|
Jan 30, 2003 Linux News - Issue #117 Jan 23, 2003 Linux News - Issue #116 Jan 16, 2003 Linux News - Issue #115 Jan 9, 2003 Linux News - Issue #114 Jan 2, 2003 Linux News - Issue #113 Dec 19, 2002 Linux News - Issue #112 Dec 12, 2002 Linux News - Issue #111 Dec 5, 2002 Linux News - Issue #110 Nov 28, 2002 Linux News - Issue #109 Nov 21, 2002 Linux News - Issue #108 Nov 14, 2002 Linux News - Issue #107 Nov 7, 2002 Linux News - Issue #106 Oct 31, 2002 Linux News - Issue #105 Oct 24, 2002 Linux News - Issue #104 Oct 17, 2002 Linux News - Issue #103 Oct 10, 2002 Linux News - Issue #102 Oct 3, 2002 Linux News - Issue #101 Sep 26, 2002 Linux News - Issue #100 Sep 19, 2002 Linux News - Issue #99 Sep 12, 2002 Linux News - Issue #98 Sep 5, 2002 Linux News - Issue #97 Aug 29, 2002 Linux News - Issue #96 Aug 22, 2002 Linux News - Issue #95 Aug 15, 2002 Linux News - Issue #94 Aug 8, 2002 Linux News - Issue #93 Aug 1, 2002 Linux News - Issue #92 Jul 25, 2002 Linux News - Issue #91 Jul 18, 2002 Linux News - Issue #90 Jul 11, 2002 Linux News - Issue #89 Jul 4, 2002 Linux News - Issue #88 Jun 27, 2002 Linux News - Issue #87 Jun 20, 2002 Linux News - Issue #86 Jun 13, 2002 Linux News - Issue #85 Jun 6, 2002 Linux News - Issue #84 May 30, 2002 Linux News - May 30, 2002 May 23, 2002 Pearl In The Shell May 16, 2002 Linux Filesystems - Part Two May 9, 2002 Inside The Linux Filesystem May 2, 2002 CD Burning Under Linux Apr 25, 2002 Star Office Vs. Open Office Apr 18, 2002 Surfing With Mozilla Apr 11, 2002 "We Don't Support Linux..." Apr 4, 2002 Visit The UNIX Library Mar 28, 2002 Linux and World Domination Mar 21, 2002 Working With Keyservers Mar 14, 2002 A Look At Public Key Cryptography Mar 7, 2002 Monitoring Systems With "vmstat" Feb 28, 2002 Star Office 6 Not to be Free for Linux? Feb 21, 2002 How Can Programming Benefit a Systems Administrator? Feb 14, 2002 Alias: It's Not Just a TV Show Feb 8, 2002 Using The diff and patch Utilities Jan 31, 2002 How To Detect Cracks Jan 24, 2002 Using Razor to Shave Away Spam Jan 17, 2002 Stomping Spam Jan 10, 2002 Sair Linux Courseware Review Jan 3, 2002 2002: The Year of the Penguin! Dec 27, 2001 UNIX Apps on a Windows Box? Dec 20, 2001 Directory Assistance Dec 13, 2001 How Do You Kill Zombies? Dec 6, 2001 Using Hard and Soft Symlinks Nov 29, 2001 Change Terminal-Based Apps Into Network Apps Nov 22, 2001 Adventures In Booting Nov 15, 2001 Getting To Know PAM Nov 8, 2001 Know Your Enemy Nov 1, 2001 Do Mulder and Scully Use X-Windows? Oct 25, 2001 A Quick Look at the RHCE Certification Oct 18, 2001 What's Up With Linux Certification? Oct 11, 2001 Express Yourself Regularly Oct 4, 2001 Advice For Lazy Penguins? Sep 27, 2001 NVIDIA Jumps On Linux Bandwagon Sep 20, 2001 Understanding DNS in a Linux Environment Sep 13, 2001 Be Careful With Binaries Sep 6, 2001 Party Like It's 999,999,999 Aug 30, 2001 Rooting Out Memory Hogs Aug 23, 2001 Spin Your 'Top' Aug 16, 2001 Keeping Time With NTP Aug 9, 2001 Supporting True Type Fonts Aug 2, 2001 Getting Perl To Fetch Jul 26, 2001 Who's The Man?! Jul 19, 2001 Adobe Cracks The DMCA Whip Jul 12, 2001 Due Processes Jul 5, 2001 Going Adobe Free Jun 28, 2001 Don't Send Mixed SIgnals Jun 21, 2001 Everything is a File. (almost) Jun 14, 2001 Know Your Partitions Jun 7, 2001 Where it's "at"! May 31, 2001 A Sneak Peek at RedHat 7.1 May 24, 2001 Scheduling Tasks With cron - Part 2 May 17, 2001 Scheduling Tasks With cron May 10, 2001 Open Source - Seeing Through The FUD May 3, 2001 A Look At Ximian's New Release Apr 26, 2001 Rev Up Your X-Windows Session Apr 19, 2001 Wrangling With GNU Cash Apr 12, 2001 Tame the syslogd Daemon Apr 5, 2001 Test Your Admin Skills At Honeynet Mar 29, 2001 Software RAID on Your Linux Box Mar 22, 2001 Prevent Disasters: Back It Up Mar 15, 2001 Notes From Underground! Mar 8, 2001 SuSE 7.1 - A First Look Mar 1, 2001 Certification Boot Camp Feb 22, 2001 Understanding Runlevels Feb 15, 2001 What Are The Advantages of Joining a LUG? Feb 8, 2001 Diving For Perls Feb 1, 2001 How To Secure Your Linux Installation Jan 25, 2001 Linux Problem Solving Jan 18, 2001 Stand up and Be Counted! Jan 11, 2001 2.4.0 is Here! Jan 4, 2001 When will Mom use Linux? Dec 28, 2000 The Year in Review Dec 21, 2000 The SourceForge Solution Dec 15, 2000 How to Compile and Install the New Kernel Dec 7, 2000 Put Your E-mail Into A Blackberry Basket Nov 30, 2000 Using Perl With Linux Nov 23, 2000 Working With MP3's Under Linux Nov 16, 2000 Apache 2.0 alpha 4 Nov 9, 2000 Dell loves Linux! Nov 2, 2000 What's Up With RedHat 7? |
===========================================================
LINUX NEWS
Resources & Links From www.CramSession.com
Thursday, May 23, 2002
===========================================================
-----------------
TABLE OF CONTENTS
-----------------
1) Sean's Notes
2) Linux News
This Just In... Reuters to Offer Linux
"Our Software Sucks So Bad It Must Be Kept Secret"
QCumber Returns From Bootcamp
Are You A Linux Waif?
3) Linux Resources
VMWare: /tmp out of space?
An Introduction to Linux Scheduling
Conducting Virtual Meetings With Linux
Daemon Monitoring Daemons
IPTables Usage
4) App o' the Week
~~~~~~~~~~~~~~~~~~~~~~~~ ADVERTISEMENT ~~~~~~~~~~~~~~~~~~~~~~~~~~
Get your certification now. Pay later! If you want to learn more
about Intense School's No money down and No payments for one year
financing, go to our website or call toll free 1-800-330-1446 to
speak to an Intense School Specialist.
http://ad.brainbuzz.com/?RC06&AIS04
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
For information on how to advertise in this newsletter
please contact mailto:adsales@CramSession.com or visit
http://cramsession.com/marketing/default.asp
===========================================================
1) Sean's Notes
===========================================================
People who've been on this list for a little while will
probably remember that I've got a Linux gateway on my cable
modem connection. Handy little thing, does a bit of email
and web, in addition to providing gateway services for the
handful of computers I've got laying around.
The only snag is that sometimes there are problems, and
things need to be done from the command line. Like today,
where my IP address was changed, and I had to renew my IP
address. Hard to do when you're at work and the box isn't on
the 'Net anymore. If I suspect something is wrong with the
connection, I've also got to take care of the basics before
calling tech support. When I'm at work, this involves
calling my wife, walking her through all the commands, and
so forth. What I'd like is a simple web interface she could
use that gives her relevant information, and the opportunity
to reset the network cards. Failing that, she reads off
what's on the screen, and I'm able to call the support line.
Normally, this would be a job for some CGI. I'm going to do
it a different way for two reasons:
1) Most of the commands will have to be executed as root, and
doing it from a web server that runs as an unprivileged UID
is just painful.
2) It's not as fun as the way I'm going to show you.
To accomplish this task, we're going to write a simple web
server. "What language?", you ask. "Bourne shell, of course!"
The big thing we're going to rely on is xinetd. Recall that
xinetd listens on the given port, and upon connection, calls
the appropriate program. The input and output of the program
is converted to network calls, which means that our simple
shell script won't need to know anything about networking.
First, we've got to choose a port number. "911" is
appropriate, so I'll add the following line to /etc/services
to map the service name to the port number.
diag 911/tcp # diagnosis web server
Then, set up xinetd:
/etc/xinetd.d/diag:
service diag
{
port = 911
socket_type = stream
wait = no
only_from = 192.168.1.0/24,127.0.0.1
bind = 192.168.1.10,127.0.0.1
user = root
server = /usr/sbin/911.sh
log_on_failure += USERID
disable = no
}
The only thing different about this one is that I've used
only_from as an IP based ACL, and "bind" to only bind this
port to my internal IP and to the loopback. This will prevent
outside people from accessing our little web server. Restart
xinetd to make the script take effect.
The "server" line above specifies the program that gets called
when a connection comes in. So, without further ado, let's
edit /usr/sbin/911.sh:
----------CUT-------------
#!/bin/bash
# Read in the request
IN="blah"
while [ -n "$IN" ]; do
read IN
# Strip EOL chars
IN=`echo $IN | tr -d '\r'`
echo $IN >> /tmp/webserver
done
# Push out the header
echo "HTTP/1.0 200 OK"
echo "Content-type: text/html"
echo
echo "<b>Here I am!</b>"
----------CUT-------------
The HTTP protocol is nice and simple. The web server answers
the client's call. The client sends headers, followed by a
blank line. The server returns a response code, headers, a
blank line, and then the raw data. The important header to
return is "Content-type", which lets the client know what's
coming. In this case it's text/html (HTML), but it could
just as easily be an image (image/gif).
So, the first thing we do in the script is enter a loop.
Each go around the loop, we'll read in something to the IN
variable. So that the first one goes through, we'll set it
to "blah".
Within the loop, read in one line from the input (read IN).
The line will also have an end of line character attached,
which has to be removed. Anything within backticks (` `) is
executed by the shell, and replaced by the output. In this
case, IN is assigned the result of "echo $IN | tr -d '\r'".
tr is the TRanslate command, -d means "delete the following
characters", specifically '\r', which is the end of line.
This is then dumped into /tmp/webserver for inspection.
In the event that the user gave us a blank line, $IN is zero
length, the -n (non zero length string) fails, and we know
we're done with the headers.
If all works out, you'll be able to hit
http://localhost:901/
and "Here I am!" should show up. If not, is 911.sh
executable? (chmod +x 911.sh). Is the /etc/xinetd.d/diag
file correct?
Turning our attention to /tmp/webserver, you can see what
the client sent. Here's the first couple of lines of mine:
GET / HTTP/1.1
Host: 192.168.1.10:911
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.9) Gecko/20020513
That first line is the one we're interested in, since it
tells us what the client is requesting. Hit
http://localhost:901/foo?something
and see what shows up in /tmp/webserver
GET /foo?something HTTP/1.1
There is no rule saying a file has to be there, so we'll
use this as a way to send commands to the web server.
Right before the "done" from the while loop, add the following
[ -z $URL ] && URL=`echo $IN | awk '/^GET/ {print $2}'`
That's a mouthful! Stuff between [ ] means that you're
testing, in this case "-z $URL" means "Is $URL zero length?".
If that evaluates to "true", meaning we haven't assigned
anything else to it, then the code on the right hand side
of the && gets executed.
Again, we'll use backticks to transform the input line,
this time using AWK. The general form of an AWK command is
/pattern/ { action }
This AWK says "If the string starts with GET, then output
the second column (the URL)". Feel free to add "echo $URL"
to the end of your script, and try again:
Here I am! You accessed /foo?something
To make things easier, we're going to make two assumptions
about this little application.
1) The action we're specifying is an alphanumeric string,
the tree is only one level deep. In this case, the
action is "foo".
2) The parameters, if any, are passed as a single string,
not MIME encoded, and appear after the question mark.
In this case, we're passing "something"
(Those that have programmed CGI will likely shudder at the
thought of encoding and decoding all those %XX in shell
script, so we'll avoid it entirely).
Right after the while loop to read the headers is finished
is where the URL will be split up.
ACTION=`echo $URL | awk -F \/ '{print $2}' | awk -F \? '{print $1'}`
PARAM=`echo $URL | awk -F \? '{print $2}'`
Please excuse the inelegance, it would have been a lot more
compact in PERL. Passing -F to AWK specifies the delimiter
(normally it's space or tab). Again, $N returns the N'th
column. To get the action, awk strips off anything after
the first /, also removing the optional question mark.
The PARAM is simply anything after the question mark.
The rest is all downhill from here. Now that we have an
action and an optional parameter, it's pretty easy to
execute the appropriate command.
case $ACTION in
ping) /bin/ping -c 5 $PARAM | awk -F, '/packet loss/ {print $3}' ;;
ifconfig) echo "<pre>"; /sbin/ifconfig -a; echo "</pre>" ;;
reset) echo "<pre>"; /sbin/network restart; echo "</pre>" ;;
*) echo "Whatchew talkin' 'bout, Willis?"
esac
A case statement allows you to execute different actions
based on a single variable. Here, if the action is ping,
we ping, only returning the packet loss stats. If it's
ifconfig, then give 'em an ifconfig. If it's reset, then
do that. A bit of well placed HTML, and we have a menu.
The script, in it's entirety:
----------CUT-------------
#!/bin/bash
# Read in the request
IN="blah"
while [ -n "$IN" ]; do
read IN
# Strip EOL chars
IN=`echo $IN | tr -d '\r'`
echo $IN >> /tmp/webserver
[ -z $URL ] && URL=`echo $IN | awk '/^GET/ {print $2}'`
done
ACTION=`echo $URL | awk -F \/ '{print $2}' | awk -F \? '{print $1'}`
PARAM=`echo $URL | awk -F \? '{print $2}'`
# Push out the header
echo "HTTP/1.0 200 OK"
echo "Content-type: text/html"
echo
echo "<b>Unauthorized users will be executed</b><br>"
echo "<a href=/ping?www.cramsession.com>Test remote connectivity</a><br>"
echo "<a href=/ifconfig>Interface Status</a><br>"
echo "<a href=/reset>Reset NICs</a>"
case $ACTION in
ping) /bin/ping -c 5 $PARAM | awk -F, '/packet loss/ {print $3}' ;;
ifconfig) echo "<pre>"; /sbin/ifconfig -a; echo "</pre>" ;;
reset) echo "<pre>"; /sbin/network restart; echo "</pre>" ;;
*) echo "Whatchew talkin' 'bout, Willis?" ;; # default case
esac
----------CUT-------------
Not bad for 30 lines of shell script!
To summarize, we used xinetd to handle all the networking --
the input and output of our script goes directly to the web
browser. The request from the browser was stripped apart,
which tells us the action the user wanted to perform, and any
optional parameters. Depending on the action, the script runs
certain commands. Security is handled by restricting who can
access the script.
The next time something happens to my cable modem, I don't
have to walk my wife through the command line. In the
browser she's already got open, I can have her do all the
troubleshooting I need.
Long live the Penguin,
Sean
mailto:swalberg@cramsession.com
===========================================================
2) Linux News
===========================================================
---------------------------------------
This Just In... Reuters to Offer Linux
---------------------------------------
"News and information provider Reuters Group Plc said on
Thursday it would offer customers the alternative of running
its market-data delivery system on Linux, in a bet that
banks and brokerages will shift trading to the upstart Linux
software." The announcement includes a mention that they'll
be enlisting the help of Red Hat and HP/Compaq.
http://www.reuters.com/news_article.jhtml?type=technologynews&Story
ID—3874
---------------------------------------------------
"Our Software Sucks So Bad It Must Be Kept Secret"
---------------------------------------------------
Well, that's not exactly what was said, but it's a good
summary. Microsoft is now claiming that any move to open up
their APIs or software would harm national security. I don't
know where to begin on this one.
http://www.eweek.com/article/0,3658,s%253D701%2526a%253D26875,00.as
p
------------------------------
QCumber Returns From Bootcamp
------------------------------
No, he hasn't joined the Army! Cramsession employee QCumber
took The Training Camp's seven day Linux bootcamp, and came
back a lean, mean, Linux using machine (and he's certified to
prove it). Thinking of some intense Linux training? Maybe this
is the choice for you.
http://infocenter.cramsession.com/TechLibrary/GetHtml.asp?ID88
---------------------
Are You A Linux Waif?
---------------------
Are you living with a Linux user? Here are some signs that
you might be affected by someone else's Linux habits.
http://www.linuxjournal.com/article.php?sidX68
===========================================================
3) Linux Resources
===========================================================
---------------------------
VMWare: /tmp out of space?
---------------------------
If you're like me, your disks are partitioned, and programs
don't have the luxury of storing several hundred megs in /tmp.
Normally, this isn't a problem except for VMWare. Here's how
to get it to use temporary space in the directory of your
choosing.
http://www.vmware.com/support/linux/troubleshooting/disk_mem_ts_lin
ux.html
------------------------------------
An Introduction to Linux Scheduling
------------------------------------
It's the scheduler's job to dole out time on the CPU to all
the processes you've got running. It's really an interesting
part of the OS, since there are many tradeoffs that have to
be made for efficient operation. This article goes through
some of the basics of task scheduling in Linux.
http://www.monolinux.com/modules/news/article.php?storyid8
---------------------------------------
Conducting Virtual Meetings With Linux
---------------------------------------
What happens when a simple conference call can't handle your
needs? Need to share slides or a desktop? Allow hundreds of
people to listen in? This series of articles looks at how it
can be done under Linux.
http://www.linuxplanet.com/linuxplanet/tutorials/4199/1/
-------------------
Daemon Monitoring Daemons
-------------------
This is a good explanation of a common technique where
programs on a system watch over other processes. If Apache
died in the middle of the night, wouldn't you rather have
your computer try starting it up again than be paged? Daemon
Monitoring Daemons will help you out.
http://linux.oreillynet.com/pub/a/linux/2002/05/09/sysadminguide.ht
ml
-------------------
IPTables Usage
-------------------
This article is about NAT and the IPTables features in the
2.4 kernel. The author makes use of some interesting
features, such as filtering on the content of the packet.
Well worth a read.
http://www.linuxjournal.com/article.php?sidX39
===========================================================
4) App o' the Week
===========================================================
This week's App is another game. I remember having an Air
Traffic Controller game for DOS some time ago that was very
addictive. Can't find it any more, but this game seems to be
quite close.
http://airtraffic.sourceforge.net/
===========================================================
(C) 2002 BrainBuzz.com, Inc. All Rights Reserved.
===========================================================
_______________________________________________________
This message is from CramSession.com.
You are currently subscribed to the
Hottest Linux News and Resources
as: sean@ertw.com
To un-subscribe from this newsletter by e-mail:
send a blank email message to:
mailto:leave-linuxnews-3825955Y@list.cramsession.com
-------------------------------------------------------
To Subscribe to this newsletter by e-mail:
send a blank email message to:
mailto:join-linuxnews@list.cramsession.com
_______________________________________________________
From -
Received: from list.brainbuzz.com (host14.bbz.tpf.qwest.net
[63.146.189.62]) by poochie.ertw.com (8.11.6/8.11.2) with SMTP id
g4UJJ7P19080 for <sean@ertw.com>; Thu, 30 May 2002 14:19:07 -0500
X-Mailer: ListManager Web Interface
Date: Thu, 30 May 2002 15:04:23 -0400
Subject: Linux News - May 30, 2002
To: sean@ertw.com
From: CramSession <listboss@list.cramsession.com>
List-Unsubscribe: <mailto:leave-linuxnews-3825955Y@list.cramsession.com>
Reply-To: "CramSession List Help" <listboss@list.cramsession.com>
Message-Id:
<LISTMANAGERSQL-3825955-6042-2002.05.30-15.06.31--sean#ertw.com@list.cramsession.com>
Content-Type: text/plain; CHARSET=US-ASCII
X-Evolution-Source: imap://sean@poochie/
Mime-Version: 1.0
===========================================================
LINUX NEWS
Resources & Links From www.CramSession.com
Thursday, May 30, 2002
===========================================================
-----------------
TABLE OF CONTENTS
-----------------
1) Sean's Notes
2) Linux News
Setting Up Hacker "Tripwires"
3) Linux Resources
Ximian CDs to Include Star Office
Linux vs SUN... Round N
Distros To Join Forces Against Red Hat
Linux Networks Much Cheaper Than Windows
X Clients, Servers, and Desktops, Oh My!
4) App o' the Week
~~~~~~~~~~~~~~~~~~~~~~ ADVERTISEMENT ~~~~~~~~~~~~~~~~~~~~~~~~~~~
Linux Administration Resource Kit: This $119.97 value is
available for just $9.99. Learn about installing Linux on one PC
or an entire network, integrating Linux into any network topology
and troubleshooting installation, configuration and networking
glitches.
Click for details!
http://ad.brainbuzz.com/?RC06&AIS20
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
For information on how to advertise in this newsletter
please contact mailto:adsales@CramSession.com or visit
http://cramsession.com/marketing/default.asp
==============================================================
1) Sean's Notes
==============================================================
Many admins are good about turning off the services that they
don't need, so that script kiddies don't take over their
computer a scant six hours after it is first plugged into the
Internet. Somewhat fewer make use of ipchains/iptables, and TCP
wrappers, to only allow trusted hosts to connect. Fewer yet
monitor for updates to software, and apply them (this latter
number is likely getting better now that distros are getting
better about notifying users). However, protecting your
computer is only half the security equation. We spend so much
time preparing for the inevitable attack that we forget to make
a plan to deal with those that are successful.
Periodic auditing goes a long way toward ensuring that you
haven't been the victim of a successful attack. The same
auditing procedures are also helpful in determining the extent
of the attack.
One program that is a lifesaver when it comes to auditing is
Tripwire (http://www.tripwire.org/). Tripwire takes a snapshot
of your system by storing checksums of critical files. If
anything about those files changes, it'll be flagged the next
time you run a check.
If your distribution doesn't include Tripwire, you can get it
from the link above.
The basic steps in using Tripwire are:
1. Set up your keys and files you want to monitor
2. Initialize the database
3. Periodically check for changes
4. Update database with approved changes, or act on unapproved ones
The last point bears mentioning -- Tripwire only tells you that
files have changed, it's up to you to figure out if it was a
legitimate change or not. If it was, Tripwire has the facilities
to update the main database.
When you install Tripwire, it gives you a shell script called
"twinstall.sh" (check /etc/tripwire/). When you run it, the
first thing it will do is prompt you (twice) to enter a
password for your site. After that, it prompts you to enter a
local keyfile passphrase (twice again). The difference between
them will soon be apparent. Make 'em difficult to guess. At
least 8 characters, use numbers and capitals too! Then, write
them down, and keep them in a safe place. If you read what it
spits out carefully, it suggests that you delete the two .txt
files (twcfg.txt and twpol.txt). You can do so safely; we'll
see soon how to retrieve them.
By default, Tripwire comes with a comprehensive list of files
that it monitors, so we'll jump over to initializing the
database.
# tripwire --init
Your system will get quite busy for a few minutes as tripwire
goes through your system and calculates checksums for the files
(checksums are one way functions, such that if you change any
of the input, such as the file, the output changes. Since a
checksum is usually around 20 bytes, it's a lot easier to store
than a copy of the file itself)
If you look in /var/lib/tripwire, you'll see a .twd file in
there. That's your Trip Wire Database. Between that, and the
files in /etc/tripwire, you've got a snapshot of your database.
Time to run our first check of the system:
# tripwire --check
The report that gets spit out is quite comprehensive. For
example, I ran the following:
# cd /sbin
# cp hdparm hdparm.tmp
# echo a >>hdparm
That made a copy of hdparm, and then modified the original to
have an 'a' at the end. Look what Tripwire found:
----------------------------------------------------------------
Rule Name: User binaries (/sbin)
Severity Level: 66
----------------------------------------------------------------
Added:
"/sbin/hdparm.tmp"
Modified:
"/sbin"
----------------------------------------------------------------
Rule Name: File System and Disk Administraton Programs (/sbin/hdparm)
Severity Level: 100
-----------------------------------------------------------------
Modified:
"/sbin/hdparm"
There's no fooling Tripwire!
You'll also notice that a lot of files were missing. That's the
trouble of going with defaults. The policy file is what tells
Tripwire what it's supposed to check. However, we erased the
plaintext version after running twconfig.sh, which means we'll
have to retrieve it first:
# twadmin --print-polfile > twpol.txt
# vi twpol.txt
# twadmin --create-polfile twpol.txt
Please enter your site passphrase:
Wrote policy file: /etc/tripwire/tw.pol
"twadmin" is used to manage policy files and the like.
--print-polfile prints the current policy to STDOUT, which I've
redirected to twpol.txt. Second line, I edit it to remove the
lines I don't want, or to add more. Then, I create the new
policy file. You'll notice I'm being prompted for the site
password -- all configuration files are signed by the site key,
so that no one can alter the list without your knowledge. By
contrast, the local key is used whenever you need to make
changes to the database. If a cracker were to think he were
smart by modifying the database, that change would be noticed.
Again, there's no fooling Tripwire!
If you want to update the policy and the database at one go,
you can use
# tripwire --update-policy twpol.txt
instead of the last step. Otherwise, reinitialize the database
with --init.
After the --check, you'll see that /var/lib/tripwire/report has
a .twr (Trip Wire Report) file in there. In order to update the
database, we'll need that.
# tripwire --update --twrfile \
/var/lib/tripwire/report/FILENAME.twr
You'll be presented with a copy of the report, along with
[X]
next to every change. If the X is left there, the change will
will be written to the database once you exit the editor (and
provide your local password, of course). Take it out, and it
won't be written to the database. Simple, eh?
Even though the complex system of signing databases and
configuration files will prevent against tampering, it doesn't
help the files from being deleted by a frustrated cracker.
Sure, you know you've been hacked, but you still don't know
what was changed. Therefore, keep a copy of all your keys on
a CD. Keep another copy of the database somewhere in case the
signature doesn't check out.
Using Tripwire is an effective way of making sure nothing has
been changed without your knowledge. Run the check every so
often (Red Hat puts it as a daily cron job).
Red Hat also gives some good instructions on how to use Tripwire:
http://www.redhat.com/docs/manuals/linux/RHL-7.3-Manual/ref-guide/c
h-tripwire.html
Security is all about diligence. Some time spent at the onset
can save you a lot of time later on.
Long live the Penguin,
Sean
mailto:swalberg@cramsession.com
===========================================================
2) Linux News
===========================================================
---------------------------------
Ximian CDs to Include Star Office
---------------------------------
For a mere $60, you'll be able to get a CD with both Ximian
GNOME, and Star Office. This is part of a recent partnership
announced earlier by Ximian and SUN. Solaris users also will
find that Ximian Connector will soon be available, allowing
you to connect to an Exchange 2000 server from your SUN
workstation.
http://ximian.com/about_us/press_center/press_releases/soffice_6.ht
ml
-----------------------
Linux vs SUN... Round N
-----------------------
I'm always interested in the way that the Linux community
interacts with the commercial heavyweights such as SUN.
Dr. Tormasov for SWSoft has responded to SUN propaganda
earlier, and his latest letter is incisive.
http://www.sw-soft.com/en/news/id%2c1111
--------------------------------------
Distros To Join Forces Against Red Hat
--------------------------------------
We're expecting that today Caldera, Conectiva, SuSE and
Turbolinux will announce that they're joining up forces to
work on a single distribution that can hopefully compete
against Red Hat. I'm not exactly thrilled by this, as SuSE
might come out on the short end of the stick. I'll be
looking forward to seeing the final announcement.
http://newsforge.com/newsforge/02/05/29/138258.shtml?tid=3
http://www.eweek.com/article/0,3658,sp1&a'405,00.asp
----------------------------------------
Linux Networks Much Cheaper Than Windows
----------------------------------------
"The study (which looked at purchasing and operating costs)
aimed to benchmark TCO for an organisation with 250 users,
over three years. The costing models included staff costs,
application licences, maintaining servers and workstations
and networking, as well as miscellaneous systems costs."
http://www.theregister.co.uk/content/5/25148.html
===========================================================
3) Linux Resources
===========================================================
----------------------------------------
X Clients, Servers, and Desktops, Oh My!
----------------------------------------
One of the things I've always found confusing about X-Windows
is the relationship between clients, servers, window managers,
desktop environments, and whatever else is needed to make it
all work. Here's a great explanation, along with other useful
stuff such as how to change your desktop environment... or is
that window manager?
http://www.redhat.com/docs/manuals/linux/RHL-7.2-Manual/ref-guide/s
1-x-clients.html
-------------------------------
Cramsession Security Newsletter
-------------------------------
Security has always been a great topic, which is why I'm
happy to see that Cramsession (the guys that bring you this
newsletter) have started up a security newsletter. First
issue has already gone out, so subscribe before you miss any
more!
http://newsletters.cramsession.com/signup/default.asp
----------------------
Need Some Case Studies
----------------------
Linux guru and frequent poster "linux_boy" has posted his
list of case studies and industry reports dealing with Linux.
Quite a bit of stuff here!
http://boards.cramsession.com/boards/vbm.asp?mV3625
----------------------------------
K-12 Linux Terminal Server Project
----------------------------------
Here's some great information on how one school used the
K-12 LTSP to cut costs and increase productivity in their
computer labs. Information on costs and other functionality
can be found here.
http://www.linuxplanet.com/linuxplanet/reports/4216/2/
-------------------
Linux and Aviation
-------------------
"This document is intended to provide pointers to software
packages that run under the Linux operating system and are
useful to private, commercial, or military pilots. The
ultimate goal is to enable pilots to use the Linux operating
system for all their aviation related computing needs,
totally eliminating the need for other operating systems.
I want to encourage pilots who are already using Linux to
contribute to this document, either by providing pointers to
existing software, or by writing new applications for Linux."
http://ibiblio.org/fplan/Aviation-HOWTO/Aviation-HOWTO.html
===========================================================
4) App o' the week
===========================================================
lbnamed is a name server written in perl. The difference is
that instead of reading from static files, requests can be
handled by perl code. For example, you might normally do
round robin DNS for a web farm. With lbnamed, you could have
it always return the server that has the lowest load average.
http://www.stanford.edu/~riepel/lbnamed/
===========================================================
(C) 2002 BrainBuzz.com, Inc. All Rights Reserved.
===========================================================
_______________________________________________________
This message is from CramSession.com.
You are currently subscribed to the
Hottest Linux News and Resources
as: sean@ertw.com
To un-subscribe from this newsletter by e-mail:
send a blank email message to:
mailto:leave-linuxnews-3825955Y@list.cramsession.com
-------------------------------------------------------
To Subscribe to this newsletter by e-mail:
send a blank email message to:
mailto:join-linuxnews@list.cramsession.com
_______________________________________________________
|