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XML Output (`-oX`)
| Chapter 13. Nmap Output Formats |
## XML Output (`-oX`) XML, the extensible markup language, has its share of critics as well as plenty of zealous proponents. I was long in the former group, and only grudgingly incorporated XML into Nmap after volunteers performed most of the work. Since then, I have learned to appreciate the power and flexibility that XML offers, and even wrote this book in the DocBook XML format. I strongly recommend that programmers interact with Nmap through the XML interface rather than trying to parse the normal, interactive, or grepable output. That format includes more information than the others and is extensible enough that new features can be added without breaking existing programs that use it. It can be parsed by standard XML parsers, which are available for all popular programming languages, usually for free. Editors, validators, transformation systems, and many other applications already know how to handle the format. Normal and interactive output, on the other hand, are custom to Nmap and subject to regular changes as I strive for a clearer presentation to end users. Grepable output is also Nmap-specific and tougher to extend than XML. It is considered deprecated, and many Nmap features such as MAC address detection are not presented in this output format. An example of Nmap XML output is shown in Example 13.9, “An example of Nmap XML output” Whitespace has been adjusted for readability. In this case, XML was sent to stdout thanks to the `-oX -` construct. Some programs executing Nmap opt to read the output that way, while others specify that output be sent to a filename and then they read that file after Nmap completes. Example 13.9. An example of Nmap XML output
    # nmap -T4 -A -oX - -p1-1024 scanme.nmap.org
    <?xml version="1.0" ?>
    <!-- nmap 3.78 scan initiated Fri Dec 10 21:40:13 2004 as:
         nmap -T4 -A -oX - -p1-1024 scanme.nmap.org -->
    <nmaprun scanner="nmap" args="nmap -T4 -A -oX - -p1-1024 scanme.nmap.org"
             start="1102743613" startstr="Fri Dec 10 21:40:13 2004"
             version="3.78" xmloutputversion="1.01">
     <scaninfo type="syn" protocol="tcp" numservices="1024" services="1-1024" />
     <verbose level="0" /> <debugging level="0" /> <host><status state="up" />
      <address addr="205.217.153.62" addrtype="ipv4" />
      <hostnames><hostname name="scanme.nmap.org" type="PTR" /></hostnames>
      <ports><extraports state="filtered" count="1019" />
       <port protocol="tcp" portid="22"><state state="open" />
         <service name="ssh" product="OpenSSH" version="3.1p1"
                  extrainfo="protocol 1.99" method="probed" conf="10" /> </port>
       <port protocol="tcp" portid="25"><state state="open" />
         <service name="smtp" product="qmail smtpd" method="probed" conf="10" />
       </port>
       <port protocol="tcp" portid="53"><state state="open" />
         <service name="domain" product="ISC BIND" version="9.2.1" method="probed"
                  conf="10" /> </port>
       <port protocol="tcp" portid="80"><state state="open" />
         <service name="http" product="Apache httpd" version="2.0.39" conf="10"
             extrainfo="(Unix) mod_perl/1.99_07-dev" method="probed" /> </port>
       <port protocol="tcp" portid="113"><state state="closed" />
         <service name="auth" method="table" conf="3" /> </port>
      </ports>
      <os>
       <portused state="open" proto="tcp" portid="22" />
       <portused state="closed" proto="tcp" portid="113" />
       <osclass type="general purpose" vendor="Linux" osfamily="Linux"
                osgen="2.4.X" accuracy="100" />
       <osclass type="general purpose" vendor="Linux" osfamily="Linux"
                osgen="2.5.X" accuracy="100" />
       <osmatch name="Linux 2.4.0 - 2.5.20" accuracy="100" />
       <osmatch name="Linux 2.4.18 - 2.4.20" accuracy="100" />
      </os>
      <uptime seconds="813079" lastboot="Fri Nov 12 15:35:00 2004" />
      <tcpsequence index="1972182" difficulty="Good luck!"
                   values="E2E6D835,E32B1CB7,E3203691,E3740715,E36B40C8,E33B1621"/>
      <ipidsequence class="All zeros" values="0,0,0,0,0,0" />
      <tcptssequence class="100HZ"
                     values="4D8A8C7,4D8A8D3,4D8A8DF,4D8A8EB,4D8A8F7,4D8A903" />
     </host>
     <runstats>
      <finished time="1102743614" timestr="Fri Dec 10 21:40:14 2004" />
      <hosts up="1" down="0" total="1" />
      <!-- Nmap run completed at Fri Dec 10 21:40:14 2004;
           1 IP address (1 host up) scanned in 21.142 seconds -->
     </runstats>
    </nmaprun>
Another advantage of XML is that its verbose nature makes it easier to read and understand than other formats. Readers familiar with Nmap in general can likely understand most of the XML output in Example 13.9, “An example of Nmap XML output” without further documentation. The grepable output format, on the other hand, is tough to decipher without its own reference guide. There are a few aspects of the example XML output which may not be self-explanatory. For example, look at the two `port` elements in Example 13.10, “Nmap XML port elements” Example 13.10. Nmap XML port elements
       <port protocol="tcp" portid="22"><state state="open" />
         <service name="ssh" product="OpenSSH" version="3.1p1"
                  extrainfo="protocol 1.99" method="probed" conf="10" />
       </port>
       <port protocol="tcp" portid="113"><state state="closed" />
         <service name="auth" method="table" conf="3" />
       </port>
The port protocol, ID (port number), state, and service name are the same as would be shown in the interactive output port table. The service product, version, and extrainfo come from version detection and are combined together into one field of the interactive output port table. The `method` and `conf` attributes aren't present in any other output types. The method can be `table`, meaning the service name was simply looked up in `nmap-services` based on the port number and protocol, or it can be `probed`, meaning that it was determined through the version detection system. The `conf` attribute measures the confidence Nmap has that the service name is correct. The values range from one (least confident) to ten. Nmap only has a confidence level of three for ports determined by table lookup, while it is highly confident (level 10) that port 22 of Example 13.10, “Nmap XML port elements” is SSH, because Nmap connected to the port and found a server exhibiting the SSH protocol. One other aspect that some users find confusing is that the attributes nmaprun/start and finished/end hold timestamps given in Unix time, the number of seconds January 1, 1970. This is often easier for programs to handle. For the convenience of human readers, versions 3.78 and newer include the equivalent calendar time written out in the attributes nmaprun/startstr and finished/endstr. If anyone finds other portions of the XML output confusing, let me know and I can cover them here. Nmap includes a document type definition (DTD) which allows XML parsers to validate Nmap XML output. While it is primarily intended for programmatic use, it can also help humans interpret Nmap XML output. The DTD defines the legal elements of the format, and often enumerates the attributes and values they can take on. It is reproduced in Appendix A, Nmap XML Output DTD ### Using XML Output The Nmap XML format can be used in many powerful ways, though few users actually take any advantage of it. I believe this is due to inexperience of many users with XML, combined with a lack of practical, solution-oriented documentation on using the Nmap XML format. This chapter provides several practical examples, including the section called “Manipulating XML Output with Perl” the section called “Output to a Database”, and the section called “Creating HTML Reports” A key advantage of XML is that you do not need to write your owner parser as you do for specialized Nmap output types such as grepable and interactive output. Any general XML parser should do. The XML parser that people are most familiar with is the one in your web browser. Both IE and Mozilla/Firefox include capable parsers that can be used to view Nmap XML data. Using them is as simple as typing the XML filename or URL into the address bar. A document tree-view is shown, allowing you to expand and reduce elements as desired. It also provides syntax highlighting to quickly recognize key elements. If you know you'll be reading Nmap output, saving normal or interactive output as well as XML is advisable as most people find them the easiest to read and interpret. But if you only have XML output because you lost or didn't create the other forms, or because you are debugging a program that uses the XML, then reading the XML in a web browser is often preferable to using a text editor. Figure 13.1, “Reading XML in a web browser” shows Firefox rendering a tree view of Nmap XML. TODO: I may need to change this when I insert XSLT stylesheets into Nmap XML output. When that happens, you will get a pretty, rendered view automatically. Will need to change text after the figure then too. Figure 13.1. Reading XML in a web browser Similarly, spreadsheet programs, including Microsoft Excel, are often able to import Nmap XML data directly for viewing. A major problem with browsing Nmap XML logs directly through a web browser or spreadsheet is that the logs are treaded in a generic way, just like any other XML file. The browser doesn't understand the relative importance of elements, nor how to organize the data for a more useful presentation. With the help of a stylesheet specific to Nmap, the logs can be rendered in a much more useful fashion. This is demonstrated in the section called “Creating HTML Reports”
$crIpT kIddI3 0uTPut (`-oS`) |  | Manipulating XML Output with Perl
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