Email alerts are sent hourly

[Alexis Lessard]

Hi!

We are trying to configure more effective notifications for OSSEC for our needs. However, something weird is happening. An hourly report of ALL alerts is being sent to one adress in our config. Here's the email configuration of our ossec.conf file:

 <global>

    <email_notification>yes</email_notification>

    <email_to>noreply@localhost</email_to>

    <smtp_server>smtpserver</smtp_server>

    <email_from>os...@domain.com</email_from>

  </global>

  <email_alerts>

    <email_to>email1</email_to>

    <email_to>email2</email_to>

    <email_to>email3</email_to>

    <event_location>several, agents, name</event_location>

  </email_alerts>

  <email_alerts>

    <email_to>our...@domain.com</email_to>

    <level>9</level>

  </email_alerts>

  <email_alerts>

    <email_to>email4</email_to>

    <level>10</level>

    <do_not_delay />

    <do_not_group />

  </email_alerts>

  <email_alerts>

    <email_to>our...@domain.com</email_to>

    <level>6</level>

    <group>attack</group>

  </email_alerts>

  <email_alerts>

    <rule_id>10100</rule_id>

    <email_to>our...@domain.com</email_to>

  </email_alerts>

Basically, here's what I'd like OSSEC to do:

• Send an email for every level 9 or higher alert
• Send an email for every matchd rule from the attack group of level 6 or higher
• Send an email for the rule 10100 wich shows when a user is logged for the first time.
• The other rules are for user specific needs. 

I modified the email for this example, but in the file, they are your usual name@domain format. We send every alert to noreply@localhost because we want to control everything with custom alerts. The email_alert_level is set to 0, so every alert is supposed to be sent to this adress. But no alert of a level 3 should be sent to our email box, right? Yet we receive every alerts at the same time (in the same email) every hour, It is being sent at the our...@domain.com as well as email4 . Am I doing something wrong here? Can OSSEC behave the way I want it to do?

Thanks for the help!

[Jesus Linares]

Hi Alexis,

I'm not sure about what it is happening. Do a simple test. Set email_alert_level to 1, and configure only one custom alert:

<global>
    <email_notification>yes</email_notification>
    <email_to>noreply@localhost</email_to>
    <smtp_server>smtpserver</smtp_server>

    <email_from>email1</email_from>
  </global>


  <email_alerts>
    <email_to>email2</email_to>

    <level>10</level>
    <do_not_delay />
    <do_not_group />
  </email_alerts>

Generate an alert with level 10, you will receive:

• all alerts in email1 (including alerts with level 10)
• alerts with level 10 in email2
  

That is the theory.

I hope it helps.

Regards.

[Alexis Lessard]

Thanks for the tip! We tested it, but it doesn't seem to be working. Here's what the configuration looks like now:

  <global>

    <email_notification>yes</email_notification>

    <email_to>noreply@localhost</email_to>

    <smtp_server>smtpserver</smtp_server>

    <email_from>ossec@domain</email_from>

  </global>

  <email_alerts>

    <email_to>email1</email_to>

    <email_to>email2</email_to>

    <email_to>email3</email_to>

    <event_location>several, agents, name</event_location>

  </email_alerts>

  <email_alerts>

    <email_to>ourservice@domain</email_to>

    <level>9</level>

    <do_not_delay />

    <do_not_group />

  </email_alerts>

email_alert_level was also set to 1. We received one level 10 alert email by itself. However, there were several others level 10 alerts that we didn't receive any notifications from, even tough they appear in the alert log. We then received an email report in ourservice@domain mailbox of about 10 minutes worth of  events, with several level 10 alerts in it, but mostly a lot of alerts we have no need for, like
Rule: 31101 fired (level 5) -> "Web server 400 error code." 

I don't think that there's anything in my config that would justify alerts of level 3 and 5 being sent. Do you know what could be wrong? We will probably go back to having an email_alert_level of 7 with no custom alerts and work from there. We receive a lot of events to this server; I'd say about one every two or three seconds. Could that be a problem?

Thanks you for the reply, I'll be sure to keep you updated to document the issue if anyone else has that problem,

[Jesus Linares]

Hi Alexis,

So, you are receiving alert with level 3 in ourservice@domain, right?. That doesn't make sense (I understand that email1, email2 or email3 is not ourservice@domain).

Try to use: do_not_delay and do_not_group. Also, the email_maxperhour is 12 by default, maybe you should change it.

In order to simplify the debug process, use only 1 custom email alert.

Also, you can use the report settings instead of the email settings.

OSSEC emails options aren't that good...

[Alexis Lessard]

The issue was indeed the email_maxperhour setting. My guess is, because we basically told OSSEC to send every event to noreply@localhost. The default threshold was reached pretty quickly, so all events until the threshold was reach until the end of the hour were sent back to us in a big email. We changed that setting to its maximum value, 9999, and now we receive all alerte we specified we wanted (altough now we might have some tweaking to do in our local_rules to adjust it to our needs), but at least, it works!

tl;dr: Ensure that the email_maxperhour setting in the global config is set to an appropriate value. Default is 12.

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[Jesus Linares]

Finally, you got it!.

I think your conclusion makes sense.

Regards.

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