Tag Archives: SIEM

Alienvault OSSIM: Asset page broken after upgrading to 4.4

After upgrading OSSIM to 4.4.0 (or 4.4.1) the Asset section may show the error:

Operation was not completed due to an database error

If you then check the status of the table on the CLI you’ll find the table is missing!

alienvault:~# ossim-db
mysql> select * from asset limit 1;
ERROR 1146 (42S02): Table 'alienvault.asset' doesn't exist
mysql> quit

To resolve re-run the SQL upgrade script which should recreate your table (albeit empty):

cd /usr/share/ossim/include/upgrades
gunzip 4.4.0_mysql.sql.gz
gunzip 4.4.1_mysql.sql.gz
ossim-db < 4.4.0_mysql.sql
ossim-db < 4.4.1_mysql.sql

Then reload the Assets page and it should work.

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How to run Alienvault OSSIM 4.2 in (custom) text mode

This is also a fix for

  1. GUI installer hanging on “Configure network” when you try and enter the IP address
  2. Configuring disk setup
  3. Selecting which components to install

These options were available in 4.1 but were removed from the boot menu of the installer in 4.2.

The options are still there though. To run the custom text installer do the following:

  1. Boot from the OSSIM 4.2 CD
  2. At the installer menu highlight USM 4.2 (the top one)
  3. Hit the TAB button
  4. Edit the kernel boot line so it shows as (all one line)
/install.amd/vmlinux preseed/file=/cdrom/preseed debian/priority=low preseed/interactive=true vga=normal initrd=/install.amd/initrd.gz quiet ALLinONEauto --

5. Then hit enter to boot into custom text mode.

For the lazy out there you can also:

  1. Put the 4.1 installer CD in the CDROM and boot to the menu.
  2. Swap the CD over and put in the 4.2 CD
  3. Select custom text mode from the menu

It’ll then boot.

Q.E.D?

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Updating snort and openvas rules

Openvas and snort rules in Alienvault OSSIM are deployed as part of the updates. However, you can update them more frequently directly from the Openvas and Snort repositories.

Openvas Plugin Update Script

Most of this is directly from the Alienvault configuration guide, but in assorted places. Here’s the script to update the openvas rules:

#!/bin/sh 
openvas-nvt-sync --wget /etc/init.d/openvas-scanner restart 
perl /usr/share/ossim/scripts/vulnmeter/updateplugins.pl migrate

Save this as a .sh file (e.g. update-openvas-plugins.sh) and chmod to 700 with owner root

chmod 700 update-openvas-plugins.sh 
chown root.root update-openvas-plugins.sh

Then add to root’s crontab:

crontab -e

and add the following line:

0 3 * * 6 /bin/sh /scripts/update-openvas-plugins.sh

where this one runs weekly on Saturday at 3am. For more info on editing crontab see here.

Snort Plugin Update Script

Here’s the script to update snort:

#!/bin/sh
perl /usr/share/ossim/scripts/create_sidmap.pl /etc/snort/rules/
/etc/init.d/ossim-server restart

If the box is just a snort collector and doesn’t have the ossim-server running you’ll want to change that last line to read:

/etc/init.d/snort restart

or

/etc/init.d/snort_eth1 restart

Where eth1 is the interface snort is attached to.

Then edit crontab again and add in the line:

0 4 * * 6 /bin/sh /scripts/update-snort-rules.sh

This one runs every Saturday at 4am.

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Snare plugin not working on AlienVault OSSIM

Alienvault OSSIM is a great open-source product but I recently struggled to get my Snare logs to show up in the Security Events (SIEM) viewer.

First of all follow the steps in the Snare setup guide.

Now that you’ve setup snare and enabled the plugin you should see the plugin running when you go to Configuration -> Collection -> Sensors -> Click on the SIEM host. The SnareWindows plugin should show up as ENABLED and UP.

Check the Security Events for snare logs. They should look like:

Snare: A service was successfully sent a start/stop control

If you don’t see any then try this:

1. SSH to the server

2. As root type

vi /etc/ossim/agent/plugins/snare.cfg

3. Find the line that says:

location=/var/log/snare.log

4. Comment it out by putting a # at the start of the line so it looks like this:

#location=/var/log/snare.log

5. Now copy and paste the line and change the snare.log part to say messages so it looks like this:

#location=/var/log/snare.log
location=/var/log/messages

6. Restart the ossim-agent

/etc/init.d/ossim-agent restart

Now go back and check your Security Events view. If your problem was the same as mine then your snare logs should now start appearing.

Update

Perhaps the best way to reduce the CPU load caused by the agent parsing is to split the syslogs into separate log files using rsyslog. It needs a bit of planning in advance. Configure your snare installs to send their syslog messages to a particular facility, e.g. Local3. You can then setup rsyslog to split these into a new snare log.

Edit /etc/rsyslog.conf and scroll to the bottom and add in something like:

#Windows logs
if $syslogfacility-text == 'local3' then /var/log/snare.log

and restart the rsyslogd (/etc/init.d/rsyslog restart). Tail the /var/log/snare.log file to see if the logs are coming into the file correctly.

Now edit /etc/ossim/agent/plugins/snare.cfg and change the location line to point to this new log file:

location=/var/log/snare.log

Now edit the agent configuration file to include the plugin (/etc/ossim/agent/config.cfg). Scroll to the [plugins] section and check if the snare.cfg is listed. If it isn’t add it in:

snare-monitor=/etc/ossim/agent/plugins/snare.cfg

now restart the agent service

/etc/init.d/ossim-agent restart

and check back in the GUI.

If you still get nothing in the GUI it could be that the logs that are coming into the log file don’t match ┬áthe regex’s in the snare.cfg. To test this take a small sample of your logs and create a test log file, e.g tail -100 /var/log/snare.log > /var/log/snare-test.log. Now use the following to test the regex’s:

/usr/share/ossim/scripts/regexp.py /var/log/snare-test.log /etc/ossim/agent/plugins/snare.cfg q

You should see some lines being matched.

Some logs to check for errors:

/var/log/ossim/agent.log
/var/log/ossim/server.log

 

 

 

 

 

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