Class: Recog::Nizer

Inherits:
Object
  • Object
show all
Defined in:
lib/recog/nizer.rb

Constant Summary collapse

DEFAULT_OS_CERTAINTY =

Default certainty ratings where none are specified in the fingerprint itself

0.85
DEFAULT_SERVICE_CERTAINTY =

Most frequent weights are 0.9, 1.0, and 0.5

0.85
HOST_ATTRIBUTES =

Non-weighted host attributes that can be extracted from fingerprint matches

%W{
  host.domain
  host.id
  host.ip
  host.mac
  host.name
  host.time
  hw.device
  hw.family
  hw.product
  hw.vendor
}
@@db_manager = 
nil

Class Method Summary collapse

Class Method Details

.best_os_match(matches) ⇒ Object

Consider an array of match outputs, choose the best result, taking into account the granularity of OS vs Version vs SP vs Language. Only consider fields relevant to the host (OS, name, mac address, etc).



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# File 'lib/recog/nizer.rb', line 49

def self.best_os_match(matches)

  # The result hash we return to the caller
  result = {}

  # Certain attributes should be evaluated separately
  host_attrs  = {}

  # Bucket matches into matched OS product names
  os_products = {}

  matches.each do |m|
    # Count how many times each host attribute value is asserted
    (HOST_ATTRIBUTES & m.keys).each do |ha|
      host_attrs[ha]        ||= {}
      host_attrs[ha][m[ha]] ||= 0
      host_attrs[ha][m[ha]]  += 1
    end

    next unless m.has_key?('os.product')

    # Group matches by OS product and normalize certainty
    cm = m.dup
    cm['os.certainty'] = ( m['os.certainty'] || DEFAULT_OS_CERTAINTY ).to_f
    os_products[ cm['os.product'] ] ||= []
    os_products[ cm['os.product'] ]  << cm
  end

  #
  # Select the best host attribute value by highest frequency
  #
  host_attrs.keys.each do |hk|
    ranked_attr = host_attrs[hk].keys.sort do |a,b|
      host_attrs[hk][b] <=> host_attrs[hk][a]
    end
    result[hk] = ranked_attr.first
  end

  # Unable to guess the OS without OS matches
  unless os_products.keys.length > 0
    return result
  end

  #
  # Select the best operating system name by combined certainty of all
  # matches within an os.product group. Multiple weak matches can
  # outweigh a single strong match by design.
  #
  ranked_os = os_products.keys.sort do |a,b|
    os_products[b].map{ |r| r['os.certainty'] }.inject(:+) <=>
    os_products[a].map{ |r| r['os.certainty'] }.inject(:+)
  end

  # Within the best match group, try to fill in missing attributes
  os_name = ranked_os.first

  # Find the best match within the winning group
  ranked_os_matches = os_products[os_name].sort do |a,b|
    b['os.certainty'] <=> a['os.certainty']
  end

  # Fill in missing result values in descending order of best match
  ranked_os_matches.each do |rm|
    rm.each_pair do |k,v|
      result[k] ||= v
    end
  end

  result
end

.best_service_match(matches) ⇒ Object

Consider an array of match outputs, choose the best result, taking into account the granularity of service. Only consider fields relevant to the service.



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# File 'lib/recog/nizer.rb', line 125

def self.best_service_match(matches)

  # The result hash we return to the caller
  result = {}

  # Bucket matches into matched service product names
  service_products = {}

  matches.select{ |m| m.has_key?('service.product') }.each do |m|
    # Group matches by product and normalize certainty
    cm = m.dup
    cm['service.certainty'] = ( m['service.certainty'] || DEFAULT_SERVICE_CERTAINTY ).to_f
    service_products[ cm['service.product'] ] ||= []
    service_products[ cm['service.product'] ]  << cm
  end

  # Unable to guess the service without service matches
  unless service_products.keys.length > 0
    return result
  end

  #
  # Select the best service name by combined certainty of all matches
  # within an service.product group. Multiple weak matches can
  # outweigh a single strong match by design.
  #
  ranked_service = service_products.keys.sort do |a,b|
    service_products[b].map{ |r| r['service.certainty'] }.inject(:+) <=>
    service_products[a].map{ |r| r['service.certainty'] }.inject(:+)
  end

  # Within the best match group, try to fill in missing attributes
  service_name = ranked_service.first

  # Find the best match within the winning group
  ranked_service_matches = service_products[service_name].sort do |a,b|
    b['service.certainty'] <=> a['service.certainty']
  end

  # Fill in missing service values in descending order of best match
  ranked_service_matches.each do |rm|
    rm.keys.select{ |k| k.index('service.') == 0 }.each do |k|
      result[k] ||= rm[k]
    end
  end

  result
end

.match(match_key, match_string) ⇒ Hash?

Locate a database that corresponds with the match_key and attempt to find a matching fingerprint, stopping at the first hit. Returns nil when no matching database or fingerprint is found.

Parameters:

  • match_key (String) —

    Fingerprint DB name, e.g. 'smb.native_os'

Returns:

  • (Hash, nil) —

    Keys will be host, service, and os attributes



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# File 'lib/recog/nizer.rb', line 31

def self.match(match_key, match_string)
  match_string = match_string.to_s.unpack("C*").pack("C*")
  @@db_manager ||= Recog::DBManager.new
  @@db_manager.databases.each do |db|
    next unless db.match_key == match_key
    db.fingerprints.each do |fprint|
      m = fprint.match(match_string)
      return m if m
    end
  end
  nil
end