How To Use the Email Collector

This How To is intended to help you configure, use and test the Email Collector in your existing NetEye Tornado installation. We will configure a new rule to log all incoming mail subject lines in one file for each from email address.

Step #1: Email and Package Configuration

• For testing purposes, we will use mailx to locally send email messages to the eventgw mailbox on NetEye via postfix. In a production environment, you or your Administrator will need to configure the mail infrastructure such that the eventgw mailbox on NetEye is integrated into your company’s mail infrastructure.

• If you’ve just upgraded your Tornado installation, run neteye-secure-install, then make sure the Email Collector service is running:

  # systemctl status tornado_email_collector.service
  ● tornado_email_collector.service - Tornado Email Collector - Data Collector for procmail
  Loaded: loaded (/usr/lib/systemd/system/tornado_email_collector.service; disabled; vendor preset: disabled)
  Drop-In: /etc/systemd/system/tornado_email_collector.service.d
         └─neteye.conf
  Active: active (running) since Thu 2019-06-20 19:08:53 CEST; 20h ago
  

• Send an email to the dedicated eventgw user which will then be processed by Tornado: # echo "TestContent" | mail -s TestSubject eventgw@localhost

• Now test that an email sent to that address makes it to Tornado (the timestamp reported by journalctl should be at most a second or two after you send the email):

  # journalctl -u tornado_email_collector.service
  Jun 21 15:11:59 host.example.com tornado_email_collector[12240]: [2019-06-21][15:11:59]
  [tornado_common::actors::uds_server][INFO] UdsServerActor - new client connected to [/var/run/tornado/email.sock]``
  

Step #2: Service and Rule Configuration

Now let’s configure a simple rule that just archives the subject and sender of an email into a log file.

Here’s an example of an Event created by the Email Collector:

{
  "type": "email",
  "created_ms": 1554130814854,
  "payload": {
    "date": 1475417182,
    "subject": "TestSubject",
    "to": "email1@example.com",
    "from": "email2@example.com",
    "cc": "",
    "body": "TestContent",
    "attachments": []
  }
}

Our rule needs to match incoming events of type email, and when one matches, extract the subject field and the from field (sender) from the payload object. Rules used when Tornado is running are found in /neteye/shared/tornado/conf/rules.d/, but we’ll model our rule based on one of the example rules found here:

/usr/lib64/tornado/examples/rules/

Since we want to match any email event, let’s adapt the matching part of the rule found in /usr/lib64/tornado/examples/rules/001_all_emails.json. And since we want to run the archive executor, let’s adapt the action part of the rule found in /usr/lib64/tornado/examples/rules/010_archive_all.json.

Here’s our new rule containing both parts:

{
    "name": "all_email_messages",
    "description": "This matches all email messages, extracting sender and subject",
    "continue": true,
    "active": true,
    "constraint": {
      "WHERE": {
        "type": "AND",
        "operators": [
          {
            "type": "equal",
            "first": "${event.type}",
            "second": "email"
          }
        ]
      },
      "WITH": {}
    },
    "actions": [
      {
        "id": "archive",
        "payload": {
          "sender": "${event.payload.from}",
          "subject": "${event.payload.subject}",
          "event": "${event}",
          "archive_type": "archive_mail"
        }
      }
    ]
}

Changing the “second” field of the WHERE constraint as above will cause the rule to match with any email event. In the “actions” section, we add the “sender” field which will extract the “from” field in the email, the “subject” field to extract the subject, and change the archive type to “archive_mail”. We’ll see why in Step #3.

Remember to save our new rule where Tornado will look for active rules, which in the default configuration is /neteye/shared/tornado/conf/rules.d/. Let’s give it a name like 030_mail_to_archive.json.

Also remember that whenever you create a new rule and save the file in that directory, you will need to restart the Tornado service. And it’s always helpful to run a check first to make sure there are no syntactic errors in your new rule:

# tornado --config-dir=/neteye/shared/tornado/conf check
# systemctl restart tornado.service

Step #3: Configure the Archive Executor

If you look at the file /neteye/shared/tornado/conf/archive_executor.toml, which is the configuration file for the Archive Executor, you will see that the default base archive path is set to /neteye/shared/tornado/data/archive/. Let’s keep the first part, but under “[paths]” let’s add a specific directory (relative to the base directory given for “base_path”). This will use the keyword “archive_mail”, which matches the value of the “archive_type” field in the “action” part of our rule from Section #3, and will include our “source” field, which extracted the source IP from the original event’s payload:

base_path =  "/neteye/shared/tornado/data/archive/"
default_path = "/default/default.log"
file_cache_size = 10
file_cache_ttl_secs = 1

[paths]
"archive_mail" = "/email/${sender}/extracted.log"

Combining the base and specific paths yields the full path where the log file will be saved (automatically creating directories if necessary), with our “source” variable instantiated. So if the sender was email2@example.com, the log file’s name will be:

/neteye/shared/tornado/data/archive/email/email2/extracted.log

When an SNMP event is received, the field “event” under “payload” will be written into that file. Since we have only specified “event”, the entire event will be saved to the log file.

Step #4: Check the Resulting Email Match

Let’s see how our newly configured Email Collector works using a bash shell.

First we will again manually send an email to be intercepted by Tornado like this:

# echo "The email body." | mail -s "Test Subject" eventgw@localhost

Event processing should be almost immediate, so right away you can check the result of the match by looking at the log file configured by the Archive executor. There you should see the sender and subject written into the file as we specified during Step #3:

# less /neteye/shared/tornado/data/archive/email/eventgw/extracted.log

And that’s it! You’ve successfully configured Tornado to process emails and logging the subject and sender to a dynamic directory per sender.