oinkmaster - update Snort signatures
oinkmaster.pl -o outdir [options]
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 modifications to specified
rules before updating your local rules files. It will also tell you the exact
changes from your previous rules.
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.
- -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
- 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 multiple 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).
- 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.
- Show valid command line arguments with short descriptions
- Enable interactive mode. You will be asked to approve the changes (if any)
before updating anything.
- 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";...
- Run in quiet mode. Nothing is printed unless there are changes in the
rules or if there are errors or warnings.
- 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 expressions.
- 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
- 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)
Download rules archive from default location specified in oinkmaster.conf and
put the new rules in /etc/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.
- 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 containing 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 section at the Snort web site to
find the right URL and more information. 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 message and exit.
That's why it's usually recommended to instead run Oinkmaster once for
each URL and use separate output directories. 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 immediately 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 downloaded 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.
- Run in verbose/debug mode. Should probably only be used in case you need
to debug your settings, like verifying complex modifysid statements. It
will also tell you if you try to use "disablesid" 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).
- Show version and exit.
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 passwords,
you should of course not send the output by e-mail without first encrypting
oinkmaster.pl -o /etc/snort/rules -b /etc/snort/backup 2>&1 | \
mail -s "subject" firstname.lastname@example.org
Grab three different rules archives and merge variables that exist
in downloaded snort.conf and foo.conf but not in local
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
archive 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://email@example.com:/home/user/rules.tar.gz \
> $TMP 2>&1; if [ -s $TMP ]; then mail -s "subject" \
firstname.lastname@example.org < $TMP; fi; rm $TMP)
If you find a bug, report it by e-mail to the author. Always include as much
information as possible.
The initial version was released in early 2001 under the name arachnids_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
Andreas Ostling <email@example.com>
The online documentation at http://oinkmaster.sf.net/ contains more information.