Rsh Post: 302222990

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Operating Systems AIX Rsh Post 302222990 by bakunin on Friday 8th of August 2008 05:02:21 AM

08-08-2008

Registered User

Quote:

Originally Posted by vjm

But as you said Bakunin it doesn't asks for password which is a security hazard.

Errrm, no.

The problem is not the failure to ask for a password. rlogin in fact asks for a password if the user/host is not mentioned in the .rhosts-file. And if you use ssh and have exchanged the keys it does not ask for a password either.

The problem is that rlogin (like telnet and all the other classical connections) transfer all the data without any encryption and therefor you can find out the password sent (and all the other things done) as a third party by listening to the traffic on the line. While ssh encrypts the whole communication so you could listen to it and still not understand.

It is a common misconception that more passwords create more security. True, a password will identify someone, but having to enter a password over and over doesnt make the system more secure than having to enter it once. In fact having to remember several passwords will reduce the security because as the number of passwords increases people are more likely to write them down somewhere where they can be found by intruders.

I hope this helps.

bakunin

bakunin

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LEARN ABOUT LINUX

pam_pwhistory

PAM_PWHISTORY(8)						 Linux-PAM Manual						  PAM_PWHISTORY(8)

NAME

       pam_pwhistory - PAM module to remember last passwords

SYNOPSIS

       pam_pwhistory.so [debug] [use_authtok] [enforce_for_root] [remember=N] [retry=N] [authtok_type=STRING]

DESCRIPTION

       This module saves the last passwords for each user in order to force password change history and keep the user from alternating between the
       same password too frequently.

       This module does not work together with kerberos. In general, it does not make much sense to use this module in conjunction with NIS or
       LDAP, since the old passwords are stored on the local machine and are not available on another machine for password history checking.

OPTIONS

       debug
	   Turns on debugging via syslog(3).

       use_authtok
	   When password changing enforce the module to use the new password provided by a previously stacked password module (this is used in the
	   example of the stacking of the pam_cracklib module documented below).

       enforce_for_root
	   If this option is set, the check is enforced for root, too.

       remember=N
	   The last N passwords for each user are saved in /etc/security/opasswd. The default is 10.

       retry=N
	   Prompt user at most N times before returning with error. The default is 1.

       authtok_type=STRING
	   See pam_get_authtok(3) for more details.

MODULE TYPES PROVIDED

       Only the password module type is provided.

RETURN VALUES

       PAM_AUTHTOK_ERR
	   No new password was entered, the user aborted password change or new password couldn't be set.

       PAM_IGNORE
	   Password history was disabled.

       PAM_MAXTRIES
	   Password was rejected too often.

       PAM_USER_UNKNOWN
	   User is not known to system.

EXAMPLES

       An example password section would be:

	   #%PAM-1.0
	   password	required       pam_pwhistory.so
	   password	required       pam_unix.so	  use_authtok

       In combination with pam_cracklib:

	   #%PAM-1.0
	   password	required       pam_cracklib.so	  retry=3
	   password	required       pam_pwhistory.so   use_authtok
	   password	required       pam_unix.so	  use_authtok

FILES

       /etc/security/opasswd
	   File with password history

SEE ALSO

       pam.conf(5), pam.d(5), pam(8) pam_get_authtok(3)

AUTHOR

       pam_pwhistory was written by Thorsten Kukuk <kukuk@thkukuk.de>

Linux-PAM Manual						    06/04/2011							  PAM_PWHISTORY(8)