Teach your Inbox to Recognize Spam

MDaemon has many features for fighting spam that, when configured properly, can be very effective at blocking out unwanted junk email.  However, it is possible for the occasional spam message to slip through. Likewise, it is also possible for the occasional non-spam message to be mistakenly identified as spam and blocked from being delivered. This is especially true if you work in finance or the medical industry, where you are more likely to receive legitimate email messages that contain words often found in spam. This presents a challenge: How can administrators and end users improve the accuracy of the spam filter?

An effective solution to the problem is using Bayesian analysis to help MDaemon “learn” what is & is not spam.

You may be thinking, “So what is Bayesian analysis?” Bayesian analysis is based on Bayesian logic, which is a branch of logic that deals with probability inference – predicting future events based on knowledge of prior events. In the context of spam filtering, MDaemon’s Bayesian Learning feature uses Bayesian logic to make inferences about the probability that a message is spam based on the patterns contained within it and how those patterns compare with the patterns found in messages that have been fed to the Bayesian Learning engine.

Bayesian Learning helps train MDaemon’s spam filter to become more accurate over time by feeding it samples of spam and non-spam messages. This is especially useful for the medical and finance industries, where certain keywords are “spammy” to one industry but not the other. This feature also helps reduce false positives (legitimate messages mistakenly marked as spam) or false negatives (spam messages that were not marked as spam).

So how does Bayesian Learning work & how can users use it to train their inboxes to recognize spam? Keep reading to find out!

How to Use Bayesian Learning – The Short Version

Before we get into the details of how to use MDaemon’s Bayesian Learning features, let’s start with a high-level overview of how to use it. First, the administrator enables Bayesian Learning in MDaemon. Then, the administrator creates the Spam and Non-Spam public folders and grants users Lookup/Insert access rights to those folders. Ham/Spam forwarding addresses can also be enabled, so that messages sent to them as attachments can be fed to the Bayesian Learning engine accordingly. Users who receive false-negatives or false-positives can then feed those messages to the Bayesian Learning engine using various methods. By default, after 200 spam and non-spam messages have been collected, Bayesian Learning takes place & the contents of these messages are added to a database of “tokens.”

Instructions for Administrators

The administrator needs to enable Bayesian Learning in MDaemon, and configure Bayes folder access and optionally configure forwarding addresses, as outlined in the following steps.

  1.  In MDaemon, navigate to Security | Spam Filter, and click on Bayesian Classification in the left-hand navigation menu.

    MDaemon Bayesian Learning
    Bayesian Learning in MDaemon
  2. Check the first box to enable Bayesian classification.
  3. By default, the second box (Schedule Bayesian learning for midnight each night) is checked. If you have a lot of spam/non-spam messages to learn from, you may want to schedule Bayesian learning at more frequent intervals by un-checking this box and entering a value in the following blank (Schedule Bayesian learning once every __ hours).
  4. Most spam messages are relatively small, so to improve performance, you can enter a value in the “Do not learn from messages larger than” blank. 50,000 bytes is the default value.
  5. Before we discuss the checkbox to enable spam/ham forwarding addresses, we need to create public folders for spam and non-spam messages. Click on the Create button to populate these fields with the default location for these folders, or use the buttons to the right to specify a different location. By default, access permission to these folders is only granted to local users of local domains and is limited to Lookup and Insert rights. The postmaster’s default permissions are Lookup, Read, Insert, and Delete. To prevent users from placing spam in the non-spam folder and vice-versa, you could remove access to these folders for all users except the administrator (via Setup | Public Folder Manager), and create another pair of spam/non-spam folders, then grant users Lookup and Insert rights to those folders instead. This allows the administrator to review the contents of these folders for improperly placed messages before placing them in the Bayesian Spam and Non-Spam folders.
  6. You can optionally check the box “Enable spam and ham forwarding addresses.” When this box is checked, users can forward false-negatives or false-positives to spamlearn@yourdomain.com or hamlearn@yourdomain.com to feed these messages to the Bayesian Learning engine. This process is explained in greater detail later in this post.
  7. Users who have been granted Lookup & Insert access rights to the Spam and Non-Spam folders can use the thumbs-up & thumbs-down icons in WorldClient to feed spam (false-negatives) and non-spam (false-positives) to the Bayesian Learning engine. Administrators who wish to remove these icons for all users can edit the MDaemon/WorldClient/Domains.ini file and add the following:
    [Default:UserDefaults]
    DisableSpamButton=Yes
    DisableHamButton=Yes 
    Save the file and restart MDaemon (or IIS, if WorldClient is running on IIS).
  8. Administrators who wish to remove these icons for a specific user can edit the User.ini file for the user (located at MDaemon/Users/example.com/(username)/WC) as follows:
    [User]
    DisableSpamButton=Yes
    DisableHamButton=Yes

Instructions for End Users

Now that Bayesian Learning is properly configured in MDaemon, users can begin feeding the Bayesian Learning engine samples of spam and non-spam messages to train the spam filter to become more accurate. There are various ways to train the Bayesian Learning engine – using the thumbs-up & thumbs-down icons in WorldClient, using drag & drop to drag messages to the Spam and Non-spam folders (when using IMAP or Outlook Connector), or forwarding messages as attachments to the assigned spamlearn@ or hamlearn@ addresses (useful for POP users).

Using WorldClient

The easiest way to train the Bayesian Learning engine is to select “This is Spam” or “This is Not Spam” (in the WorldClient theme) or the thumbs-up and thumbs-down buttons (in the LookOut and WorldClient themes) in WorldClient. Simply click once on it to highlight it, and then select “This is Spam” or click on the thumbs-down icon. If a legitimate, non-spam message was placed in your Spam folder, you can highlight it, and then select “This is Not Spam” or click on the thumbs-up icon.

Mark as Non-Spam
Mark as Non-Spam

Using Drag & Drop (IMAP & Outlook Connector)

IMAP and Outlook Connector users who have been granted Lookup and Insert access rights to the spam and non-spam folders can use drag & drop to move the message to the appropriate spam/non-spam folder.

Forwarding as Attachments (POP3)

POP3 users can forward these messages (as an attachment from an authenticated session) to the spamlearn@ and hamlearn@ addresses. Messages sent to these addresses must be received via SMTP from a session that is authenticated using SMTP AUTH.

Considerations

As explained under step 5 above (under Administrator Instructions), when granting users access to the Bayesian Spam and Non-Spam public folders, it’s possible for users to feed samples of spam and non-spam to the wrong folders, making the Bayesian learning process less effective, thus, you may consider creating a separate pair of Spam/Non-Spam public folders and having users place messages in those folders instead for administrative review.

Conclusion

When used properly, Bayesian Learning is a powerful tool for reducing spam and ensuring legitimate messages are not blocked by the spam filter. More information can be found in the following knowledge base articles:

Bayesian Learning Information:
http://www.altn.com/Support/KnowledgeBase/KnowledgeBaseResults/?Number=227

Training the Bayesian Learning Process in MDaemon:
http://www.altn.com/Support/KnowledgeBase/KnowledgeBaseResults/?Number=378

Bayesian Learning Tips & Tricks:
http://www.altn.com/Support/KnowledgeBase/KnowledgeBaseResults/?Number=379

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Are you taking the security of your email account seriously?

WEmail Securitye begin a series of posts on the importance of email security and why it should be a top priority for organizations. In this post, we share some insights from the founder of Alt-N Technologies, Arvel Hathcock, to get his perspective on security tips for email users.

Most everyone has an email account. Many have more than one. Email is really at the core of online life because it is tied to so many of our online services. Look at your phone. Many of the service apps you see connect with you via your email account. This is why I believe the wide-spread practice of “password reset via email message” or “Forgotten Password” has crowned the email account password the most significant and important of all passwords.

Password Controls in MDaemon
Password Settings in MDaemon

That’s not to say that password management for services like online banking are not critical. They are. But having a strong password for banking and not your email can expose you to some real dangers, as well.   Imagine if a hacker or other bad actor can figure out your email password. One of the first actions they could take is to login and change your password. This locks you out. Next, they check through your inbox and folders looking for anything interesting, such as popular online services or banking portals. Now, they login with your email address and use the “Forgotten Password” feature. Soon an email will show up in your inbox (which is no longer controlled by you) allowing them to verify the change and now another important service is not controlled by you. This email and others like it will allow a hacker to change all of your online passwords – all because they found your email password.

This is not good and it leads me to security tip #1: Put effort into the security of your email account password.

It can be the key to all your other passwords. Also, do not use your email account password with any other online account or service because you do not know and cannot control when it will be that service’s turn to get hacked.

Because of the risk mentioned earlier, I would also recommend users disable “Forgotten Password” features where possible and use an alternative method. As bad as “Forgotten Password” can be to reset access, the Question and Answer options can be risky, too. I was horrified years ago to discover that an online app for a banking chain reset my password using only the “Question and Answer” method – no email at all! You know – the questions some services ask like “What’s your mom’s name?” or “Where did you grow up?” etc. If someone can get the answers right, they can change the password.

This idea assumes that would-be hackers will always be outsiders without access to even basic information about their targets. You should use caution before completely trusting these methods. One trick I recommend is to select the question (it’s usually in a drop-down list) and enter a totally random and completely unpredictable answer (but one that you can remember, of course).

I realize these features exist for convenience but remember that security can be reduced and new attack options exposed by these methods if not managed properly.

 

 

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MDaemon 16.5 – with Automatic Updates, WorldClient Categories & More!

Earlier this year, we introduced several new security and convenience features for MDaemon, including contact synchronization via CardDAV, two-factor authentication in WorldClient, spambot detection, and an ActiveSync migration client for migrating from any mail platform that supports ActiveSync protocol version 14.1. If you’re running an older version of MDaemon and would like to see what you may be missing, check out our MDaemon Features by Version page for all features by release version.

For MDaemon 16.5, we continue the trend of packing in new features for both administrators and end users.

Administrators will Benefit From these New Features:

Centralized Management of Outlook Users

Outlook Connector Client Settings

Outlook Connector allows Outlook users to share their email, calendars, contacts, tasks and notes. In previous versions of MDaemon and Outlook Connector, users would configure all settings on the Outlook Connector client, including host names, SSL and port settings, and other preferences. Beginning with MDaemon 16.5 and Outlook Connector 4.0 (also released today), these settings can now be stored centrally in MDaemon and pushed out to clients. When a new Outlook Connector profile is created, only the username and password are needed. All other settings are retrieved from MDaemon with the click of a button.

Unique Public Key Management for Encryption Security Control

OpenPGP Encryption Settings

OpenPGP uses public/private key pairs to encrypt and decrypt messages. If I want to send you an encrypted message, I would need to obtain your public key, which is used to encrypt the message, and you would decrypt it with your private key. WorldClient, MDaemon’s webmail client, can now be used as a basic public key server for exchanging public encryption keys. This allows WorldClient to honor requests for your users’ public keys using a specially formatted URL. Additionally, MDaemon’s OpenPGP feature now supports collection of public keys over DNS. This helps to automate the process of exchanging encryption keys.

Automatic Product Updates

Automatic Updates
Automatic Updates

It’s easier to ensure that you’re running the latest version of MDaemon, Outlook Connector, and SecurityPlus with the new Automatic Updates feature. Updates can be automatically downloaded and installed at a designated time.

For end users, we’ve added these new features:

Easily Identify Trusted Email & Confirm Message Authenticity to Prevent Spearphishing

 

DKIM Verified Sender
DKIM Verified Sender

MDaemon’s OpenPGP features can now verify embedded signatures found within messages. This helps the recipient ensure that the message is authentic. WorldClient will display an icon or text label for verified messages. WorldClient will also display labels for messages with valid DKIM signatures, messages decrypted by OpenPGP, and messages signed with an OpenPGP key.

WorldClient Categories for Easier Inbox Management

WorldClient Message Categories
WorldClient Message Categories

When using the LookOut and WorldClient themes, WorldClient has new category selections for easy sorting and identification of email messages. Messages can be sorted by category, and multiple categories can be assigned to a message. Authorized users can also create their own custom categories in addition to using the built-in categories.

Connect with most IM Clients

XMPP Chat Server
XMPP Chat Server

MDaemon 16.5 includes two separate chat systems. In addition to WorldClient Instant Messenger, users can now chat with each other using their favorite third-party chat (XMPP) client. With the addition of this feature, users now have the flexibility to chat from any device with a compatible XMPP client, including mobile devices.

There are many XMPP clients to choose from, including Trillian (Windows), Adium (Mac OSX), and Mozilla Thunderbird (Linux, OSX, Windows). A list of XMPP clients can be found here: http://xmpp.org/software/clients.htm.

Features may vary depending on which XMPP client is used. WorldClient Instant Messenger’s features can be found here:

http://www.altn.com/Products/MDaemon-Email-Server-Windows/WorldClient-Instant-Messenger/

Other improvements include:

Additional SMTP authentication settings

SMTP Authentication from Local IPs
SMTP Authentication from Local IPs

The SMTP Authentication screen has a new option which, when enabled, will require all incoming messages from local IP addresses to use SMTP authentication. When this setting is enabled, if a message that is not authenticated arrives from a local IP address, it will be rejected. We recommend enabling this setting for added security.

Modification of “From” header as additional protection from spoofing

Sometimes users are fooled into thinking an email comes from one person when it is actually from an attacker. This happens because email clients often display only the sender’s name and not his email address. This new option defeats such an attack  by altering the From: header value. If enabled, when a message arrives for a local user, its From: header is modified. For example: From: “Spartacus” <crixus@capua.com> would become From: “crixus@capua.com — Spartacus” <crixus@capua.com>.

WorldClient can check for attachments if they are mentioned in the subject/body.

WorldClient Attachment Notification
WorldClient Attachment Notification

When an attachment is mentioned in the subject or body of a message, yet no file is attached, WorldClient can be configured to remind the sender of a possibly missing attachment when clicking the Send button.

These are just the major new features for MDaemon 16.5. For a complete list of all new features & enhancements, view the MDaemon release notes. Or if you’re ready to try MDaemon for free, click here to download your free trial!

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