For tripwire, how would I have the report e-mailed only when a violation is found

My solution to getting a lot of tripwire reports from a lot of hosts is to have them all sent to an address which stacks them up in a file, then run a simple job on them that reports just the host name and violation counts, and only emails that report if there are any hosts with a non-zero violation count.

Firstly, all the hosts send their reports to the address [email protected]. That's easy to arrange from each of the crontab entries; I do it with:

# check the tripwires
[email protected]
3 1 * * *  /usr/sbin/tripwire --check

Secondly, on the mail server, I have an aliases entry that says:

# tripwire report autoprocessing
tripwire:   /var/tmp/tripwire

Thirdly, I have a cron job that runs every morning to process the contents of that file, and another that runs every evening to remove it (so I'm only looking at the most recent outputs):

# report problems with nightly tripwire runs
2 7 * * *  /usr/local/bin/tripwire-check
45 23 * * *  rm -f /var/tmp/tripwire

And here's the contents of /usr/local/bin/tripwire-check; it's very simple:

#!/bin/tcsh
grep "Total violation" /var/tmp/tripwire | grep -vw 0 > /dev/null || exit 0
egrep 'Host name|Total vio' /var/tmp/tripwire | mail -s "NIGHTLY TRIPWIRE VIOLATIONS `date +%Y%m%d`" [email protected]

The first grep exits without any mail or output IFO all the lines that contain a violation count also contain the number 0, as a whole word; the second, which is only invoked if the first line fails, produces the terse summary email and sends it to me.

And finally, here's a sample output when there's an error to report:

Subject: NIGHTLY TRIPWIRE VIOLATIONS 20050401
Date:   Fri, 1 Apr 2005 07:02:00 +0100
To:     [email protected]
From:   root <[email protected]>

Host name: fw03b.company.com
Total violations found: 0
Host name: je01b.company.com
Total violations found: 0
Host name: ms01.company.com
Total violations found: 1
Host name: fw05a.company.com
Total violations found: 0
Host name: fw02b.company.com
Total violations found: 0
Host name: fw01b.company.com
Total violations found: 0
Host name: je02o.company.com
Total violations found: 0
Host name: je01a.company.com
Total violations found: 0
Host name: fw04a.company.com
Total violations found: 0
Host name: fw04b.company.com
Total violations found: 0
Host name: je02p.company.com
Total violations found: 0
Host name: fw02a.company.com
Total violations found: 0
Host name: fw03a.company.com
Total violations found: 0
Host name: rp01a.company.com
Total violations found: 0
Host name: rp01b.company.com
Total violations found: 0
Host name: je03o.company.com
Total violations found: 0
Host name: db03.company.com
Total violations found: 0
Host name: lb02p.company.com
Total violations found: 15
Host name: rp02o.company.com
Total violations found: 23
Host name: as05.company.com
Total violations found: 0
Host name: db02.company.com
Total violations found: 0

Hope that's of some use.

Tripwire has an option to suppress reports that have no errors (MAILNOVIOLATIONS), it is found in the config file...

You could set up 2 different twcfg files, one with MAILNOVIOLATIONS set to TRUE, and one with this option set to FALSE

MAILNOVIOLATIONS =true   (or false)

Then your cronjob could run tripwire using the -c flag to select the twcfg file

Daily report crontab:

30 12 * * 1,2,3,4,5,6 /usr/sbin/tripwire --check -c PATH_TO_DAILY_CFG_FILE | mail -s "Tripwire report for `uname -n`, errors found" [email protected]

Sunday report crontab:

30 12 * * 0 /usr/sbin/tripwire --check -c PATH_TO_WEEKLY_CFG_FILE | mail -s "Weekly Tripwire report for `uname -n`" [email protected]

This way, your daily cronjob would run tripwire using the config file that only emails reports if violations are found, and your weekly cronjob would email you a report regardless.

p.s. the above crontab commands are from a system using Debian, you may need to edit the path to your Tripwire binary.

I know I already chose Mr. MadHatter's submission as the answer but after some thinking, I've thought of something else that might work. Does anyone see why this would not work?

tripwire_out=`/usr/sbin/tripwire --check`; test -z "`echo $tripwire_out | grep 'Total violations found: 0'`"&& echo $tripwire_out

I've tested it out in the shell and it works as intended. However, I have not replaced the tripwire cron job yet.

What do you guys think?