Class: SSHScan::SshFp

Inherits:
Object
  • Object
show all
Defined in:
lib/ssh_scan/ssh_fp.rb

Constant Summary collapse

ALGO_MAP = 
{
  0 => "reserved", # Reference: https://tools.ietf.org/html/rfc4255#section-2.4
  1 => "rsa",      # Reference: https://tools.ietf.org/html/rfc4255#section-2.4
  2 => "dss",      # Reference: https://tools.ietf.org/html/rfc4255#section-2.4
  3 => "ecdsa",    # Reference: https://tools.ietf.org/html/rfc6594#section-5.3.1
  4 => "ed25519"   # Reference: https://tools.ietf.org/html/rfc7479
}
FPTYPE_MAP = 
{
  0 => "reserved",  # Reference: https://tools.ietf.org/html/rfc4255#section-2.4
  1 => "sha1",      # Reference: https://tools.ietf.org/html/rfc4255#section-2.4
  2 => "sha256"     # Reference: https://tools.ietf.org/html/rfc6594#section-5.1.2
}

Instance Method Summary collapse

Instance Method Details

#query(fqdn) ⇒ Object 



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# File 'lib/ssh_scan/ssh_fp.rb', line 22

def query(fqdn)
  sshfp_records = []

  # try up to 5 times to resolve ssh_fp's
  5.times do

    # Reference: https://stackoverflow.com/questions/28867626/how-to-use-resolvdnsresourcegeneric
    # Note: this includes some fixes too, I'll post a direct link back to the SO article.
    Resolv::DNS.open do |dns|
       all_records = dns.getresources(fqdn, Resolv::DNS::Resource::IN::ANY ) rescue nil
       all_records.each do |rr|
          if rr.is_a? Resolv::DNS::Resource::Generic then
             classname = rr.class.name.split('::').last
             if classname == "Type44_Class1"
               data = rr.data.bytes
               algo = data[0].to_s
               fptype = data[1].to_s
               fp = data[2..-1]
               hex = fp.map{|b| b.to_s(16).rjust(2,'0') }.join(':')
               sshfp_records << {"fptype" => FPTYPE_MAP[fptype.to_i], "algo" => ALGO_MAP[algo.to_i], "hex" => hex}
             end
          end
       end
    end

    if sshfp_records.any?
      return sshfp_records.sort_by { |k| k["hex"] }
    end

    sleep 0.5
  end 

  return sshfp_records
end