Date: Thu, 16 Feb 2012 12:26:52 -0500 From: Glen Barber <glen.j.barber@gmail.com> To: Miroslav Lachman <000.fbsd@quip.cz> Cc: freebsd-security@freebsd.org Subject: Re: periodic security run output gives false positives after 1 year Message-ID: <20120216172652.GA1989@schism.local> In-Reply-To: <4F3D3722.2000904@quip.cz> References: <4F3D3722.2000904@quip.cz>
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On Thu, Feb 16, 2012 at 06:04:34PM +0100, Miroslav Lachman wrote: > Hi, > > I see it many times before, but never take a time to post about it. > > Scrips in /etc/periodic are grepping logs for yesterday date, but > without specifying year (because some logs do not have year logged). > > This results in false positive alerts in security e-mails from our > lightly loaded servers, where logs are not enough rotated. > > For example /var/log/auth.log is 62KB (838 lines) and contains entries > for almost 2 years. > > Today I get following alert: > > Feb 15 22:36:03 XXX sshd[89758]: Invalid user t1na from xxx.xxx.xxx.xxx > Feb 15 22:50:56 XXX sshd[89850]: Invalid user medina from xxx.xxx.xxx.xxx > Feb 15 22:50:57 XXX sshd[89852]: Invalid user student from xxx.xxx.xxx.xxx > Feb 15 22:50:58 XXX sshd[89854]: Invalid user student from xxx.xxx.xxx.xxx > > (hostname and IP are replaced by X) > > But looking in to auth.log I found zero entries from yesterday - Feb 15 > entries were logged 1 year ago! > > So I propose to set all daemons / syslog to log year too (as %Y) and > change yesterday=`date -v-1d "+%b %e "` to yesterday=`date -v-1d "+%b > %e %Y"` in periodic scripts. > > The affected scripts are: > 460.status-mail-rejects > 470.status-named > 800.loginfail > 900.tcpwrap > > Maybe some others, I did just a quick grep -rsn 'date -v-1d' > /etc/periodic and I don't know the logic used in other script to get > yesterday messages. > > What do you think about it? > Rotating the appropriate logs daily/weekly/monthly/whatever will silence these false alarms. Glen
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