
[*]  TCP OPEN 192.168.45.159:3306
[*]  TCP OPEN 192.168.45.159:3632
[*]  TCP OPEN 192.168.45.159:6000
[*]  TCP OPEN 192.168.45.159:6697
[*]  TCP OPEN 192.168.45.159:8009
[*] Scanned 1 of 1 hosts (100% complete)
[*] Auxiliary module execution completed

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Msfconsole Usage

Here is how the scanner/portscan/syn auxiliary module looks in the msfconsole:

msf6 > use auxiliary/scanner/portscan/syn

msf6 auxiliary(scanner/portscan/syn) > show info

       Name: TCP SYN Port Scanner
     Module: auxiliary/scanner/portscan/syn
    License: Metasploit Framework License (BSD)
       Rank: Normal

Provided by:
  kris katterjohn <[email protected]>

Check supported:
  No

Basic options:
  Name       Current Setting  Required  Description
  ----       ---------------  --------  -----------
  BATCHSIZE  256              yes       The number of hosts to scan per set
  DELAY      0                yes       The delay between connections, per thread, in milliseconds
  INTERFACE                   no        The name of the interface
  JITTER     0                yes       The delay jitter factor (maximum value by which to +/- DELAY) in milliseconds.
  PORTS      1-10000          yes       Ports to scan (e.g. 22-25,80,110-900)
  RHOSTS                      yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
  SNAPLEN    65535            yes       The number of bytes to capture
  THREADS    1                yes       The number of concurrent threads (max one per host)
  TIMEOUT    500              yes       The reply read timeout in milliseconds

Description:
  Enumerate open TCP services using a raw SYN scan.

Module Options

This is a complete list of options available in the scanner/portscan/syn auxiliary module:

msf6 auxiliary(scanner/portscan/syn) > show options

Module options (auxiliary/scanner/portscan/syn):

   Name       Current Setting  Required  Description
   ----       ---------------  --------  -----------
   BATCHSIZE  256              yes       The number of hosts to scan per set
   DELAY      0                yes       The delay between connections, per thread, in milliseconds
   INTERFACE                   no        The name of the interface
   JITTER     0                yes       The delay jitter factor (maximum value by which to +/- DELAY) in milliseconds.
   PORTS      1-10000          yes       Ports to scan (e.g. 22-25,80,110-900)
   RHOSTS                      yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
   SNAPLEN    65535            yes       The number of bytes to capture
   THREADS    1                yes       The number of concurrent threads (max one per host)
   TIMEOUT    500              yes       The reply read timeout in milliseconds

Advanced Options

Here is a complete list of advanced options supported by the scanner/portscan/syn auxiliary module:

msf6 auxiliary(scanner/portscan/syn) > show advanced

Module advanced options (auxiliary/scanner/portscan/syn):

   Name                 Current Setting  Required  Description
   ----                 ---------------  --------  -----------
   GATEWAY_PROBE_HOST   8.8.8.8          yes       Send a TTL=1 random UDP datagram to this host to discover the default gateway's MAC
   GATEWAY_PROBE_PORT                    no        The port on GATEWAY_PROBE_HOST to send a random UDP probe to (random if 0 or unset)
   SECRET               1297303073       yes       A 32-bit cookie for probe requests.
   ShowProgress         true             yes       Display progress messages during a scan
   ShowProgressPercent  10               yes       The interval in percent that progress should be shown
   VERBOSE              false            no        Enable detailed status messages
   WORKSPACE                             no        Specify the workspace for this module

Auxiliary Actions

This is a list of all auxiliary actions that the scanner/portscan/syn module can do:

msf6 auxiliary(scanner/portscan/syn) > show actions

Auxiliary actions:

   Name  Description
   ----  -----------

Evasion Options

Here is the full list of possible evasion options supported by the scanner/portscan/syn auxiliary module in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):

msf6 auxiliary(scanner/portscan/syn) > show evasion

Module evasion options:

   Name  Current Setting  Required  Description
   ----  ---------------  --------  -----------

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Error Messages

This module may fail with the following error messages:

Error Messages

Check for the possible causes from the code snippets below found in the module source code. This can often times help in identifying the root cause of the problem.

PORTS

Here is a relevant code snippet related to the "PORTS" error message:

40:	  end
41:	
42:	  def run_batch(hosts)
43:	    ports = Rex::Socket.portspec_crack(datastore['PORTS'])
44:	    if ports.empty?
45:	      raise Msf::OptionValidateError.new(['PORTS'])
46:	    end
47:	
48:	    jitter_value = datastore['JITTER'].to_i
49:	    if jitter_value < 0
50:	      raise Msf::OptionValidateError.new(['JITTER'])

JITTER

Here is a relevant code snippet related to the "JITTER" error message:

45:	      raise Msf::OptionValidateError.new(['PORTS'])
46:	    end
47:	
48:	    jitter_value = datastore['JITTER'].to_i
49:	    if jitter_value < 0
50:	      raise Msf::OptionValidateError.new(['JITTER'])
51:	    end
52:	
53:	    delay_value = datastore['DELAY'].to_i
54:	    if delay_value < 0
55:	      raise Msf::OptionValidateError.new(['DELAY'])

DELAY

Here is a relevant code snippet related to the "DELAY" error message:

50:	      raise Msf::OptionValidateError.new(['JITTER'])
51:	    end
52:	
53:	    delay_value = datastore['DELAY'].to_i
54:	    if delay_value < 0
55:	      raise Msf::OptionValidateError.new(['DELAY'])
56:	    end
57:	
58:	    open_pcap
59:	    pcap = self.capture
60:

Error

Here is a relevant code snippet related to the "Error" error message:

87:	          if (reply.is_tcp? and reply.tcp_flags.syn == 1 and reply.tcp_flags.ack == 1)
88:	            print_good(" TCP OPEN #{dhost}:#{dport}")
89:	            report_service(:host => dhost, :port => dport)
90:	          end
91:	        rescue ::Exception
92:	          print_error("Error: #{$!.class} #{$!}")
93:	        end
94:	      end
95:	    end
96:	
97:	    close_pcap

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See Also

Check also the following modules related to this module:

Authors

kris katterjohn

Version

This page has been produced using Metasploit Framework version 6.2.26-dev. For more modules, visit the Metasploit Module Library.

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