According to the American Cybersecurity & Infrastructure Security Agency (CISA), over 90% of successful cyberattacks start with email.1 Just one malicious link or attachment is often all it takes to cause data loss, financial damage, and lasting reputational harm. And with an estimated 160 billion spam emails sent to inboxes every day 2, every business should have a robust spam filtering strategy in place.
Email spam filtering keeps your business safe from malicious cyber schemes by preventing them from reaching your inbox in the first place. In this guide, we explain how email spam filtering works, why it matters, and share tips for staying vigilant against common threats.
What Is Email Spam Filtering?
Email spam filters are a type of software program that automatically detects and blocks unwanted messages, keeping your inbox safer and more secure. By stopping malicious emails at the source, spam filters lower the chance of employees interacting with dangerous links or attachments that could expose your business to cybercriminals.
Email is one of the top tools for daily communication at work. 52.2% of employees use it at least once a week, according to Email Tool Tester’s 2025 workplace communication survey.3 Unfortunately, cybercriminals send emails just as frequently as we do, if not more.
A separate Email Tool Tester survey found that 96.8% of participants have received spam messages in some form.2 Clicking on just one bad link or attachment can turn these emails into a gateway for bad actors to access your network.
In 2023, Barracuda surveyed 1,350 different IT decision makers and found that 75% of organizations dealt with a successful email attack in 2022 alone.4 Fortunately, thanks to advanced email filtering technology, there are ways to prevent spam emails from reaching your inbox in the first place.
Types of Spam Email Threats
It’s important to understand the types of spam email threats that are out there. With messages ranging from annoying junk mail to dangerous phishing schemes or malware, being able to identify common threats is essential for keeping your business secure.
Below are some of the top email spam threats that businesses face, including malware, common tactics, and specific types of attack emails.
Malicious Software (Malware)
Malware is short for malicious software. It’s designed to cause damage, disrupt systems, or gain unauthorized access to networks and devices. It’s one of the most common tactics that cybercriminals use to steal sensitive data and extort money from unsuspecting businesses.
Many email attacks include links and attachments that trick people into accidentally downloading malware onto their devices. This can put entire organizations at risk.
There are many different types of malware, including:
- Ransomware: encrypts files or entire systems and demands a ransom payment to restore access
- Viruses: injects malicious code into legitimate “host” files or programs and spreads when they are opened
- Worms: malicious programs spread through networks on their own by self-replicating
- Trojan horses: malware disguised as safe software that secretly installs harmful programs
- Spyware: runs in the background to collect passwords, browsing history, and other private data
Even if malware starts with one email, the damage can quickly spread across entire networks, causing data breaches, costly downtime, and financial setbacks.
Business Email Compromise (BEC)
Business email compromise (BEC) is a type of cyberattack where a criminal impersonates a trusted person, like a company executive or CEO, to trick employees into sending them money or sensitive data. This is a form of social engineering.
Unlike other email attacks, BEC doesn’t usually involve malicious links, attachments, or malware. Instead, scammers often rely on creating a sense of urgency or pressure to manipulate employees to make quick decisions that can be highly financially damaging.
Email Spoofing
Email spoofing is when a cybercriminal forges the sender address of an email to make it look like someone you trust, like a coworker, vendor, or even the CEO. The goal is to get the recipient to take an action they normally wouldn’t, such as clicking a malicious link, downloading malware, or sharing sensitive information.
Spoofing is not a type of malicious email, but the technical act of disguising the sender’s identity to bypass suspicion. For example, a BEC email can be spoofed to make the message appear as if it were sent from a trusted source.
Phishing Attacks
Phishing is a type of cybercrime that uses email, text, or phone calls to spread malware, extort money, or trick people into revealing sensitive information. According to the FBI, 300,479 successful phishing attacks were reported in 2022.5
There are multiple types of phishing scams, including standard phishing, spear phishing, and clone phishing. Each type can involve email spoofing or BEC.
Standard Phishing
Standard phishing emails are usually sent in bulk to lots of people so that statistically, at least a small fraction of them will take the bait. Phishing emails can use tactics like spoofing, malicious links that download malware, or manipulation tactics to extort sensitive information like passwords or credit card numbers.
Spear Phishing
Unlike standard phishing, which is usually much broader, spear phishing is a focused attack that targets specific individuals or organizations. These emails are highly personalized, making them more convincing and harder to detect than generic phishing emails.
For example, between 2013 and 2015, one scammer orchestrated an email scam that stole over $100 million from Google and Facebook, according to the U.S. Attorney’s Office.6 This is a spear phishing attack that falls under the BEC category.
It’s also an example of whaling, which is a more sophisticated type of spear phishing that targets high-profile victims, or “whales.”
Clone Phishing
Clone phishing is a type of cyberattack where scammers create a nearly identical copy of a legitimate email someone has previously received.
Even if it looks exactly like the original, clone emails substitute links or attachments to trick the recipient into downloading malware or providing sensitive information like banking information or passwords. These messages are often spoofed with forged email addresses to seem even more trustworthy.
For example, you might receive a clone email that looks like a normal shipping update, but the tracking link leads to a malicious site designed to steal your information.
How Does Email Spam Filtering Work?
Spam filtering uses advanced software to classify emails as safe or risky. If an email is deemed safe, it’s delivered to your inbox without interference. If the software detects a malicious email, that message is moved to the spam or junk folder, or blocked before it ever reaches your inbox.
At True IT, SpamTitan is our filter of choice. This award-winning software has a catch rate of 99.99%, making it highly effective for keeping business email inboxes spam-free.7
Below is an overview of how it works:
- Backlist checks: incoming emails are compared against lists of known spam sources to block obvious threats.
- Sender Verification (SPF & SMTP Controls): validates that the sender is authorized to use the email domain and that the message complies with proper server protocols.
- Spam Confidence Score (SCS): each email is given a score based on content analysis. This score determines whether the email is delivered, quarantined, or deleted (according to the recipient’s Acceptable Spam Threshold).
- Bayesian analysis: evaluates email wording and structure to detect unusual patterns or disguised terms (like using special characters to mimic letters).
- Greylisting: temporarily rejects emails and asks the sender’s server to resend them. Legitimate servers comply, but spam servers don’t, so this reduces the amount of spam that slips through.
Together, these layered defenses create a powerful filtering system that keeps your inbox secure, organized, and free from harmful or unwanted messages.
Benefits of Email Spam Filtering for Businesses
A strong spam filter is the first line of defense between your organization and malicious emails. By automatically identifying and blocking suspicious messages, spam filtering helps save time, boost productivity, and reduce the risk of dangerous phishing attacks for businesses big and small.
Some of the top benefits of email spam filtering for businesses include:
- Enhances security: block up to 99.99% of spam emails to avoid phishing attempts, malware, and other cyberthreats before they reach your team.7
- Increases productivity: with less junk mail to sort through, employees can save time and focus on tasks that matter most.
- Improves communication: critical emails can easily go unnoticed if your team’s inboxes are constantly flooded with spam. Spam filtering clears the noise to make sure nothing important gets lost.
- Saves money: every lost minute of time adds up to lost money, with the average cost of managing spam per person at about $285.7 Spam filtering means less wasted time clearing inboxes and overanalyzing every email for risks.
- Improves email performance: email filtering reduces strain on servers by preventing large volumes of spam from being processed or stored.
- Customizable control: advanced filtering software lets you fine-tune spam thresholds, manage quarantines, and whitelist trusted senders.
With a reliable spam filter in place, businesses can enjoy a safer, more efficient email environment that keeps your organization secure.
Protect Your Business with Email Spam Filtering
Email spam filtering is one of the most reliable ways to protect your business from dangerous cyberattacks. By using advanced software and algorithms, it blocks spam and phishing attempts from reaching inboxes in the first place—keeping your team more productive and secure.
At True IT, we have years of experience providing managed IT services to Sonoma County businesses of all sizes. By combining advanced spam filtering software with ongoing monitoring, our experts work behind the scenes to keep your organization safe while you focus on core business goals.
Don’t wait for a cyberattack to harm your business. Contact us online today or call (707)-755-5858 to claim your FREE IT consultation.
References
- Shields Up: Guidance for Families. (n.d.). Cybersecurity and Infrastructure Security Agency (CISA). https://www.cisa.gov/shields-guidance-families
- Ellis, C. (2024b, October 16). Spam Statistics 2025: New data on junk email, AI scams & Phishing. EmailTooltester.com. https://www.emailtooltester.com/en/blog/spam-statistics/
- Phillips, R. (2024, March 1). Workplace Communication Statistics: Fresh data for 2025. EmailTooltester.com. https://www.emailtooltester.com/en/blog/workplace-communication-statistics/
- Barracuda. (2023). 2023 EMAIL SECURITY TRENDS. https://assets.barracuda.com/assets/docs/dms/2023-email-security-trends.pdf
- Federal Bureau of Investigation. (n.d.). 2022 Internet Crime Report. https://www.ic3.gov/Media/PDF/AnnualReport/2022_IC3Report.pdf
- Lithuanian man pleads guilty to wire fraud for theft of over $100 million. (2019, March 20). https://www.justice.gov/usao-sdny/pr/lithuanian-man-pleads-guilty-wire-fraud-theft-over-100-million-fraudulent-business
- Choose the best Spam Filtering Service. (2025, July 1). SpamTitan Email Security. https://www.spamtitan.com/spam-filtering-service/
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