OINKMASTER(1)OINKMASTER(1)NAMEoinkmaster - update Snort signatures
SYNOPSIS
oinkmaster.pl -o outdir [options]
DESCRIPTION
Oinkmaster is simple tool that helps you keep your Snort rules current
with little or no user interaction. It downloads a tarball containing
the new rules and can then enable, disable or even make arbitrary modi‐
fications to specified rules before updating your local rules files.
It will also tell you the exact changes from your previous rules.
OPTIONS
The only required argument to Oinkmaster is -o outdir where outdir is
the directory to put the new rules files in. This should be where you
keep your rules locally. The downloaded files will be compared to the
ones in here before possibly overwriting them.
Optional arguments:
-b dir If the rules have been modified, a tarball of your old rules
will be put in dir before overwriting them with the new files.
No backup is done if no file has changed or if Oinkmaster is
running in careful mode.
-c Run in careful mode. This means that Oinkmaster will only check
for updates and print them, but not update anything.
-C cfg Use this configuration file instead of the default. If not
specified, oinkmaster.conf will be looked for in /etc/ and then
/usr/local/etc/. You can specify multiple -C cfg to load multi‐
ple configuration files. They will be loaded in order of
appearance on the command line. If an option is redefined, it
overrides the previous value (except for the "url" option, as
you are allowed to specify multiple URLs).
-e Enable rules that are disabled by default in the downloaded
rules archive by removing all the leading "#" from them. If
there are any disabled rules in the archive, they will stay that
way unless you use this option. Remember that they are disabled
for a reason (they may not even work), so use this option with
care.
-h Show valid command line arguments with short descriptions
-i Enable interactive mode. You will be asked to approve the
changes (if any) before updating anything.
-m Minimize/simplify the diff when printing result for modified
rules by removing common leading and trailing parts of the old
and new rule so it's easier to see the actual change. A few
characters to the left and to the right of the change are also
printed so you get some context. The rev keyword is ignored
when the comparison and removal of common parts is performed
because it would often make the whole idea fail. (If you feel
it's important to be able to verify that the rev number has
increased when a rule has been updated, do not use the minimized
diff mode.)
Normally when a rule has changed the entire old and new versions
are printed, but the actual change between them can be hard to
see if the rules are long, complex and many.
The normal output could look like this:
Old: alert tcp any any -> any 22 (msg: "foo"; flags: A+; rev:1;)
New: alert tcp any any -> any 123 (msg: "foo"; flags: A+; rev:2;)
When using -m it would instead look something like:
Old: ...any any -> any 22 (msg: "foo";...
New: ...any any -> any 123 (msg: "foo";...
-q Run in quiet mode. Nothing is printed unless there are changes
in the rules or if there are errors or warnings.
-Q Run in super-quiet mode. This is the same as -q but even more
quiet when printing the results (the "None." stuff is not
printed). It will also suppress some other warning messages such
as those for duplicate SIDs and non-matching modifysid expres‐
sions.
-r Check for rules files that exist in the output directory but not
in the downloaded rules archive, i.e. files that may have been
removed from the distribution archive.
-s Leave out details when printing results (aka bmc mode). This
means that the entire added / removed / modified rules will not
be printed, just their SID and msg string, plus the filename.
Non-rule changes are printed as usual. This output mode could be
useful for example if you send the output by email to people who
don't really care about the details of the rules, just the fact
that they have been updated. Example output when running with -s
[+++] Added rules: [+++]
1607 - WEB-CGI HyperSeek hsx.cgi access (web-cgi.rules)
1775 - MYSQL root login attempt (mysql.rules)
[///] Modified active rules: [///]
302 - EXPLOIT Redhat 7.0 lprd overflow (exploit.rules)
304 - EXPLOIT SCO calserver overflow (exploit.rules)
305 - EXPLOIT delegate proxy overflow (exploit.rules)
306 - EXPLOIT VQServer admin (exploit.rules)
-S file
Used in conjuction with with -U to specify which file(s) in the
downloaded archive(s) to search for new variables. When not
specified, snort.conf is checked. You may specify multiple -S
file to search for new variables in multiple files.
-T Check the configuration file(s) for fatal errors and then exit.
Possible warning messages are printed as well.
-u url Download the rules archive from url instead of the location
specified in the configuration file. It must start with
file://, ftp://, http://, https:// or scp:// and end with
".tar.gz" or ".tgz". The file must be a gzipped tarball contain‐
ing a directory named "rules", holding all the rules files. It
must not contain any symlinks. You can also point to a local
directory with dir://<directory>. For the official Snort rules,
the URL to use depends on the version of Snort you run and it
might also require registration. Visit the rules download sec‐
tion at the Snort web site to find the right URL and more infor‐
mation. Remember to update the URL when upgrading to a new major
version of Snort.
You may specify multiple -u url to grab multiple rules archives
from different locations. All rules files in the archives will
be put in the same output directory so if the same filename
exists in multiple archives, Oinkmaster will print an error mes‐
sage and exit. That's why it's usually recommended to instead
run Oinkmaster once for each URL and use separate output direc‐
tories. If -u url is specified, it overrides any URLs specified
in the configuration file(s). Note that if multiple URLs are
specified and one of them is broken, Oinkmaster will exit imme‐
diately without further processing. This can be good or bad,
depending on the situation.
-U file
Variables (i.e. "var foo bar" lines) that exist in downloaded
snort.conf but not in file will be added to file right after any
other variables it may contain. Modified existing variables are
not merged, only new ones. file is normally your production
copy of snort.conf (which should not be a file that is updated
by Oinkmaster the normal way). This feature is to prevent Snort
from breaking in case there are new variables added in the down‐
loaded rules, as Snort can not start if the rules use variables
that aren't defined anywhere. By default when using -U , the
file snort.conf in the downloaded archive is search for new
variables but you can override this with the -S file argument.
If you download from multiple URLs, Oinkmaster will look for a
snort.conf in each downloaded rules archive.
-v Run in verbose/debug mode. Should probably only be used in case
you need to debug your settings, like verifying complex modi‐
fysid statements. It will also tell you if you try to use "dis‐
ablesid" on non-existent SIDs. Warnings about using
enablesid/localsid/modifysid on non-existent SIDs are always
printed unless running in quiet mode, as those are usually more
important (using "disablesid" on a non-existent rule is a NOOP
anyway).
-V Show version and exit.
EXAMPLES
Download rules archive from default location specified in oinkmas‐
ter.conf and put the new rules in /etc/rules/:
oinkmaster.pl -o /etc/rules
Grab rules archive from local filesystem and do not print anything
unless it contains updated rules:
oinkmaster.pl -u file:///tmp/rules.tar.gz -o /etc/rules -q
Download rules archive from default location, make backup of old rules
if there were updates, and send output by e-mail. (Note however that if
you plan on distributing files with Oinkmaster that could be considered
sensitive, such as Snort configuration files containing database pass‐
words, you should of course not send the output by e-mail without first
encrypting the content.):
oinkmaster.pl -o /etc/snort/rules -b /etc/snort/backup 2>&1 | \
mail -s "subject" user@example.com
Grab three different rules archives and merge variables that exist in
downloaded snort.conf and foo.conf but not in local
/etc/snort/snort.conf:
oinkmaster.pl -u file:///tmp/foo.rules.tar.gz \
-u http://somewhere/rules.tar.gz -u https://blah/rules.tar.gz \
-o /etc/rules -S snort.conf -S foo.conf -U /etc/snort/snort.conf
Load settings from two different files, use scp to download rules ar‐
chive from a remote host where you have put the rules archive, merge
variables from downloaded snort.conf, and send results by e-mail only
if anything changed or if there were any error messages. It assumes
that the "mktemp" command is available on the system:
TMP=`mktemp /tmp/oinkmaster.XXXXXX` && \
(oinkmaster.pl -C /etc/oinkmaster-global.conf \
-C /etc/oinkmaster-sensor.conf -o /etc/rules \
-U /etc/snort.conf \
-u scp://user@example.com:/home/user/rules.tar.gz \
> $TMP 2>&1; if [ -s $TMP ]; then mail -s "subject" \
you@example.com < $TMP; fi; rm $TMP)
FILES
/etc/oinkmaster.conf
/usr/local/etc/oinkmaster.conf
BUGS
If you find a bug, report it by e-mail to the author. Always include as
much information as possible.
HISTORY
The initial version was released in early 2001 under the name arach‐
nids_upd. It worked only with the ArachNIDS Snort rules, but as times
changed, it was rewritten to work with the official Snort rules and the
new name became Oinkmaster.
AUTHOR
Andreas Ostling <andreaso@it.su.se>
SEE ALSO
The online documentation at http://oinkmaster.sf.net/ contains more
information.
January 14, 2004 OINKMASTER(1)
