This is an old revision of the document!
Author | Japheth Cleaver |
Compatibility | Xymon 4.2.3 |
Requirements | perl, unix |
Download | None |
Last Update | 2015-11-09 |
Originating thread here: http://www.xymon.com/archive/2010/06/msg00148.html
A small script that checks “sslcert” tests and tries to verify that the common name (“CN=”) in the resulting ssl certificate matches the URL that we tried to reach (eg, https://secure.example.com/) It reports the status under a new test name, “sslname”, or can optionally send a 'modify' message to alter the original “sslcert” test. Wildcard certificates are taken into account, since we're matching using extended grep.
Client side
Server side
1. Copy the script into the ext/
directory (or wherever you're storing external scripts) and edit your tasks.cfg file by adding a new block:
# "sslname" runs the ssl certificate checker to verify that sslcert test results match
# the URL we tried to access
#
[sslname]
ENVFILE /etc/xymon/xymonserver.cfg
NEEDS xymond
CMD /etc/xymon/ext/sslname.sh
LOGFILE /var/log/xymon/sslname.log
INTERVAL 5m
- sslname.sh
#!/bin/sh
# sslname.sh v2
#
# Retrieve a list of all "sslcert" tests, which come out of any SSL-enabled
# check Xymon does using a built-in (probably https, but also things like imaps)
#
# After getting this list, we go through each one looking for the common-
# name that the certificate responded with, verifying that it matched the
# url we were trying to reach in the originating test. Normally this means
# the address for the http test, but it could be just the hostname in the event
# of another SSL service.
#
# Japheth Cleaver <cleaver@terabithia.org>
# No warranty. YMMV. Use at your own risk.
#
# First pass: 2010-08-02
# http://xymonton.org/monitors:sslname.sh
#
# v2 2012-04-27 -- update from hobbit -> xymon and optionally use "modify"
# instead of our own status
[ -z "$XYMON" ] && -x /usr/bin/xymoncmd && exec /usr/bin/xymoncmd $0 $*
# Set some defaults - I'm running this from xymonlaunch, YMMV
[ -z "$TESTNAME" ] && TESTNAME=sslname
[ -z "$XYMSRV" ] && XYMSRV=0.0.0.0
[ -z "$COLOR" ] && COLOR="clear"
[ -z "$XYMON" ] && XYMON=/usr/bin/xymon
# Modify the sslcert test result, or create our own?
# MODIFY=1
# Get a list of all valid sslcert tests
SSLHOSTS="`$XYMON $XYMSRV \"xymondboard test=sslcert fields=hostname\"`"
[ -z "$SSLHOSTS" ] && exit 0
# Loop over them and compare the common name with any URL we can find
for THISHOST in $SSLHOSTS ; do
# Return the details of this host's sslcert data, unescaping on the way
SSLDATA="`$XYMON $XYMSRV \"xymondboard host=^$THISHOST test=sslcert fields=hostname,msg\" | perl -pe 's/>/>/g, s/</</g, s/&/&/g;' -e 's/\\\n/\n/g;'`"
THISCOMMA="`echo $THISHOST | sed -e 's/\./,/g'`"
# Find the common name...
# TODO: We should loop over all common names and try to figure out what the relevant URLs are below
# For now, we sort and take the first one.
COMMONNAME="`echo \"$SSLDATA\" | grep -v issuer: | grep CN= | perl -pe 's/^.*CN=([\w\.\-\*]+).*$/\1/' | sort | uniq | head -n 1`"
if [ -z "$COMMONNAME" ] ; then
echo "Couldn't find a 'common name' for $THISHOST..." >&2
continue
fi
# echo " -- Common name for $THISHOST is '$COMMONNAME'"
# Isolate what hostname we were trying to access and store as URL,
# if found. The HUMANURL is the full string, including any port number
export URL="`echo \"$SSLDATA\" | grep -c https://`"
if [ $URL -eq 1 ] ; then
# Great, a simple https address to look at
URL="`echo \"$SSLDATA\" | grep https:// | perl -pe 's#^.*https://([\w\.\-]+)(:\d+)?/.*$#\1#'`"
HUMANURL="`echo \"$SSLDATA\" | grep https:// | perl -pe 's#^.*(https://[\w\.\-]+(:\d+)?/).*$#\1#'`"
else
URL=$THISHOST
HUMANURL=$THISHOST
fi
ISMATCH="`echo $URL | grep -cE $COMMONNAME`"
# Check if we're just modifying the existing status
if [ -n "$MODIFY" ] ; then
[ $ISMATCH -ne 1 ] && $XYMON $XYMSRV "modify ${THISCOMMA}.sslcert red $TESTNAME Certificate $COMMONNAME does NOT match $HUMANURL"
continue
fi
# Build our Xymon report
if [ $ISMATCH -eq 1 ] ; then
STATUS="SSL cert ok"
COLOR="green"
BODY="&green $HUMANURL matches certificate $COMMONNAME"
else
STATUS="SSL cert name MISMATCH"
COLOR="red"
BODY="&red $HUMANURL does NOT match certificate $COMMONNAME
<A HREF=\"$XYMONWEBHOST$XYMONSERVERCGIURL/svcstatus.sh?HOST=$THISHOST&SERVICE=sslcert\">See 'sslcert' test results</A>"
fi
# Send results to Xymon
$XYMON $XYMSRV "status ${THISCOMMA}.${TESTNAME} ${COLOR} `date` - ${STATUS}
${BODY}"
done
# fin
exit 0
Known Bugs and Issues
sslcert tests that are a result of multiple SSL_enabled services tested by xymonnet should be tested individually against the URLs (or server name) in question and the worst state flagged.
Wildcards are handled via regex, however this will lead to a false negative if your wildcard is for a more root-ward subdomain. Eg, *.example.net will be seen as an acceptable common name for https://server.dc.example.net/ when it really isn't.
This was targeted mainly at https:// tests; “sslcert” results from other types of tests (imaps, smtps, pop3s, etc) are tested against the server name only. YMMV.