1 Explain the differences between the passwords used to secu

1) Explain the differences between the passwords used to secure a Cisco Router?

Solution

User Passwords

-User passwords and most other passwords in Cisco IOS configuration files are encrypted using a scheme that is very weak by modern cryptographic standards.

-Although Cisco does not distribute a decryption program, at least two different decryption programs for Cisco IOS passwords are available to the public on the Internet

The scheme used by Cisco IOS for user passwords was never intended to resist a determined, intelligent attack. The encryption scheme was designed to avoid password theft via simple snooping or sniffing. It was never intended to protect against someone conducting a password-cracking effort on the configuration file.

Because of the weak encryption algorithm, it has always been Cisco\'s position that customers should treat any configuration file containing passwords as sensitive information, the same way they would treat a cleartext list of passwords.

enable secret and enable password

The enable password command should no longer be used. Use the enable secret command for better security. The only instance in which the enable password command might be tested is when the device is running in a boot mode that does not support the enable secret command.

Enable secrets are hashed using the MD5 algorithm. As far as anyone at Cisco knows, it is impossible to recover an enable secret based on the contents of a configuration file (other than by obvious dictionary attacks).

Which Cisco IOS Image Supports enable secret?

Look at your boot image using the show version command from your normal operating mode (Full Cisco IOS image) to see whether the boot image supports the enable secret command. If it does, remove enable password. If the boot image does not support enable secret, note the following caveats:

Setting an enable password might be unnecessary if you have physical security so that no one can reload the device to the boot image.

If someone has physical access to the device, he can easily subvert the device security without needing to access the boot image.

If you set the enable password to the same as the enable secret, you have made the enable secret as prone to attack as the enable password.

If you set enable password to a different value because the boot image doesn\'t support enable secret, your router administrators must remember a new password that is used infrequently on ROMs that don\'t support theenable secret command. By having a separate enable password, administrators may not remember the password when they are forcing downtime for a software upgrade, which is the only reason to log in to boot mode.

Other Passwords

Almost all passwords and other authentication strings in Cisco IOS configuration files are encrypted using the weak, reversible scheme used for user passwords.

To determine which scheme has been used to encrypt a specific password, check the digit preceding the encrypted string in the configuration file. If that digit is a 7, the password has been encrypted using the weak algorithm. If the digit is a 5, the password has been hashed using the stronger MD5 algorithm.

For example, in the configuration command:

The enable secret has been hashed with MD5, whereas in the command:

The password has been encrypted using the weak reversible algorithm.