Wikipedia

Nmap

Not to be confused with mmap.

Nmap (Network Mapper) is a network scanner created by Gordon Lyon (also known by his pseudonym Fyodor Vaskovich).[5] Nmap is used to discover hosts and services on a computer network by sending packets and analyzing the responses.[6]

Nmap Security Scanner
Original author(s)Gordon Lyon (Fyodor)
Initial releaseSeptember 1997; 27 years ago (1997-09)
Stable release
7.95[1][2] Edit this on Wikidata / 23 April 2024; 7 months ago (23 April 2024)
Repository
Written inC, C++, Python, Lua
Operating systemCross-platform
Available inEnglish
TypeNetwork security
LicenseNPSL[3] or modified GPLv2[4] or proprietary
Websitenmap.org

Nmap provides a number of features for probing computer networks, including host discovery and service and operating system detection. These features are extensible by scripts that provide more advanced service detection,[7] vulnerability detection,[7] and other features. Nmap can adapt to network conditions including latency and congestion during a scan.

Nmap started as a Linux utility[8] and was ported to other systems including Windows, macOS, and BSD.[9] It is most popular on Linux, followed by Windows.[10]

Features

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Nmap features include:

  • Fast scan (nmap -F [target]) – Performing a basic port scan for fast result.
  • Host discovery – Identifying hosts on a network. For example, listing the hosts that respond to TCP and/or ICMP requests or have a particular port open.
  • Port scanning – Enumerating the open ports on target hosts.
  • Version detection – Interrogating network services on remote devices to determine application name and version number.[11]
  • Ping Scan – Check host by sending ping requests.
  • TCP/IP stack fingerprinting – Determining the operating system and hardware characteristics of network devices based on observations of network activity of said devices.
  • Scriptable interaction with the target – using Nmap Scripting Engine[12] (NSE) and Lua programming language.

Nmap can provide further information on targets, including reverse DNS names, device types, and MAC addresses.[13]

Typical uses of Nmap:

  • Auditing the security of a device or firewall by identifying the network connections which can be made to, or through it.[14]
  • Identifying open ports on a target host in preparation for auditing.[15]
  • Network inventory, network mapping, maintenance and asset management.[16]
  • Auditing the security of a network by identifying new servers.[17]
  • Generating traffic to hosts on a network, response analysis and response time measurement.[18]
  • Finding and exploiting vulnerabilities in a network.[19]
  • DNS queries and subdomain search

User interfaces

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NmapFE, originally written by Kanchan, was Nmap's official GUI for Nmap versions 2.2 to 4.22.[20] For Nmap 4.50 (originally in the 4.22SOC development series) NmapFE was replaced with Zenmap, a new official graphical user interface based on UMIT, developed by Adriano Monteiro Marques.

Web-based interfaces exist that allow either controlling Nmap or analysing Nmap results from a web browser, such as IVRE.[21]

  •  
    Zenmap, showing results for a port scan against Wikipedia
  •  
    NmapFE, showing results for a port scan against Wikipedia
  •  
    XNmap, a Mac OS X GUI

Output

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Four different output formats are offered by Nmap. Everything is saved to a file except the interactive output. Text processing software can be used to modify Nmap output, allowing the user to customize reports.[22]

Interactive
presented and updated real time when a user runs Nmap from the command line. Various options can be entered during the scan to facilitate monitoring.
XML
a format that can be further processed by XML tools. It can be converted into a HTML report using XSLT.
Grepable
output that is tailored to line-oriented processing tools such as grep, sed, or awk.
Normal
the output as seen while running Nmap from the command line, but saved to a file.
Script kiddie
meant to be an amusing way to format the interactive output replacing letters with their visually alike number representations. For example, Interesting ports becomes Int3rest1ng p0rtz. This is known as Leet.

History

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Nmap was first published in September 1997, as an article in Phrack Magazine with source-code included.[23] With help and contributions of the computer security community, development continued. Enhancements included operating system fingerprinting, service fingerprinting,[11] code rewrites (C to C++), additional scan types, protocol support (e.g. IPv6, SCTP[24]) and new programs that complement Nmap's core features.

Major releases include:[20]

Date Version Significance
December 12, 1998; 26 years ago (1998-12-12) Nmap 2.00 Nmap 2.00 is released, including Operating System fingerprinting[25]
April 11, 1999; 25 years ago (1999-04-11) NmapFE A GTK+ front end, is bundled with Nmap[25]
December 7, 2000; 24 years ago (2000-12-07) Windows port[20]
August 28, 2002; 22 years ago (2002-08-28) Rewrite from C to C++[20]
September 16, 2003; 21 years ago (2003-09-16) The first public release to include service version detection[20]
August 31, 2004; 20 years ago (2004-08-31) Nmap 3.70 Core scan engine rewritten for version 3.70. New engine is called ultra_scan[26]
Summer 2005 Nmap selected for participation in Google Summer of Code.[27] Added features included Zenmap, Nmap Scripting Engine (NSE), Ncat, and 2nd-generation OS detection.
December 13, 2007; 17 years ago (2007-12-13) Nmap 4.50 Nmap 4.50, the 10th Anniversary Edition, was released. Included Zenmap, 2nd-generation OS detection, and the Nmap Scripting Engine[28]
March 30, 2009; 15 years ago (2009-03-30) Nmap 4.85BETA5 Emergency release of Nmap 4.85BETA5, leveraging NSE to detect Conficker infections[29]
July 16, 2009; 15 years ago (2009-07-16) Nmap 5.00 Included netcat-replacement Ncat and Ndiff scan comparison tool[30]
January 28, 2011; 13 years ago (2011-01-28) Nmap 5.50 Included Nping packet generation response analysis and response time measurement, including TCP, UDP and ICMP probe modes.[31][32]
May 21, 2012; 12 years ago (2012-05-21) Nmap 6.00 Released with full IPv6 support.[citation needed]
November 9, 2015; 9 years ago (2015-11-09) Nmap 7.00 [33]
December 20, 2016; 7 years ago (2016-12-20) Nmap 7.40
March 20, 2018; 6 years ago (2018-03-20) Nmap 7.70 [34]
August 10, 2019; 5 years ago (2019-08-10) Nmap 7.80 [35]
October 3, 2020; 4 years ago (2020-10-03) Nmap 7.90 [36] The new fingerprints allow better operating system and service/version detection. 3 new NSE scripts, new protocol library and payloads for host discovery, port scanning and version detection. Npcap 1.0.0, the first fully stable version of the Windows raw packet capturing/sending driver.
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Nmap is a tool that can be used to discover services running on Internet connected systems. Like any tool, it could potentially be used for black hat hacking,[37] as a precursor to attempts to gain unauthorized access to computer systems. However, Nmap is also used by security and systems administrators to assess their own networks for vulnerabilities (i.e. white hat hacking).

System administrators can use Nmap to search for unauthorized servers, or for computers that do not conform to security standards.[38]

In 2003 Supreme Court of Finland has ruled that port scanning has amounted to an attempted computer break in, which was illegal under Finnish Penal code at the time:[39]

In its ruling the Supreme Court stated that the defendant had systematically carried out port scanning operations to gather information for the purpose of unauthorised break-in to the bank's computer network. This amounted to an attempted computer break in.[39]

License

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Nmap was originally distributed under the GNU General Public License (GPL).[23] In later releases, Nmap's authors added clarifications and specific interpretations to the license where they felt the GPL was unclear or lacking.[40] For instance, Nmap 3.50 specifically revoked the license of SCO Group to distribute Nmap software because of their views on the SCO-Linux controversies.[41]

Starting with version 7.90, Nmap transitions to a new custom license NPSL, dual-licensing versions 7.90, 7.91, and 7.92 under both old and new licenses.[42] Several Linux distributions consider the new license non-free.[43][44]

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In The Matrix Reloaded, Trinity is seen using Nmap to access a power plant's computer system,[45] allowing Neo to "physically" break into a building. The appearance of Nmap in the film was widely discussed on Internet forums and hailed as an unusually realistic example of hacking.[46]

Nmap and NmapFE were used in The Listening, a 2006 movie about a former NSA officer who defects and mounts a clandestine counter-listening station high in the Italian alps.

Nmap source code can be seen in the movie Battle Royale, as well as brief views of the command line version of Nmap executing in Live Free or Die Hard and Bourne Ultimatum.[45] In 2013, Nmap continued to make appearances in movies including popular sci-fi movie Elysium.

The film Dredd, a film adaptation of the famous Judge Dredd comics, was released in 2012 and also contains multiple Nmap scenes.[45] Nmap is used for network reconnaissance and exploitation of the slum tower network. It is even seen briefly in the movie's trailer.

The command Nmap is widely used in the video game Hacknet, allowing to probe the network ports of a target system to hack it.

In Snowden, Nmap is used in the aptitude test scene about 14 minutes into the movie.

In academia

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Nmap is an integral part of academic activities. It has been used for research involving the TCP/IP protocol suite and networking in general.[47] Besides being a research tool, Nmap has also become a research topic.[48]

Examples

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$ nmap -f -v -A scanme.nmap.org
Starting Nmap 6.47 ( https://nmap.org ) at 2014-12-29 20:02 CET
Nmap scan report for scanme.nmap.org (74.207.244.221)
Host is up (0.16s latency).
Not shown: 997 filtered ports
PORT     STATE SERVICE    VERSION
22/tcp   open  ssh        OpenSSH 5.3p1 Debian 3ubuntu7.1 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
|   1024 8d:60:f1:7c:ca:b7:3d:0a:d6:67:54:9d:69:d9:b9:dd (DSA)
|_  2048 79:f8:09:ac:d4:e2:32:42:10:49:d3:bd:20:82:85:ec (RSA)
80/tcp   open  http       Apache httpd 2.2.14 ((Ubuntu))
|_http-title: Go ahead and ScanMe!
9929/tcp open  nping-echo Nping echo
Warning: OSScan results may be unreliable because we could not find at least 1 open and 1 closed port
Device type: general purpose|phone|storage-misc|WAP
Running (JUST GUESSING): Linux 2.6.X|3.X|2.4.X (94%), Netgear RAIDiator 4.X (86%)
OS CPE: cpe:/o:linux:linux_kernel:2.6.38 cpe:/o:linux:linux_kernel:3 cpe:/o:netgear:raidiator:4 cpe:/o:linux:linux_kernel:2.4
Aggressive OS guesses: Linux 2.6.38 (94%), Linux 3.0 (92%), Linux 2.6.32 - 3.0 (91%), Linux 2.6.18 (91%), Linux 2.6.39 (90%), Linux 2.6.32 - 2.6.39 (90%), Linux 2.6.38 - 3.0 (90%), Linux 2.6.38 - 2.6.39 (89%), Linux 2.6.35 (88%), Linux 2.6.37 (88%)
No exact OS matches for host (test conditions non-ideal).
Network Distance: 13 hops
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

TRACEROUTE (using port 80/tcp)
HOP RTT       ADDRESS
1   14.21 ms  151.217.192.1
2   5.27 ms   ae10-0.mx240-iphh.shitty.network (94.45.224.129)
3   13.16 ms  hmb-s2-rou-1102.DE.eurorings.net (134.222.120.121)
4   6.83 ms   blnb-s1-rou-1041.DE.eurorings.net (134.222.229.78)
5   8.30 ms   blnb-s3-rou-1041.DE.eurorings.net (134.222.229.82)
6   9.42 ms   as6939.bcix.de (193.178.185.34)
7   24.56 ms  10ge10-6.core1.ams1.he.net (184.105.213.229)
8   30.60 ms  100ge9-1.core1.lon2.he.net (72.52.92.213)
9   93.54 ms  100ge1-1.core1.nyc4.he.net (72.52.92.166)
10  181.14 ms 10ge9-6.core1.sjc2.he.net (184.105.213.173)
11  169.54 ms 10ge3-2.core3.fmt2.he.net (184.105.222.13)
12  164.58 ms router4-fmt.linode.com (64.71.132.138)
13  164.32 ms scanme.nmap.org (74.207.244.221)

OS and Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 28.98 seconds

See also

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Bibliography

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  • Fyodor Lyon, Gordon (1 January 2009). Nmap Network Scanning: The Official Nmap Project Guide to Network Discovery and Security Scanning. Insecure.com LLC. p. 468. ISBN 978-0-9799587-1-7.

References

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  1. ^ "Nmap Change Log". 23 April 2024. Retrieved 26 April 2024.
  2. ^ Gordon Lyon (5 May 2024). "Nmap 7.95 released: OS and service detection signatures galore!". Retrieved 5 May 2024.
  3. ^ "Nmap Public Source License". Retrieved 2021-12-15.
  4. ^ "Nmap license". Archived from the original on 2018-07-20. Retrieved 2019-01-21.
  5. ^ "Matrix mixes life and hacking". BBC News. 2003-05-19. Retrieved 2018-10-28.
  6. ^ Joshi, Sagar (2021-02-25). "What is Nmap And Why You Should Use It?". The Hack Report. Retrieved 2021-03-01.
  7. ^ a b "Nmap Scripting Engine: Introduction". Nmap.org. Retrieved 2018-10-28.
  8. ^ "The History and Future of Nmap". Nmap.org. Retrieved 2018-10-28.
  9. ^ "Other Platforms". Nmap.org. Retrieved 2018-10-28.
  10. ^ "Nmap Installation for Windows". Nmap.org. Retrieved 2018-10-28.
  11. ^ a b "Service and Application Version Detection". Nmap.org. Retrieved 2018-10-28.
  12. ^ "Nmap Scripting Engine". Nmap.org. Retrieved 2018-10-28.
  13. ^ "Nmap Reference Guide". Nmap.org. Retrieved 2018-10-28.
  14. ^ Nmap Overview and Demonstration.
  15. ^ When Good Scanners Go Bad, From [1] Archived 2000-06-14 at the Wayback Machine, Computerworld 22 March 1999
  16. ^ "Linux.lat". Google News. Retrieved 2024-07-01.
  17. ^ "nmap-audit – Network auditing with Nmap". heavyk.org. Archived from the original on 2009-04-01. Retrieved 2018-10-28.
  18. ^ "Nping - Network packet generation tool / ping utility". Nmap.org. Retrieved 2018-10-28.
  19. ^ Leyden, John (2014-08-15). "Revealed ... GCHQ's incredible hacking tool to sweep net for vulnerabilities: Nmap". TheRegister.co.uk. Retrieved 2018-10-28.
  20. ^ a b c d e "Nmap Changelog". Nmap.org. Retrieved 2018-10-29.
  21. ^ "IVRE homepage". Retrieved 2018-10-28.
  22. ^ "Nmap Reference Guide: Output". Nmap.org. Retrieved 2018-10-29.
  23. ^ a b "The Art of Port Scanning". Phrack Magazine. Vol. 7, no. 51. 1997-09-01. Retrieved 2018-10-29.
  24. ^ "SCTP Support for Nmap". Roe.ch. 2011-05-10. Retrieved 2018-10-29.
  25. ^ a b "The History and Future of Nmap". Nmap.org. Retrieved 2018-10-29.
  26. ^ "Nmap 3.70 Released—Core Scan Engine Rewrite!". Seclists.org. 2004-08-31. Retrieved 2018-10-29.
  27. ^ "Google sponsors Nmap summer student developers". Seclists.org. 2005-06-02. Retrieved 2018-10-29.
  28. ^ "Nmap 4.50 Press Release". Insecure.org. 2007-12-13. Retrieved 2018-10-29.
  29. ^ "Nmap 4.85BETA5: Now with Conficker detection!". Seclists.org. 2009-03-30. Retrieved 2018-10-29.
  30. ^ "Nmap 5.00 Released". Nmap.org. 2009-07-16. Retrieved 2018-10-29.
  31. ^ "nmap/nping/docs/nping.1 at master · nmap/nmap". GitHub.
  32. ^ "Nmap 5.50: Now with Gopher protocol support!". Seclists.org. 2011-01-28. Retrieved 2018-10-29.
  33. ^ "Nmap 7 Released". Nmap.org. 2015-11-19. Retrieved 2018-10-29.
  34. ^ "Nmap 7.70". Nmap.org. 2018-03-20. Retrieved 2018-10-29.
  35. ^ "Nmap 7.80". Nmap.org. 2019-08-10. Retrieved 2019-08-10.
  36. ^ "Nmap 7.90". Nmap.org. 2019-10-03. Retrieved 2020-10-03.
  37. ^ Poulsen, Kevin (2004-11-24). "Hacking tool reportedly draws FBI subpoenas". SecurityFocus.com. Retrieved 2018-10-29.
  38. ^ "How To Conduct A Security Audit" (PDF). PC Network Advisor. No. 120. July 2000. Archived from the original (PDF) on 2021-04-27. Retrieved 2018-10-29.
  39. ^ a b "First ruling by the Supreme Court of Finland on attempted break-in". Osborne Clarke. 2003. Archived from the original on 2005-05-05. Retrieved 2018-10-29.
  40. ^ "Important Nmap License Terms". Nmap.org. Archived from the original on 2018-07-20. Retrieved 2018-10-29.
  41. ^ "Nmap 3.50 Press Release". 2004-02-20. Retrieved 2018-10-29.
  42. ^ "Nmap Public Source License". Nmap.org. Retrieved 2021-12-15.
  43. ^ "Nmap Public Source License (NPSL) Version 0.92". Fedora Mailing-Lists. Retrieved 2021-12-15.
  44. ^ "Add NPSL (nmap license) to MISC_FREE". Gentoo's Bugzilla. Retrieved 2021-12-15.
  45. ^ a b c "Nmap In The Movies". Retrieved 2018-10-29.
  46. ^ Poulsen, Kevin (2003-05-16). "Matrix Sequel Has Hacker Cred". The Register. Retrieved 2018-10-29.
  47. ^ Haines, J.; Ryder, D.K.; Tinnel, L.; Taylor, S. (2003-02-19). "Validation of sensor alert correlators". IEEE Security & Privacy. 99 (1): 46–56. doi:10.1109/MSECP.2003.1176995.
  48. ^ Medeiros, João Paulo S.; Brito Jr., Agostinho M.; Pires, Paulo S. Motta (2009). "A Data Mining Based Analysis of Nmap Operating System Fingerprint Database". Computational Intelligence in Security for Information Systems. Advances in Intelligent and Soft Computing. Vol. 63. pp. 1–8. doi:10.1007/978-3-642-04091-7_1. ISBN 978-3-642-04090-0.
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