Apr 19, 2017 LAN Manager (LM) includes client computer and server software from Microsoft that allows users to link personal devices together on a single network. Network capabilities include transparent file and print sharing, user security features, and network administration tools. Apr 19, 2017 The LAN Manager hash is relatively weak and prone to attack compared to the cryptographically stronger NTLM hash. Because the LM hash is stored on the local device in the security database, the passwords can be compromised if the security database, Security Accounts Manager (SAM), is attacked. Sep 23, 2016 Network File Manager 10 is a native Universal Windows App giving you control of your files and folders across your network shares. Developed for simplicity and ease of use, just set up your network share locations and start managing!. Cut, copy, and delete files and folders. (1) An earlier network operating system from Microsoft that ran as a server application under OS/2. Supporting DOS, Windows and OS/2 clients, LAN Manager was superseded by Windows NT Server, and parts of LAN Manager were used in Windows NT and 2000. See LAN Server. (2) (Local Area Network manager) See network administrator. Nov 07, 2017 LAN Manager is the ' grandpa of authentication ' in Windows Systems. It was implemented in 1987 and nowadays it is old and deprecated. And yes of course, it can be broken easily. This protocol is still used by Windows-NT based operating systems to store Password Hashes.
Developer | Microsoft, 3Com |
---|---|
OS family | OS/2 |
Working state | Discontinued |
Source model | Closed source |
Initial release | 1987; 32 years ago |
Final release | 2.2a / 1994; 25 years ago |
Marketing target | Local area networking |
Update method | Re-installation |
Package manager | None |
Platforms | x86 |
License | Proprietary |
Preceded by | MS-Net, Xenix-NET, 3+Share |
LAN Manager was a network operating system (NOS) available from multiple vendors and developed by Microsoft in cooperation with 3Com Corporation. It was designed to succeed 3Com's 3+Sharenetwork server software which ran atop a heavily modified version of MS-DOS.
- 1History
History[edit]
LAN Manager was based on the OS/2 operating system co-developed by IBM and Microsoft. It originally used the Server Message Block protocol atop either the NetBIOS Frames protocol (NBF) or a specialized version of the Xerox Network Systems (XNS) protocol. These legacy protocols had been inherited from previous products such as MS-Net for MS-DOS, Xenix-NET for MS-Xenix, and the afore-mentioned 3+Share. A version of LAN Manager for Unix-based systems called LAN Manager/X was also available.
In 1990, Microsoft announced LAN Manager 2.0 with a host of improvements, including support for TCP/IP as a transport protocol. The last version LAN Manager, 2.2, which included an MS-OS/2 1.31 base operating system, remained Microsoft's strategic server system until the release of Windows NT Advanced Server in 1993.
Versions[edit]
- 1987 – MS LAN Manager 1.0 (Basic/Enhanced)
- 1989 – MS LAN Manager 1.1
- 1991 – MS LAN Manager 2.0
- 1992 – MS LAN Manager 2.1
- 1992 – MS LAN Manager 2.1a
- 1993 – MS LAN Manager 2.2
- 1994 – MS LAN Manager 2.2a
Many vendors shipped licensed versions, including:
Cryptanalysis[edit]
LAN Manager authentication uses a particularly weak method of hashing a user's password known as the LM hash algorithm, stemming from the mid 1980s when floppy viruses[clarification needed] were the major concern as opposed to potentially high-frequency attacks with feedback over a (high-bandwidth) network.[1] This makes such hashes crackable in a matter of seconds using rainbow tables, or in few hours using brute force. Its use in Windows NT was replaced by NTLM, of which older versions are still vulnerable to rainbow tables, but less vulnerable to brute force attacks. NTLM is used for logon with local accounts except on domain controllers since Windows Vista and later versions no longer maintain the LM hash by default.[1]Kerberos is used in Active Directory Environments.
The major weaknesses of LAN Manager authentication protocol are:[2]
- Passwords are not case sensitive. All passwords are converted into uppercase before generating the hash value. Hence it takes password, PassWord, PaSsWoRd, PASSword and other similar combinations same as PASSWORD converting all characters to uppercase. Password characters are also limited to a subset of 95 characters in the 256-byte ASCII character set.
- Password length is limited to maximum of 14 characters
- A 14-character password is broken into 7+7 characters and the hash is calculated for the two halves separately. This way of calculating the hash makes it exponentially easier to crack, as the attacker needs to brute force 7 characters twice instead of 14 characters. This makes the effective strength of a 14-characters password equal to only , or twice that of a 7-character password, which is significantly less complex than the theoretical strength of a 14-character password.
- If the password is 7 characters or less, then the second half of hash will always produce same constant value (0xAAD3B435B51404EE). Therefore, if the length of password is less than or equal to 7 characters, then a password length of 7 characters or less can be identified visibly without using tools.
- The hash value is sent to network servers without salting, making it susceptible to man-in-the-middle attacks such as replay the hash, and also allowing rainbow tables to be constructed.
LM hash details[edit]
LM hash (also known as LanMan hash or LAN Manager hash) is a compromised password hashing function that was the primary hash that Microsoft LAN Manager and Microsoft Windows versions prior to Windows NT used to store user passwords. Support for the legacy LAN Manager protocol continued in later versions of Windows for backward compatibility, but was recommended by Microsoft to be turned off by administrators; as of Windows Vista, the protocol is disabled by default, but continues to be used by some non-Microsoft SMB implementations.
Algorithm[edit]
The LM hash is computed as follows:[3][4]
- The user's password is restricted to a maximum of fourteen characters.[Notes 1]
- The user’s password is converted to uppercase.
- The user's password is encoded in the System OEM code page.[5]
- This password is null-padded to 14 bytes.[6]
- The “fixed-length” password is split into two 7-byte halves.
- These values are used to create two DES keys, one from each 7-byte half, by converting the seven bytes into a bit stream with the most significant bit first, and inserting a null bit after every seven bits (so
1010100
becomes10101000
). This generates the 64 bits needed for a DES key. (A DES key ostensibly consists of 64 bits; however, only 56 of these are actually used by the algorithm. The null bits added in this step are later discarded.) - Each of the two keys is used to DES-encrypt the constant ASCII string “
KGS!@#$%
”,[Notes 2] resulting in two 8-byte ciphertext values. The DES CipherMode should be set to ECB, and PaddingMode should be set toNONE
. - These two ciphertext values are concatenated to form a 16-byte value, which is the LM hash.
Security weaknesses[edit]
Although it is based on DES, a well-studied and formerly secure block cipher, the LM hash is not a true one-way function as the password can be determined from the hash because of several weaknesses in its design:[7] Firstly, passwords are limited to a maximum of only 14 characters, giving a theoretical maximum keyspace of with the 95 ASCII printable characters.
Secondly, passwords longer than 7 characters are divided into two pieces and each piece is hashed separately; this weakness allows each half of the password to be attacked separately at exponentially lower cost than the whole, as only different 7-character password pieces are possible with the same character set. By mounting a brute-force attack on each half separately, modern desktop machines can crack alphanumeric LM hashes in a few hours. In addition, all lower case letters in the password are changed to upper case before the password is hashed, which further reduces the key space for each half to .
The LM hash also does not use cryptographic salt, a standard technique to prevent pre-computed dictionary attacks. A time–memory tradeoffcryptanalysis attack, such as a rainbow table, is therefore feasible. In addition, any password that is shorter than 8 characters will result in the hashing of 7 null bytes, yielding the constant value of
0xAAD3B435B51404EE
, hence making it easy to identify short passwords on sight. In 2003, Ophcrack, an implementation of the rainbow table technique, was published. It specifically targets the weaknesses of LM encryption, and includes pre-computed data sufficient to crack virtually all alphanumeric LM hashes in a few seconds. Many cracking tools, e.g. RainbowCrack, L0phtCrack and Cain, now incorporate similar attacks and make cracking of LM hashes fast and trivial.A final weakness of LM hashes lies in their implementation — since they change only when a user changes their password, they can be used to carry out a pass the hash attack.
Workarounds[edit]
To address the security weaknesses inherent in LM encryption and authentication schemes, Microsoft introduced the NTLMv1 protocol in 1993 with Windows NT 3.1. For hashing, NTLM uses Unicode support, replacing
LMhash=DESeach(DOSCHARSET(UPPERCASE(password)), 'KGS!@#$%')
by NThash=MD4(UTF-16-LE(password))
, which does not require any padding or truncating that would simplify the key. On the negative side, the same DES algorithm was used with only 56-bit encryption for the subsequent authentication steps, and there is still no salting. Furthermore, Windows machines were for many years configured by default to send and accept responses derived from both the LM hash and the NTLM hash, so the use of the NTLM hash provided no additional security while the weaker hash was still present. It also took time for artificial restrictions on password length in management tools such as User Manager to be lifted.Contoh Microsoft Lan Manager
While LAN Manager is considered obsolete and current Windows operating systems use the stronger NTLMv2 or Kerberos authentication methods, Windows systems before Windows Vista/Windows Server 2008 enabled the LAN Manager hash by default for backward compatibility with legacy LAN Manager and Windows ME or earlier clients, or legacy NetBIOS-enabled applications. It has for many years been considered good security practice to disable the compromised LM and NTLMv1 authentication protocols where they aren't needed.[8]Starting with Windows Vista and Windows Server 2008, Microsoft disabled the LM hash by default; the feature can be enabled for local accounts via a security policy setting, and for Active Directory accounts by applying the same setting via domain Group Policy. The same method can be used to turn the feature off in Windows 2000, Windows XP and NT.[8] Users can also prevent a LM hash from being generated for their own password by using a password at least fifteen characters in length.[6]--NTLM hashes have in turn become vulnerable in recent years to various attacks that effectively make them as weak today as LanMan hashes were back in 1998.[citation needed]
Reasons for continued use of LM hash[edit]
Many legacy third party SMB implementations have taken considerable time to add support for the stronger protocols that Microsoft has created to replace LM hashing because the open source communities supporting these libraries first had to reverse engineer the newer protocols—Samba took 5 years to add NTLMv2 support, while JCIFS took 10 years.
Product | NTLMv1 support | NTLMv2 support |
---|---|---|
Windows NT 3.1 | RTM (1993) | Not supported |
Windows NT 3.5 | RTM (1994) | Not supported |
Windows NT 3.51 | RTM (1995) | Not supported |
Windows NT 4 | RTM (1996) | Service Pack 4[9] (25 October 1998) |
Windows 95 | Not supported | Directory services client (released with Windows 2000 Server, 17 February 2000) |
Windows 98 | RTM | Directory services client (released with Windows 2000 Server, 17 February 2000) |
Windows 2000 | RTM (17 February 2000) | RTM (17 February 2000) |
Windows ME | RTM (14 September 2000) | Directory services client (released with Windows 2000 Server, 17 February 2000) |
Samba | ? | Version 3.0[10] (24 September 2003) |
JCIFS | Not supported | Version 1.3.0 (25 October 2008)[11] |
IBM AIX (SMBFS) | 5.3 (2004)[12] | Not supported as of v7.1[13] |
Poor patching regimes subsequent to software releases supporting the feature becoming available have contributed to some organisations continuing to use LM Hashing in their environments, even though the protocol is easily disabled in Active Directory itself.
Lastly, prior to the release of Windows Vista, many unattended build processes still used a DOS boot disk (instead of Windows PE) to start the installation of Windows using WINNT.EXE, something that requires LM hashing to be enabled for the legacy LAN Manager networking stack to work.
See also[edit]
Notes[edit]
- ^If the password is more than fourteen characters long, the LM hash cannot be computed.
- ^The string “KGS!@#$%” could possibly mean Key of Glen and Steve and then the combination of Shift + 12345. Glen Zorn and Steve Cobb are the authors of RFC 2433 (Microsoft PPP CHAP Extensions).
References[edit]
- ^ abJesper Johansson. 'The Most Misunderstood Windows Security Setting of All Time'. TechNet Magazine. Microsoft. Retrieved 2 November 2015.
Although Windows Vista has not been released yet, it is worthwhile to point out some changes in this operating system related to these protocols. The most important change is that the LM protocol can no longer be used for inbound authentication—where Windows Vista is acting as the authentication server.
- ^Rahul Kokcha
- ^'Chapter 3 - Operating System Installation: The LMHash'. Microsoft Technet. Retrieved 2015-05-12.
- ^Glass, Eric (2006). 'The NTLM Authentication Protocol and Security Support Provider: The LM Response'. Retrieved 2015-05-12.
- ^'List of Localized MS Operating Systems'. Microsoft Developer Network. Retrieved 2015-05-12.
- ^ ab'Cluster service account password must be set to 15 or more characters if the NoLMHash policy is enabled'. Microsoft. 2006-10-30. Retrieved 2015-05-12.
- ^Johansson, Jasper M. (2004-06-29). 'Windows Passwords: Everything You Need To Know'. Microsoft. Retrieved 2015-05-12.
- ^ ab'How to prevent Windows from storing a LAN manager hash of your password in Active Directory and local SAM databases'. Microsoft Knowledge Base. 2007-12-03. Retrieved 2015-05-12.
- ^'Windows NT 4.0 Service Pack 4 Readme.txt File (40-bit)'. Microsoft. 1998-10-25. Retrieved 2015-05-12.
- ^'The Samba Team announces the first official release of Samba 3.0'. SAMBA. 2003-09-24. Retrieved 2015-05-12.
- ^'The Java CIFS Client Library'. Retrieved 2015-05-12.
- ^'AIX 5.3 Networks and communication management: Server Message Block file system'. IBM. 2010-03-15. p. 441. Retrieved 2015-05-12.
- ^'AIX 7.1 Networks and communication management: Server Message Block file system'. IBM. 2011-12-05. Retrieved 2015-05-12.
External links[edit]
Wikibooks has a book on the topic of: Reverse Engineering/Cracking Windows XP Passwords |
- Oechslin, Philippe (2003). 'Making a Faster Cryptanalytic Time-Memory Trade-Off'(PDF). Advances in Cryptology, CRYPTO 2003.
- 'Ophcrack, a well known password cracker'.
- 'Cain and Abel, password recovery tool for Microsoft Operating Systems'.
- mudge (1997-07-24). 'A L0phtCrack Technical Rant'. Archived from the original on 1997-07-24.
Retrieved from 'https://en.wikipedia.org/w/index.php?title=LAN_Manager&oldid=906293921'
Although, for the most part, setting up a wired network connection on a Windows 10 device is as easy as plugging in an Ethernet cable, connecting using a wireless adapter requires some additional steps depending on the security of the network.
Windows 10's Settings app that makes it super easy to manage many aspects of a Wi-Fi connection. Using the 'Wi-Fi' page in the 'Network & Security' section, you can connect and disconnect from a network, view configuration properties, change the network profile, manually add and remove network connections, set your connection as metered to reduce data usage on capped internet plans, and a lot more.
In this Windows 10 guide, we'll walk you through many ways you can manage wireless network connections on your device using the Settings app.
How to connect to a Wi-Fi network
Connecting to a wireless network is an easy process, you only need to know the network you want to connect and the security key to authenticate (sometimes also referred as a Wi-Fi password).
- Click the wireless icon in the notification area.
- Select the network you want to connect.
- Check the Connect automatically option.
- Click the Connect button.
- Enter the network security key.
- Click the Next button.
If the network flyout is not reporting any wireless network, you can try the steps shown below to turn off and on again Wi-Fi to see if that fixes the problem.
How to disconnect from a Wi-Fi network
Removing your device from a wireless network is also a straightforward process that can be done in a few different ways.
Disconnecting using the flyout menu
The easiest way to disconnect is using the network flyout menu.
- Click the wireless icon in the notification area.
- Select the network you're currently connected.
- Click the Disconnect button on the network connection.
Alternatively, you can click the quick action Wi-Fi button at the bottom to turn off the adapter and disconnect from the network using flyout menu.
Quick Tip: The same Wi-Fi button can also be found in the Action Center's Quick Actions section (Windows key + A).
If you don't select a schedule, then you'll need to enable the adapter manually by clicking the Wi-Fi button again from the flyout menu. Also, note that using the flygout menu, it's possible to turn on or off Airplane mode and Mobile hotspot.
Disconnecting using the Settings app
Alternatively, you can enable or disable Wi-Fi using the Settings app.
- Open Settings.
- Click on Network & Security.
- Click on Wi-Fi.
- Turn off the toggle switch for the adapter you want to disconnect.
- Use the drop-down menu to select an option to turn on the wireless adapter on schedule.
How to view a Wi-Fi connection properties
Sometimes, in order to troubleshoot a problem or set up an application, you'll need to know your network hardware information, such as network band, IP address, the name of the adapter and others. While there are a number of ways to find out this information, you can quickly identify these and other information about your wireless connection using the Settings app.
- Open Settings.
- Click on Network & Security.
- Click on Wi-Fi.
- Under the wireless network, click the Hardware properties link.
In the properties page, you'll find information, such as SSID, protocol, security type, network band and channel, IP and MAC address.
How to connect to a Wi-Fi network on range automatically
If you didn't select the option to connect to a wireless network automatically while setting up a new connection, or you enabled the option, but you don't need the configuration anymore, it's possible to control this feature using the Settings app.
- Open Settings.
- Click on Network & Security.
- Click on Wi-Fi.
- Click your current Wi-Fi connection.
- Turn on or off the Connect automatically when in range option.
How to change the Wi-Fi connection network profile
In order to increase network security, starting with the Windows 10 Fall Creators Update, you can now more easily set your wireless connection as Private on a network you trust, or Public on the network you don't trust, such as at a coffee shop or airport.
- Open Settings.
- Click on Network & Security.
- Click on Wi-Fi.
- Click your current Wi-Fi connection.
- Under 'Network profile,' select one of the two options:
- Public – makes your PC hidden from other devices on a public network and disables file and printer sharing.
- Private – makes your PC discoverable by other devices in a local network and allows them to use printer and file sharing (if it was configured).
If you're not running the Windows 10 Fall Creators Update, you'll see a Make this PC discoverable option, which works in the same way as the options shown in the above steps (toggle switch off means Public, and toggle switch on means Private).
How to set a Wi-Fi connection as metered
Out of the box, Windows 10 has unlimited access to the internet to download system and app updates, sync settings across your devices, connect to cloud services, and to connect you to the mighty internet.
The problem is that if you're on a limited internet connection, it's possible to go over the data cap very quickly. A metered connection helps to reduce Windows 10's data usage to prevent exceeding your data plan.
If you're connected to a limited data plan, you can use the Settings app to set your wireless connection as metered.
- Open Settings.
- Click on Network & Security.
- Click on Wi-Fi.
- Click your current Wi-Fi connection.
- Under 'Metered connection,' turn on the Set as metered connection toggle switch.
After completing the steps, Windows 10 will only have restricted access to an internet connection, which also prevents it from downloading updates. However, some critical updates may download over this type of connection.
In addition, using a metered connection will prevent the Start menu from downloading Live Tiles updates, and some apps will no longer receive updates automatically.
How to add or remove Wi-Fi connections
Using the Settings app is also possible to add or remove a Wi-Fi network manually in those cases when you may need to connect to a network that doesn't broadcast its SSID (Service Set Identifier), or when you need to set up a wireless connection beforehand to save time.
Adding a Wi-Fi network
- Open Settings.
- Click on Network & Security.
- Click on Wi-Fi.
- Click the Manage known networks link.
- Click the Add a new network button.
- Enter the network name.
- Using the drop-down menu, select the network security type.
- Check the Connect automatically option.
- Check the Connect even if the network is not broadcasting option.
- Click Save.
Once you've completed the steps, whenever your device is within range of the network, it'll connect automatically without any further steps.
Removing a Wi-Fi network
If you must remove (forget) a Wi-Fi network, the Settings app makes it a very straightforward process.
- Open Settings.
- Click on Network & Security.
- Click on Wi-Fi.
- Click the Manage known networks link.
- Select the Wi-Fi connection you want to remove.
- Click the Forget button (there is no confirmation dialog using this button, so make sure that you really want Windows 10 to forget this connection before clicking the button).
After completing the steps, your device will no longer try to connect with the network you've removed.
How to manage wireless services
The Wi-Fi settings page also offers a few nifty features for users that are always on the move.
Wi-Fi services
Windows 10 offers two additional features to help you get connected no matter where you are located. If you turn on the Find paid plans for suggested open hotspots near me toggle switch, then you'll be able to purchase data plans from the Windows Store form affiliated networks.
In addition, you can also turn on the Connect to suggested open hotspots toggle switch, which allows Windows 10 to connect automatically to open wireless networks, even connecting through landing pages thanks to a database of known networks.
While using suggested open hotspots is a good option, remember that some networks can be reliable but not secure.
Hotspot 2.0 networks
Hotspot 2.0 is a relatively new networking standard that makes connecting to public Wi-Fi networks a simple and secure process.
If you're in a public place like at a coffee shop, airport, or hotel, Hotspot 2.0 will identify and connect to the right network automatically without having to go through a list of networks which can be fake or malicious.
Hotspot 2.0 networks is enabled by default on Windows 10, but if you're planning to make use of this feature, you can go to Settings > Update & Security > Wi-Fi to make sure is enabled. You can also check this guide for more details.
Wrapping things up
While it's now possible to configure many wireless options using the Settings app, Windows 10 has yet to include every networking feature in this experience. This means that to change some options, such as advanced network adapter settings, power management, and set up specific protocols, you still need to use Control Panel.
More Windows 10 resources
For more helpful articles, coverage, and answers to common questions about Windows 10, visit the following resources: