How to Disabling Password Recovery

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Why you need to set passwords on routers?

--> To defense against intruders

Why the passwords must be recovered?

>>> Sometimes passwords are forgotten. There are, however, some instances in which the widely known password recovery procedures should be disabled. When physical security is not possible or in a network emergency, password recovery can be disabled.

What is the key to recovering a password on a Cisco router?

>>> The key to recovering a password on a Cisco router is through manipulation of the configuration registers of the router. All router passwords are stored in the startup configuration, so if the configuration registers are changed properly, the startup configuration with the passwords stored within them can be bypassed.

What happens if you disable the password recovery?

>>> If you have disabled the password recovery mechanisms, you will not
be able to perform password recovery on the router. Disabling the password recovery procedure of a Cisco router is a decision that must be thought out ahead of time because the command used to disable password recovery also disables ROMMON.


How you can disable the password recovery?

>>> You can disable the Cisco password recovery procedure by issuing the no service
password−recovery command in global configuration mode:

CiscoRouter#config t
Enter configuration commands, one per line. End with CNTR/Z.
SecureRouter(config)#no service password−recovery
WARNING:
Executing this command will disable password recovery mechanism.
Do not execute this command without another plan for
password recovery.
Are you sure you want to continue? [yes/no]: yes

As you can see, the IOS reminds you of how serious disabling the password recovery procedures are with a warning message and a prompt allowing you to change your mind. To see the results of changing the password recovery feature, issue the show running−config command. The effects of issuing the command can be seen in the following configuration:

CiscoRouter#show run
Building configuration...
Current configuration:
!
version 12.0
service password−encryption
no service password−recovery
!
hostname CiscoRouter

After password recovery has been disabled and the configuration has been saved, the widely available password recovery procedure will not be available on the router. The following output verifies that password recovery is indeed disabled:

CiscoRouter#reload
Proceed with reload? [confirm]
00:14:34: %SYS−5−RELOAD: Reload requested
System Bootstrap, Version 11.3(2)XA4, RELEASE SOFTWARE (fc1)
Copyright (c) 1999 by cisco Systems, Inc.
TAC:Home:SW:IOS:Specials for info
PC = 0xfff14ee8, Vector = 0x500, SP = 0x680127b0
C2600 platform with 49152 Kbytes of main memory
PASSWORD RECOVERY FUNCTIONALITY IS DISABLED
program load complete, entry point: 0x80008000, size: 0x928024
Self decompressing the image : #######################....

If the no service password−recovery command has been issued on a Cisco router and the
passwords have been forgotten, you must contact your Cisco Technical Support Engineer to obtain help in gaining access into the router and enabling the password recovery process again.

http://networksecuritynotes.blogspot.com/2009/12/how-to-disabling-password-recovery.html

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Learn to Configure Enable Mode Security on Cisco Router

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To configure enable mode access, you can use one of two commands: enable password or enable secret. Both commands accomplish the same thing, allowing access to enable mode. However, the enable secret command is considered to be more secure because it uses a one−way encryption scheme based on the MD5 hashing function. Only use the enable password command with older IOS images and/or boot ROMs that have no knowledge of the newer enable secret command.




You configure an enable password by entering the enable password command in global configuration mode:

CiscoRouter#config t
Enter configuration commands, one per line. End with CNTL/Z.
CiscoRouter(config)#enable password VisaGoogla
CiscoRouter(config)#end
CiscoRouter#

The preceding configuration sets the enable password to VisaGoogla. The result of setting the enable password can be seen in the following output. From the user mode prompt, you must enter the enable command to gain access into privileged mode:

CiscoRouter>enable
Password: VisaGoogla
CiscoRouter#

Note: After you enter the enable command, the password you type at the password prompt will not be displayed. Be sure to type the password exactly as it is configured in the enable password command.

You configure an enable secret password by entering the following command in global configuration mode:

CiscoRouter#config t
Enter configuration commands, one per line. End with CNTL/Z.
CiscoRouter(config)#enable secret VisaGooglaSec
CiscoRouter(config)#end
CiscoRouter#

The preceding configuration sets the enable secret password to VisaGooglaSec. The result of setting the enable secret password can be seen in the following output. From the user mode prompt, you must enter the enable command to gain access into privileged mode, as follows:

CiscoRouter>enable
Password: VisaGooglaSec
CiscoRouter#

Note: After you enter the enable command, the password you type at the password prompt will not be displayed. Be sure to type the password exactly as it is configured in the enable password command.

Note: For security reason, we recommend you to use "enable secret password", because the secret password uses MD5 hashing function to encrypt your password, so it is more secure than "enable password"!!!

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Learn to configure Telnet Security on Cisco Router

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As you know, directly connecting to the console of a router is generally a relatively easy method for gaining access to the device; however, this method is inconvenient and not abundantly scalable. If console access is the only method available to gain access into the device, an administrator must always walk, drive, or fly to the physical location of the router and plug into the device's console port. Fortunately, there are methods for gaining access into the router from a remote location. The most common method of remote administration for a Cisco router is to use a Telnet session. Unlike with console access, there are four configuration requirements that must be met before you can use this method of access:

1. An enable password must be supplied.
2. The router must have an IP address assigned to a routable interface.
3. The routing table of the router must contain a route for the source of the Telnet packet.
4. Under line configuration mode, a vty password must be supplied.

The steps involved in defining Telnet security are similar to the steps used to configure console security. An example of configuring the fourth requirement (after the first three have been met) can be seen here:

CiscoRouter#config t
Enter configuration commands, one per line. End with CNTL/Z.
CiscoRouter(config)#line vty 0 4
CiscoRouter(config−line)#password CisViSa
CiscoRouter(config−line)#login
CiscoRouter(config−line)#end
CiscoRouter#

As mentioned in my previous post about learning to configure Console Security, Cisco routers also maintain a local user authentication database, which can be used to authenticate users who directly connect to the console port of a router. Here is an example of configuring the router to use the local user database for uthentication of users who attempt to access the router via the console:

!
username Visa privilege 15 password 0 Vipsw
username Googla privilege 12 password 0 Goopsw
username Yaha privilege 8 password 0 Yapsw
!
line vty 0 4
login local

The result is that, when a user telnets to the router with this configuration, they will be prompted to enter a username and password before being allowed to gain access into the router.

Routers can also restrict Telnet access to authorized users with the use of an access list. The access list is then applied to the virtual terminal ports of the router with the access−class command. This allows you to restrict Telnet access from a particular IP address or a subnet of IP addresses. Use the following steps to this method of security:
Use the access−list global configuration command to configure an access list that permits the specific hosts that are allowed Telnet access.

1. Use the access−class access−list−number {in|out} command to apply the access list to the virtual terminal ports.
2. In the following example, the router is configured to allow only three hosts Telnet access on each of the available virtual terminal ports:

CiscoRouter#config t
Enter configuration commands, one per line. End with CNTL/Z.
CiscoRouter(config)#access−list 20 permit 192.168.0.10
CiscoRouter(config)#access−list 20 permit 192.168.0.11
CiscoRouter(config)#access−list 20 permit 192.168.0.12
CiscoRouter(config)#line vty 0 4
CiscoRouter(config−line)#access−class 20 in
CiscoRouter(config−line)#end
CiscoRouter#

Note: Console and Telnet security is not preconfigured for you by default. One of your first configuration steps when you initially set up your router should be to configure each of these interfaces. To see more access-list commands visit here!

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Learn to configure Console Security on Cisco Router

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The console port is used to attach a terminal directly into the router. By default, no security is applied to the console port and the setup utility does not prompt you to configure security for console access. Cisco routers have many different modes of operation, one of which is user mode. When you first access the router via the console port, the router will prompt you for a password, if one has been configured. After successfully supplying the password, you are logged into user mode on the router. When a Cisco router is in user mode, the router will display its hostname followed by the greater than symbol. Here is an example of user mode access:

CiscoRouter>

User mode has limited functionality. Enable mode, also called privileged mode, can be accessed by typing the enable command. If passwords have been configured to access this level of the IOS, the router prompts you for the correct password. When a Cisco router is in enable mode, the router will display its hostname followed by the pound sign. Here is an example of enable mode access:

CiscoRouter#

Cisco passwords are case sensitive. The simplest and most direct way to connect to the network device is to use a direct connection to the console port of a router or switch. You can configure a console password to authenticate users for user mode access by entering the following commands:

CiscoRouter#config t
Enter configuration commands, one per line. End with CNTL/Z.
CiscoRouter(config)#line con 0
CiscoRouter(config−line)#password CisRoutPsw
CiscoRouter(config−line)#login
CiscoRouter(config−line)#end

The preceding configuration sets the user mode password to CisRoutPsw. Cisco routers also maintain a local user authentication database, which can be used to authenticate users who connect directly to the console port of a router. Here's an example of configuring the router to use the local user database for authentication of users who attempt to access the router via the console:

!
username Visa privilege 15 password 0 Vipsw
username Googla privilege 12 password 0 Goopsw
username Yaha privilege 8 password 0 Yapsw
!
line con 0
login local
transport input none
!

The preceding configuration defines three users: Visa, Googla, and Yaha. Each user has an associated privilege level defined for their respective login credentials and has a password that is associated with their username. This allows Visa to log into the router with a username of Visa and a password of Vipsw. Because Visa's privilege level defines the maximum privilege level that can be configured on the router, Visa is considered to be the super−user. Googla has a privilege
level of 12 and the password Goopsw.

Assignment of privilege levels is discussed in detail later in next post!

By assigning Googla a privilege of 12, the administrator can limit the functionality that Googla may have on the router. That's also the case for Yaha. When a user plugs into the console port of a router configured with local authentication, they are first prompted for their username; after successfully passing the correct username to the router, they are then prompted for the password that is associated with that username. The following example details these steps:

User Access Verification
Username: Visa
Password: Vipsw
CiscoRouter#

Now, what do you think would happen if you were to attempt to log in with the username of Visa and the password that is associated with Googla? You would suspect that the router would deny you access. This example details this attempt:

User Access Verification
Username: Visa
Password: Goopsw
% Login invalid
Username:

From this, you can see that you must supply the password that is associated with the username with which you are attempting to gain access.

Warning: When using local authentication and assigning privilege levels, you must be careful to associate the correct username with the correct privilege level.
Anyone who logs in with a privilege level that is equal to 2 or above is logged directly into privileged mode.

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Becareful with your Routers on HTTP Access

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Before going through the problem, the following word should be considered to be read first:

What is HTTP?

-> HTTP stands for Hypertext Transfer Protocol, is an application-level protocol for distributed, collaborative, hypermedia information systems.Its use for retrieving inter-linked resources led to the establishment of the World Wide Web. HTTP uses port 80 as its default port. As you can see on Web Browser with the link address, Example: http://NetworkSecurityNotes.blogspot.com, my Network Security blog's address that can be browsed or viewed by using HTTP protocol. More additionally, on your Web Browser address bar, you can also browse any website with link address, Example: http://NetworkSecurityNotes.blogspot.com:80, the address will sill be redirected to the address http://NetworkSecurityNotes.blogspot.com. That's the port 80 is HTTP's default port.

How About HTTP Access?

-> Well, I just give a short definition what HTTP Access is. HTTP Access is a process of an access by using HTTP protocol.

Why on the Routers need to becareful with HTTP Access?

As you know on routers with Cisco IOS software equipped with a Web browser user interface that allows you to issue commands into the router via the Web interface. The Web browser user interface can be customized and tailored to your business environment. The HTTP server is disabled by default; when it's enabled, it introduces some new security vulnerabilities into your network. The HTTP server function, when it's enabled, gives all client devices with logical connectivity to the router the ability to monitor or modify the configuration of the router. All that needs to reside on the client is a software package that interprets packets on port 80. This is obviously a major security issue. So, the most concern with HTTP Access is about the security vulnerabilities when the HTTP Server is enabled on Routers.

So, How to take control of these security vulnerabilities?

The router software allows you to change the default port (port 80) that the HTTP server is running on. You can also configure an access list of specific hosts that are allowed Web access to the router and apply the access list to the HTTP server. Authentication of each user provides better security if you elect to use the router's HTTP server functions. Authentication can take place by one of four different methods:
> AAA: commonly stands for “Authentication, Authorization and Accounting"
> Enable: Indicates that the configured enable password is used for authentication. This is the default authentication method.
> Local: Indicates that the locally configured security database is used for authentication.
> TACACS+: stands for Terminal Access Controller Access-Control System Plus, a protocol which provides access control for routers, network access servers and other networked computing devices via one or more centralized servers. This option indicates that the Terminal Access Controller Access system is used for authentication.

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Understanding about Route Filtering to securing network

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As my previous post about Routing Protocol Authentication, today post, I would like to find out about Route Filtering to securing network. 

What is Route Filtering?

Route Filtering is the process by Router, in which the certain routes are not considered for inclusion in the local route database, or not advertised to one's neighbours. During configuring Router, the Network Administrator need to be aware of which type of network route should be allowed to enter the Network Local or to go out to the remote Network. 

There are two Types of Filtering:

1.Input filtering

Input filtering is a filter is applied to routes as they are learned from a neighbour. A route that has been filtered out is discarded straight away, and hence not considered for inclusion into the local routing database.

2.Output filtering

Output filtering, a filter is applied to routes before they are announced to a neighbour. A route that has been filtered out is never learned by a neighbour, and hence not considered for inclusion in the remote route database.

Why Route Filtering? 

1.Route filtering enables the network administrator to keep tight control over route advertisements.

2.Route filters ensure that routers will advertise as well as accept legitimate networks. They work by regulating the flow of routes that are entered into or advertised out of the routing table.

3.Filtering the networks that are advertised out of a routing process or accepted into the routing process helps to increase security because, if no route is advertised to a downstream or upstream neighbor, then no route apparently exists to the network. 

4.Using Route Filtering to prevent routers on a local network from learning about routes that are dynamically advertised out on the interface, you can define the interface as passive. Defining an interface as passive keeps routing update messages from being sent through a router interface, preventing other systems on the interface from learning about routes dynamically from this router. You can configure a passive interface for all IP routing protocols except Border Gateway Protocol (BGP).

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Routing Protocol Authentication

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What is Routing Protocol? 

A routing protocol is a protocol that specifies how routers communicate with each other, disseminating information that enables them to select routes between any two nodes on a computer network, the choice of the route being done by routing algorithms. Each router has a prior knowledge only of networks attached to it directly. A routing protocol shares this information first among immediate neighbors, and then throughout the network. This way, routers gain knowledge of the topology of the network.

The term routing protocol may refer specifically to one operating at layer three of the OSI model, which similarly disseminates topology information between routers.

Many routing protocols used in the public Internet are defined in documents called RFCs.

There are two major types of routing protocols, some with variants: link-state routing protocols and (path vector protocols) distance-vector routing protocols.

The specific characteristics of routing protocols include:

-the manner in which they either prevent routing loops from forming or break them up if they do

-the manner in which they select preferred routes, using information about hop costs

-the time they take to converge

-how well they scale up

-many other factors

Routing protocol authentication?

Routing protocol authentication prevents the introduction of false or unauthorized routing messages from unapproved sources. With authentication configured, the router will authenticate the source of each routing protocol packet that it receives from its neighbors. Routers exchange an authentication key or a password that is configured on each router. The key or password must match between neighbors.

There are two types of routing protocol authentication: plain text authentication and Message Digest 5 (MD5) authentication. 

1.Plain text authentication is generally not recommended because the authentication key is sent across the network in clear text, making plain text authentication susceptible to eavesdropping attempts. 

2.MD5 authentication creates a hash value from the key; the hash value instead of the actual password is exchanged between neighbors, preventing the password from being read because the hash, not the password, is transmitted across the network.

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Securing your network with SNMP

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After my previous post about Physical and Logical security, today I want to show you about securing the network with SNMP.

What is SNMP?

SNMP stands for Simple Network Management Protocol, is a component of the Internet Protocol Suite as defined by the Internet Engineering Task Force (IETF). It is used in network management systems to monitor network-attached devices for conditions that warrant administrative attention. SNMP is alsow known as an application−layer protocol that helps to facilitate the exchange of management information between network devices. SNMP helps network administrators to manage network performance, and troubleshoot network problems, and plan for network growth.

3 basic components of SNMP:

An SNMP-managed network consists of three key components:

1. Managed devices: A managed device is a network node that contains an SNMP agent and that resides on a managed network. Managed devices collect and store management information and make this information available to NMSs using SNMP. Managed devices, sometimes called network elements, can be any type of device including, but not limited to, routers, access servers, switches, bridges, hubs, IP telephones, computer hosts, and printers.

2. Agents: An agent is a network-management software module that resides in a managed device. An agent has local knowledge of management information and translates that information into a form compatible with SNMP.

3. Network-management stations (NMSs): An NMS executes applications that monitor and control managed devices.NMSs provide the bulk of the processing and memory resources required for network management. One or more NMSs may exist on any managed network.

An SNMP managed device has various access levels:

+Read−only: Allows read access of the Management Information Base (MIB) on the managed device.

+Read/write: Allows read and write access of the Management Information Base on the managed device.

+Write−only: Allows write access of the Management Information Base on the managed
device.

Cisco IOS software supports 3 versions of SNMP: SNMPv1, SNMPv2c, and SNMPv3.

SNMPv1 and SNMPv2c

These two versions use a community based form of security. The group of managers eables to access the agent is defined by an access list and password.

How about SNMPv2c?

SNMPv2c support includes a bulk retrieval echanism and more detailed error message reporting to management stations. The bulk retrieval mechanism supports the retrieval of large quantities of information, minimizing the number of polls required. The SNMPv2c improved error handling support includes a larger number of error codes that distinguish different kinds of error conditions. Error return codes in SNMPv2c report the error type.

How is SNMPv3?

SNMPv3 provides for both security models and security levels. A security model is an authentication strategy that is set up for a user and the group in which the user resides. A security level is the permitted level of security within a security model. A combination of a security model and a security level will determine which security mechanism is employed when an SNMP packet is handled.

==>You can read more about SNMP at http://www.cisco.com/en/US/docs/internetworking/technology/handbook/SNMP.html

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Setting Banner Messages

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Router(config)#banner motd #
*********************************************
UNAUTHORIZED ACCESS PROHIBITED!
*********************************************
#

You can use banner messages to issue statements to users, indicating who is and who is not allowed access into the router. Banner messages should indicate the seriousness of an attempt to gain unauthorized access into the device and should never reflect to the user that gaining unauthorized access is acceptable. If possible, recite certain civil and federal laws that are applicable to unauthorized access and let users know what the punishment would be for accessing the device without express written permission. If possible, have certified legal experts within the company review the banner message.

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Configuring Password Encryption

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All Cisco console and Telnet passwords configured on the router are stored in plain text within the configuration of the router by default, thus making them easily readable. If someone issues the show running−config privileged mode command, the password is displayed. Another instance when the password can easily be read is if you store your configurations on a TFTP server, the intruder only needs to gain access into the TFTP machine, after which the intruder can read the
configuration with a simple text editor. Password encryption stores passwords in an encrypted manner on the router. The encryption is applied to all configured passwords on the router.

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Disabling Password Recovery

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Setting passwords is the first line of defense against intruders. Sometimes passwords are forgotten and must be recovered. All Cisco password recovery procedures dictate that the user performs the password recovery process from the console port of the router or switch. There are, however, certain circumstances in which the widely available password recovery procedure should be disabled. One such circumstance is an emergency Add, Move, or Change (AMC), whereby a
networking device needs to be in a location that does not have the proper mechanisms in place for physical security, thus allowing an intruder a greater chance of circumventing traditional security measures.

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Setting Privilege Levels

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Privilege levels associate router commands with each security level configured on the router. This allows for a finer granularity of control when restricting user access. There are 16 privilege levels contained within the router operating system. Level 2 to level 14 are customizable and allow you to configure multiple privilege levels and multiple passwords to enable certain users to have access to specific commands.

But most users of Cisco routers are familiar with only two privilege levels:

• User EXEC mode — privilege level 1


• Privileged EXEC mode — privilege level 15

When you log in to a Cisco router under the default configuration, you’re in user EXEC mode (level 1). From this mode, you have access to some information about the router, such as the status of interfaces, and you can view routes in the routing table. However, you can’t make any changes or view the running configuration file.

Because of these limitations, most Cisco router users immediately type enable to get out of user EXEC mode. By default, typing enable takes you to level 15, privileged EXEC mode. In the Cisco IOS, this level is equivalent to having root privileges in UNIX or administrator privileges in Windows. In other words, you have full access to the router.

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Securing Telnet Access

This blog is created for network security review, study and understanding about network related issues only! The blog is mainly focus on Network Security Notes about Network, Network Security, Network Technology, Network Labs review related Cisco and Microsoft technology ,Network Threats, Types of Network Threats, Network Alerts, Enterprise Security Policy and Audits, Security Policy and Audits,Logical Security, Physical and Logical Security, Physical Security,Cisco Products Review, Microsoft Products review, Cisco Routers, Routers Security, Console Access, Telnet Access, Network Attack, Network Attack report, Network management, Anti-virus, Network Security with Anti-virus, and All About Network Security... Thanks for your visit!

Telnet (Telecommunication network) is a network protocol used on the Internet or local area networks. It was developed in 1969 beginning with RFC 15 (Request For Comments 15 ) and standardized as IETF (Internet Engineering Task Force) STD 8, one of the first Internet standards. Typically, Telnet provides access to a command-line interface on a remote machine.

Telnet is a protocol that allows a user to establish a remote connection to a device. After connected to the remote device, you are presented with a screen that is identical to the screen that would be displayed if you were directly connected to the console port. Telnet ports on a router are referred to as virtual terminal ports. Telnet is really no different from a console connection, and as such, the

proper logical security mechanisms should be put into place to ensure that only responsible personnel are allowed Telnet access. Virtual terminal ports support many different methods for authenticating a user and allowing access. Some of the methods are included in the following list:

· Vty password
· Local user database
· TACACS+
· RADIUS

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Securing Console Access

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It's important to put the proper physical security mechanisms into place. If the proper physical

security mechanisms are not in place, an intruder could potentially bypass all other logical security mechanisms and gain access to the device. If an intruder can gain access to the administrative interface of the router, he could view and change the device's configuration and gain access to other networking equipment. The first thing you should do to prevent intruders from accomplishing is to set a console password. If the intruder has already gained physical access to the device, he'll attempt to gain network access through the console port first. The console port supports many different methods for authenticating a user and allowing access, some of which are listed here:
· Console password
· Local user database
· TACACS+ (Terminal Access Controller Access-Control System Plus) : is a protocol which provides access control for routers, network access servers and other networked computing devices via one or more centralized servers. TACACS+ provides separate authentication, authorization and accounting services.
· RADIUS(Remote Authentication Dial In User Service) : is a networking protocol that provides centralized access, authorization and accounting management for people or computers to connect and use a network service. When a person or device connects to a network often "Authentication" is required. Networks or services not requiring authentication are said to be anonymous or open.

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Physical and Logical Security

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Physical and logical security staffs, both tasked with protecting enterprise assets, are seeing increased technology and budgetary overlaps.

Physical and logical security include the following:

. Securing console access
· Securing Telnet access
· Setting privilege levels
· Disabling password recovery
· Configuring password encryption
· Setting banner messages

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Enterprise Security Policy and Audits

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The main purpose of a security policy is to inform anyone that uses the enterprise's network of the requirements for protecting the enterprise's technology and information assets.

A security policy should not determine how an enterprise operates; instead, the business of the enterprise should dictate how a security policy is written. Business opportunities are what drive the need for security in the first place.

The policy should contain:

1.Acceptable use policy—Spells out what users are allowed and not allowed to do on the various components within the network; this includes the type of traffic allowed on the network. The policy should be as explicit as possible to avoid any ambiguity or misunderstanding.

2.Remote access policy—Spells out to users acceptable or unacceptable behavior when they have connected to the enterprise via the Internet, a dial−up connection, a virtual private network (VPN), or any other method of remote connectivity.

3.Incident handling policy—Addresses planning and developing procedures to handle incidents before they occur. The incident handling policy can be contained within the actual security policy.

4.Internet access policy—Defines what the enterprise considers to be ethical, proper use of its Internet connection.

5.Email policy—Defines the acceptable use of the enterprise's email systems, including personal emails and Web−based email.

6.Physical security policy—Defines controls that pertain to physical device security and access.

After you've completed the enterprise security policy, the last step is to perform regular audits. Audits not only give you a baseline by which to judge what is deemed as normal activity or network behavior, they also, in many cases, produce results that will be the first alert in the detection of a security breach. Noticing unusual events within the network can help to catch intruders before they can cause any further damage.

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Types of Threats

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The methods hackers and crackers use to gain unauthorized access into network devices are known as threats.

1.Unauthorized access—A network intruder can gain unauthorized access to networking devices through a variety of means, three of which are as follows:

Physical—If attackers have physical access to a machine, more often than not, they will be able to get in. The techniques used to gain access range from accessing the device via the console to physically taking apart the system.

System—System access assumes that the intruder already has a user account on the system. Proper privileges should be granted to the user such that he or she is authenticated and authorized only to do that which is deemed to be a function of his or her job duties.

Remote—Remote access involves intruders who attempt to penetrate the system remotely from across the Internet, through a dial−up connection, or on local or wide area network. This type of intruder usually has no account privileges.

2.Eavesdropping—Eavesdropping is used to capture TCP/IP or other protocol packets, thus allowing the intruder to decode the contents of the packet using a protocol analyzer. "Packet sniffing" is a more common term used to describe the act of eavesdropping. Eavesdropping leads to information theft, like stolen credit card and social security numbers.

3.Data manipulation—Data manipulation is simply the act of altering files on computers, vandalizing a Web site, or replacing FTP files.

4.Protocol weakness—The most−used protocol in circulation today is TCP/IP. This protocol was designed a long time ago. As a result, a number of its design flaws can lead to possible security problems, such as smurf attacks, IP spoofing, TCP sequence number prediction, and SYN floods. The IP protocol itself is a very trusting protocol; therefore, hackers are free to forge and change IP data.

5.Session replay—Intruders can eavesdrop on one or more users involved in a communication session and manipulate the data in such a manner according to the hack they are trying to perform.

These are just some types of security threats to give you a general idea of the number and types of methods intruders have at their disposal.

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