Top Email Security Threats in 2025

In 2025, email remains the #1 cybercrime entry point for attackers, and small businesses are prime targets. Nearly half of all cyberattacks in 2023 hit SMBs. Phishing emails routinely fool employees, and many small firms still rely only on free or built-in filters. This complacency can be costly: the average cyberattack costs an SMB about $250K, and 75% of SMBs say a ransomware hit could put them out of business. In short, email threats can inflict devastating financial and reputational damage. Below, we explain the top 6 email security threats expected in 2025 – and why default spam filters (Gmail/Microsoft 365, etc.) aren’t enough to stop them.

Business Email Compromise (BEC)

What it is: BEC attacks exploit trust by impersonating someone you know (a CEO, vendor, or colleague). Unlike obvious spam, these emails look legit – maybe a change-of-bank-details notice or an urgent invoice that appears to come from a familiar address. Attackers don’t need malware; they simply trick you into wiring funds or revealing sensitive data. For example, cybercriminals might spoof a vendor’s email and send a “fake purchase order” or pose as the CEO requesting an urgent wire transfer. They can even hijack real email accounts or ongoing threads, inserting themselves into conversations to appear more convincing.

Why it’s dangerous:  BEC is the costliest cybercrime. In 2023, U.S. losses from BEC hit $2.9 billion (Internet Crime Report). Globally, an estimated $6.7 billion was stolen via BEC last year​ – more than any other cyber-fraud type. SMBs feel this acutely: one report found the average business interruption from a successful BEC scam at an SMB was about $487,000. Even a single mistake (say, an accounts-payable clerk wiring money to a fraudster) can wipe out profits and shake customer trust. Because BEC emails contain no malicious code or obvious spam, they easily bypass normal filters. Without extra protection (and employee training), there’s often no warning before it’s too late.

Phishing and Spear Phishing Attacks

What they are:  Phishing attacks send deceptive emails that lure recipients into clicking a malicious link or entering login credentials. Spear phishing is a targeted form where attackers research your company or employees first, making the bait highly customized. For instance, attackers often imitate well-known brands – Microsoft, Apple, or Google – to trick victims with fake security alerts or login pages. In Q4 2024, Microsoft was spoofed in 32% of brand-related phishing campaigns, with Apple and Google around 12% each. Even familiar events (holiday sales, vendor invoices, shipping notices) can be phony. In fact, scammers frequently lure people with fake discount offers on popular brands like Nike or Adidas, harvesting login details when users submit them on bogus sites.

Why they’re dangerous:  Phishing is by far the most common way hackers breach SMBs. Industry data show that 80–95% of all cyber breaches start with a phishing email. As AI makes scam emails more convincing (even using employee names or company jargon), attackers have flooded inboxes. One study reports a 4,151% increase in phishing volume since AI tools like ChatGPT emerged. Phishing can deliver malware or steal credentials: for example, a single click on a malicious link might install ransomware. IBM’s 2024 breach report found that the average cost of a successful phishing-based breach is about $4.88 million, disastrous even for mid-size businesses. For SMBs, any breach can result in lost revenue, regulatory fines, or a ruined reputation. Since employees (especially without training) are the weakest link, and 68% of breaches involve human error, every phishing email is a critical threat.

Email Spoofing & Domain Impersonation

What it is:  Spoofing attacks involve forging the sender’s email address or using a “look-alike” domain name to trick recipients. For example, a scammer might register yourcompany.support@gmail.com or register a domain like contoso-inc[.]com (one letter off) that looks just like your supplier’s site or like your CEO: Body:

"Hi [Employee's Name],

*I’m currently in a meeting and can’t talk, but we have an urgent payment that needs to be processed today. Please transfer $48,500 to the vendor below for an outstanding invoice. This is time-sensitive, so treat it as a priority.*

Vendor Name: Example Global Tech Solutions

Bank: First National Bank

Account #: 1234567890

Routing #: 987654321

*Let me know once completed, and send me the confirmation. Reach out to me via text at (555) 123-4567 if there are any issues.*

Best regards,

John Smith

CEO, Company Name" When you see an email from that address, it appears to come from a trusted source. Attackers use this to harvest credentials on fake login pages or to sneak malicious links or attachments into conversations.

Why it’s dangerous:  These fake emails slip past naive checks. Users may not notice a tiny typo in the domain or that the “From” address is actually an external service. Victims might willingly click links or send confidential data, believing the email is legitimate. Unlike regular spam, spoofed emails exploit trust in your brand, so even savvy employees can be fooled. Without strict email authentication protocols (SPF, DKIM, DMARC) in place, it’s very hard to filter these out. (Industry experts note that fully-managed security can enforce and monitor these settings across all your mail servers.)

Malware and Ransomware via Email

What it is:  Cybercriminals use email to deliver malicious software. This can be hidden in attachments (e.g., macros in Word/Excel files, fake PDF invoices, ZIP files) or even embedded in the email body via advanced techniques like HTML smuggling. They may also use phishing links to direct users to infected websites. Recent trends show attackers abusing legitimate cloud services (e.g., Google Forms or Dropbox links) to host malware or credential harvesters, because spam filters tend to trust those domains. Even QR codes embedded in images or PDFs are now being used: a user scans a code in an email and is led to a phishing site, bypassing text-link filters.

Why it’s dangerous:  Email-delivered malware can lock your files or steal your data in an instant. According to U.S. cybersecurity agencies, phishing emails are the top method hackers use to spread ransomware. Once ransomware is in your system, it can encrypt critical data and demand a hefty payment to unlock it. For example, in April 2025, kidney care provider DaVita suffered a weekend ransomware attack that encrypted large parts of its network. Downtime followed, and executives scrambled to activate backups. Imagine even an SMB’s email going down for days: customers can’t be billed, orders are missed, and emergency recovery costs skyrocket. With 97% of ransomware infections delivered via Windows executables, an unwitting employee clicking an email link could trigger a major breach. The financial impact is severe – industry surveys show the average SMB loses hundreds of thousands of dollars to malware recovery.

AI-Driven Attacks and Deepfakes

What it is:  Attackers are increasingly using artificial intelligence to make their emails more convincing. AI can personalize phishing messages with your company or employee names, write flawless grammar, and even generate fake images or voices. For example, deepfake technology can synthesize a CEO’s voice asking the finance team to approve a wire transfer after receiving an email for context. One security expert warns that “AI will power significantly more phishing attacks – everything from text-based impersonations to deepfake communications will become cheaper, more convincing, and more popular with threat actors.

Why it’s dangerous:  AI-assisted scams are harder for humans to spot. A message that sounds or looks exactly like someone you trust breaks down the main defense – skepticism. Traditional spam filters also struggle: AI can generate messages that avoid blacklisted keywords and adapt phrasing on the fly. Worse, attackers can scale personalization across many targets quickly. For SMBs, this means every employee (not just the gullible ones) must be extra vigilant. Even training and awareness have to catch up: as attacks become more believable, “click rates” on phishing tests may rise unless defenses and education improve. Without specialist protection, these next-gen threats may enter inboxes unchecked.

Account Takeover & Email Thread Hijacking

What it is:  In an account takeover, a hacker breaks into a legitimate email account (say, a vendor or employee) and then uses it to send malicious messages. Even if they only have access briefly, they can forward ongoing conversations to the attacker. In thread hijacking, the attacker quietly inserts themselves into an active email exchange. For example, a criminal who compromises your vendor’s mailbox might reply to your invoice email with a new payment link. To you, it looks like a normal follow-up on an existing thread – virtually impossible to distinguish from a genuine reply. Or another example shared from one of the Answerssy´s engineers: An Enterprise network infrastructure company started experiencing bouncing messages due to a bad reputation. Our colleague's investigation found that a user was sending malicious emails. Further, it turned out that this user left the company 4 years ago, and his account had been hijacked.

Why it’s dangerous:  Because the email comes from a known contact and fits the conversation context, it bypasses most common filters and reduces suspicion. Victims often don’t realize they aren’t talking to the real person. This tactic has become popular with Business Email Compromise: attackers break a vendor’s account, wait for a legitimate email about payment, then intervene with a fake notice directing funds to themselves. The result is the same as BEC – lost money – but executed stealthily. Detecting and preventing these attacks requires advanced monitoring (e.g., spotting unusual forwarding rules or login patterns) that built-in email services typically don’t provide.

Why Default Email Security Isn’t Enough

All of the above threats show why basic email protection (the kind that comes free with your mailbox) is no longer sufficient. Out-of-the-box spam filters and antivirus software may catch generic junk or known malware, but they are blind to highly targeted scams. For example, many SMBs rely solely on Microsoft 365’s built-in email protection or on consumer-grade email clients. Experts call that a mistake: one industry analyst bluntly notes that “failure to invest in fully-managed email security services is another mistake small business owners make."

In practice, free/default tools won’t enforce strong email authentication (SPF/DKIM/DMARC), monitor 24/7, or adapt quickly to new evasion tricks. Consider this: 1 in 3 small businesses admit they use only free or consumer-grade cyber tools. Many don’t require multi-factor authentication on emails – in fact, only about 46% of SMBs have MFA enabled, leaving passwords as a single point of failure. Without specialized filtering and staff training, even savvy employees can be phished or manipulated. The end result: a malicious email slips in, and by the time you notice, it might already be too late.

In short, Gmail or basic Office-365 filtering is a starting point, but savvy SMBs know they need more. Adding a professional layer of protection can catch sophisticated BEC, detect spoofed domains, and flag the subtle signs of a hijacked account that ordinary filters miss.

The email security products (and next-generation firewalls) can really improve, but they still do not eliminate the risk. In most of the provided examples, security products are already in use. In fact, attackers exploit their vulnerabilities, too.

Reduce Risk – Outsource to Experts to handle these email security threats in 2025

Given the complexity and stakes, many SMB owners find it makes sense to outsource email security. Providers like Answerssy specialize in exactly these threats, and partnering with them can reduce risk, cost, and headaches. For example, Answerssy offers scalable monthly plans tailored to SMBs: their team will set up advanced threat filters, monitor your email around the clock, and provide ongoing phishing training for staff (see Answerssy’s Monthly Plans). This means you get enterprise-grade technology and expertise without hiring a full security team. In fact, security analysts note that outsourcing cyber defense “is guaranteed to save money” by avoiding expenses of training, salaries, and turnover for in-house staff.

By trusting specialists, you also gain quick incident response if an attack is suspected. Instead of scrambling alone during a breach, you have experts who already know your system and can act immediately. Answerssy’s engineers handle things like fine-tuning anti-spam rules, enforcing DMARC/PKI, and investigating suspicious logins for you. In practice, this greatly reduces the risk of a catastrophic email compromise and can even lower your insurance premiums (cyber insurers prefer clients with professional defenses). Plus, you free up your own IT time to focus on running the business, not chasing cyber threats.

Outsourcing doesn’t just cut risk – it cuts cost and complexity, too. Rather than buying and managing multiple point tools, an Answerssy plan bundles everything into one predictable monthly fee. You get expert reports, regular security updates, and as much support as you need. With no hidden surprises, SMBs often find this more affordable than building and refreshing an in-house solution.

Bottom line: Email threats are evolving fast, and default defenses alone can’t keep pace. By working with Answerssy’s email security specialists, your business gets stronger protection (and peace of mind) for less effort and expense.

Take Action Now: Don’t wait for a breach to act. Protect your business’s finances and reputation today. Contact Answerssy for a free consultation on your email security. The best time to shore up your defenses is before an attack arrives – let Answerssy help keep your inbox safe.

You can check: Our Monthly plans and bonus services; FBI for BEC; CISA (Cybersecurity & Infrastructure Security Agency)

Verizon Data Breach Report