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What is an Email Spam Filter?

The majority of email service providers employ anti-spam mechanisms to filter incoming emails; although without a third-party incoming email spam filter spam emails will still be delivered to end users’ inboxes. The volume of spam emails that make it past proprietary spam detection systems can be considerable.

Spam email is a major drain on productivity even when spam email volume is relatively low. Studies on productivity losses from email spam show an average medium-sized organization with 500 staff members who receive just 6 spam email messages a day is likely to lose more than 130 man-hours every year dealing with those messages.

Lost productivity is not the only problem. The majority of spam emails are malicious and are used to ‘phish’ for sensitive information or infect computers with malware or ransomware. The cost of phishing and resolving malware infections is considerable. According to a 2015 Ponemon Institute report – “The Cost of Phishing & Value of Employee Training” – an average organization will be forced to spend $1.8 million every year on malware removal and data recovery.

Malware infections can occur in an instant. All it takes is a single employee to open an infected email attachment for an organization’s network to be compromised. Blocking malicious spam emails using an incoming mail spam filter typically costs just $10 per end user, per year. It is a small price to pay to protect networks from malware and is considerably less than the cost of resolving malware infections.

Did You Know?


SpamTitan's spam catch rate

11 Seconds

a ransomware attack occurs


the average cost to manage spam per person without an email filter


of all email is spam

Why Use an Incoming Email Spam Filter? 

Most email services are not particularly effective at blocking spam because incoming emails are only subjected to basic checks for common spam signatures. Third-party email spam filters use a much greater range of techniques and mechanisms to determine whether emails are genuine and should be delivered.

Sender Policy Frameworks and SMTP controls are used along with a host of other front-end tests. Initially, incoming emails are checked against spam blacklists. If emails pass this initial check they are then subjected to deeper inspection using mechanisms such as Bayesian analyses and Greylisting.

Spammers are now becoming much better at crafting emails to fool basic email spam filters. For example, a spam email containing the word ‘Viagra’ may be caught by a basic spam filter. However, if the spammer substitutes the a’s for the Greek letter alpha – Viαgrα – this is enough to fool basic spam filters.

Third-party email spam filters use Bayesian analyses to check for these subtle changes and other idiosyncrasies that are used by spammers to bypass basic antispam filters.

After a Bayesian Analysis, an advanced incoming mail spam filter will pass the email on for another check: Greylisting. Greylisting is a technique that involves sending the email back to the sender’s mail server with a request to resend the email. Since spammers set their mail servers to send huge runs of spam emails, these requests to resend emails are usually treated as low priority. When the email is not resent within a certain time-frame, an advanced incoming mail spam filter will categorize the message as spam.

These two techniques ensure that new spam email campaigns that have not yet been blacklisted are still intercepted and quarantined. Standard email spam filters would not block these messages until they are added to spam blacklists.

“The Cost of Phishing & Value of Employee Training” – an average organization will be forced to spend $1.8 million every year on malware removal and data recovery."

Checking Incoming Emails for Viruses and Malware

Advanced email spam filters also check messages for the presence of malware. Antivirus software is not always particularly effective at blocking malicious email messages. Antivirus software may not even check email messages at all.

Antivirus software is also ineffective at identifying malicious links that are contained in spam email messages. Links to phishing websites or sites laced with malware can all too easily get past standard email spam filters, yet these emails are the most dangerous. If these emails are delivered, organizations must rely on end users to identify the links as malicious and not click on the links. Visiting those links can be all it takes to install malware on a network. Unfortunately, even if security awareness and anti-phishing training is provided, some employees will still click on these malicious links.

An advanced incoming mail spam filter will check each email for malicious links and attachments against a database of known threats, whereas this check is typically not performed by basic email spam filters. Further, an incoming mail spam filter will typically also perform checks of outgoing mail. If an employee inadvertently forwards an email that contains a malicious link or attachment, the email will also be quarantined. Checks on outgoing mail are important, not only to prevent the spread on an infection around an organization, but also to prevent the organization’s email server from being added to a spam blacklist.

Sandboxing greatly increases the detection rate of elusive threats in the pre-execution stage, including APTs, targeted attacks, evasion techniques, obfuscated malware, custom malware, and ransomware.

An average organization will be forced to spend $1.8 million every year on malware removal and data recovery.

Why Use SpamTitan as Your Incoming Email Spam Filter?

SpamTitan is a robust and highly effective incoming email spam filter that uses a range of mechanisms to check each incoming email for a host of spam signatures. SpamTitan uses both Greylisting and Bayesian Analyses to improve detection rates.

The multi-layered detection mechanisms ensure that more than 99.97% of spam emails are identified and quarantined, according to VB Bulletin – The leading, independent testing and certification organization. VB Bulletin also confirmed SpamTitan has an extremely low false positive rate: Just 0.03%.

SpamTitan uses not one, but two antivirus engines to check for malware in real-time with a 100% malware detection rate on both incoming and outgoing emails.

SpamTitan Cloud is a cloud-based antispam solution and is available with three different hosting options. This solution is better suited for large organizations and Managed Service Providers (MSPs). Both deployment options are highly scalable with no limits placed on the number of end users or domains.

Register Today for a 14-Day Free Trial of our Email Spam Filter

We believe you will be impressed with how effective our solution is at preventing the delivery of spam email, as well as how easy SpamTitan is to install, use, and manage.

We understand that most businesses would like to try our solution before agreeing to purchase a license to use the product. We therefore, offer SpamTitan on a 14-day, no obligation trial so you can evaluate our incoming mail spam filter in your own environment. The offer includes a fully-enabled incoming mail spam filter as well as technical and customer support.

Register for your free trial

You will have the opportunity to have your questions answered and you will be guided through the installation process. You will be able to protect your organization from malware and block spam emails in a matter of minutes. 

Susan Morrow

Susan Morrow


Talk to our Team today

Talk to our Team today