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Re: reduction of brute force login attempts via SSHthrough iptables --hashlimit


From: Benjamin Bennett <ben () psc edu>
Date: Thu, 02 Mar 2006 11:36:14 -0500

On Thu, 2006-03-02 at 17:23 +0100, GroundZero Security wrote:
Well i dont want to destroy your happy time where you can feel superior, but
if you would read the manpage of lastb you would notice that this approach wont work at all.
lastb just shows successfull logins! not all the attempted logins....we discussed that before though,
so better pay attention next time.

Another thing is that on many systems btmp is not present and thus lastb wouldnt work even if it
would show failed logins.

NAME
       last, lastb - show listing of last logged in users

SYNOPSIS
       last [-R] [-num] [ -n num ] [-adiox] [ -f file ] [name...]  [tty...]
       lastb [-R] [-num] [ -n num ] [ -f file ] [-adiox] [name...]  [tty...]

DESCRIPTION
       Last  searches  back  through  the  file /var/log/wtmp (or the file designated by the -f flag) and displays a 
list of all
users logged in (and out)
       since that file was created.
       ....

...and a little farther down...

  "Lastb is the same as last, except that by default it shows a  log  of
the file /var/log/btmp, which contains all the bad login attempts."

as you can see it only logs "logged in" users not all those that tried. so your script is useless.

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