How Attackers Get In

“If you know the enemy and know yourself, you need not fear the result of a hundred battles” – Sun Tzu

When most people think about cyberattacks, they picture the aftermath: stolen data, locked-up computers, ransom notes, or reputational damage. But before any of that can happen, attackers have to get inside. Just like a burglar has to find a way into a house — through the front door, a window, or maybe the garage — cybercriminals rely on entry points to break into your business.

In our previous article on the Top Cybersecurity Threats Facing Small Businesses, we looked at the most common types of cyberattacks on small businesses: credential attacks, phishing, and ransomware.

In this article, we’re going one step deeper: how attackers actually gain initial access to your systems in the first place.

By understanding these “digital doorways,” into your systems and network, you’ll be in a much better position to close them off and strengthen your defenses. The truth is, most successful cyberattacks don’t rely on genius-level hackers or Hollywood-style tricks. They take advantage of simple weaknesses that many small businesses overlook.

In this article, we’ll break down the most common ways attackers get in, and show you practical steps to shut those doors before someone tries to walk through them. To help you understand the mechanics of initial access, we’ve grouped common attack patterns together:

• Social engineering: phishing, business email compromise
• External or exposed servers, services, and ports: websites, remote desktop, VPNs
• Web appplication logins: email, cloud services, social media
• Insider Threats: Carelessness or Malicious Intent

Social Engineering

Not every attack starts with fancy hacking tools. Often, the easiest way in is simply tricking a person. That’s what social engineering is: manipulating people into giving up access, information, or money.

Instead of breaking down firewalls, attackers break down trust. They might pretend to be your bank, a vendor, or even your coworker. The goal is to get you to click a link, open an attachment, share a password, or approve a payment.

Some common examples:

• Phishing emails — fake messages that look legitimate, urging you to “reset your password” or “view an invoice.”
• Phone scams (vishing) — a caller pretending to be tech support or the IRS, pressuring you to hand over info.
• Impersonation — showing up in person or online, claiming to be someone you trust.

For small businesses, social engineering is one of the biggest risks because attackers don’t need technical skill—just a good story and the right timing.

Small businesses are especially vulnerable because they rarely have dedicated IT or cybersecurity staff to filter out these threats. One mistake can mean stolen data, wire fraud, or ransomware.

Pro tip: Always verify before you trust. If something feels rushed or “off,” stop and double-check with a known contact method. A 30-second phone call can save you from a costly breach.

---

Why You Need To Defend Against Social Engineering

These attacks work because of two reasons. First, they play on human nature, often leveraging urgency, authority, and trust. If an email says “This is urgent, wire the funds now” or “Reset your password immediately”, people often act before they think. And in small businesses, where staff may not have much security training, it’s even easier for attackers to get away with it.

The second, technical, reason these attacks work is that, by nature, they get around the need for authentication (i.e. an attacker doesn’t need your password if they can phish you) and they often either don’t need malware or they use advanced malware, so basic defenses like antivirus and firewalls often aren’t effective against them.

There are several ways that small businesses can effectively detect and respond to these types of attacks, and we most-often recommend endpoint protection in the form of managed detection and response since most small businesses don’t have defensive cybersecurity personnel on staff. However, we recommend a series of initial steps to harden your devices and network against many types of attack including those that involve social engineering; just follow along with the Tasks in our course!

External or exposed servers, services, and ports

Small businesses often need systems that are reachable from the internet — a website, a remote-desktop server, a VPN concentrator, or a cloud database.

But anything you make reachable is a potential doorway. When servers, services, or ports are exposed without the proper protections, attackers can probe them, exploit weak settings, or use them as a beachhead to get deeper into your network.

• A server with a public IP and an open port (for example: RDP on 3389, SSH on 22, SMB on 445, or a database port).
• Cloud consoles, storage buckets, or management APIs left with weak permissions or public access.
• Web apps with outdated software or misconfigured admin pages reachable from the internet.

External vs exposed

The biggest risks come from systems on your network that are directly accessible from the internet. But don’t overlook what’s happening inside your own walls. Services running on internal machines — even if they’re “just” exposed to your local network — can still be abused if attackers get a foothold.

That’s why it’s critical to:

• Know what’s running. Keep track of which services are opening ports on every device.
• Shut down what you don’t need. Fewer services mean fewer ways in.
• Harden what must stay open. Use strong authentication and access controls to protect critical services.

In short: whether external or internal, every exposed service is a potential entry point. Visibility and control are your best defenses.

Why You Need to Defend Against Attacks on External or Exposed Servers, Services, and Ports

Attackers love exposed services because they’re easy to find and often overlooked on small networks. If a system is running with known vulnerabilities, default passwords, or overly generous access rules, an attacker doesn’t even need to “hack” — they just walk right in.

And once they’re in, the danger multiplies. From a single exposed server, an attacker can move sideways into file shares, backups, payroll systems, or customer data. What starts as a small hole can quickly snowball into a business-crippling breach.

Defenses include strong authentication, consistent patching, and regular system audits — all topics we’ll cover in this course. But for many small businesses, the most effective first step is a targeted vulnerability assessment. In a short engagement, a skilled practitioner can scan your entire network and pinpoint the weak spots that attackers would go after. It’s like having a friendly hacker check the doors before the bad guys do.

Web Application Logins: Email, Cloud Services, Social Media

For most small businesses, the real “front door” isn’t a server in a closet — it’s the apps you log into every day. Email, file storage, accounting platforms, social media accounts, even scheduling tools. Each login is a potential entry point, and attackers know these are often less protected than traditional IT systems.

They target web application logins because they’re easy to reach and often poorly defended. Anyone on the internet can try a login page, and automated tools can attempt thousands of guesses without much effort. Weak or reused passwords make this even easier — one stolen password from a past data breach can unlock multiple accounts if it’s been reused.

In addition to using strong, unique passwords, multi-factor authentication (MFA) is the best way to severely disable the ability of an attacker to conduct an attack on your web application logins. Not only does MFA add a layer of security in terms of an attacker needing to gain access to an additional account or device you control, it also prevent the type of repeated login attempts used in brute force or password spray attacks. When multi-factor authentication (MFA) isn’t turned on, a single stolen password is all it often takes for an attacker to get in, move around, and potentially gain control of your email, data, or customer-facing accounts.

Why You Need to Defend Against Web Application Login Attacks

For attackers, stolen logins are gold. They don’t need to break into your network if they can simply walk in through the same apps you and your employees use every day. Email accounts are especially valuable, because once inside, attackers can reset passwords for other services, impersonate you in phishing scams, or quietly monitor communications to time a wire fraud attempt.

Cloud storage logins can expose sensitive business files, contracts, or customer data. Hijacked social media accounts can damage your reputation and even be used to trick your clients into clicking malicious links. In short: the impact of a compromised account often spreads far beyond the account itself.

Industry data shows just how common this is: credential-based attacks remain one of the most frequent ways cybercriminals gain initial access. For small businesses, this is especially dangerous because many rely on a handful of shared apps for critical operations. One weak password or unprotected account can disrupt payroll, lock you out of your own data, or erode customer trust overnight.

Insider Threats: Carelessness or Malicious Intent

Not every cyber incident starts with an outsider. Sometimes the danger comes from inside the business itself. An “insider threat” can be as simple as an employee clicking on a phishing email, or as serious as a disgruntled staff member stealing data on their way out the door.

Most insider issues aren’t malicious — they’re mistakes. Accidentally sending sensitive files to the wrong person, using weak passwords, or plugging in an infected USB drive can all open the door to attackers. But intentional threats do exist, and small businesses are not immune. An unhappy employee with access to payroll, customer records, or shared drives can cause real damage if they decide to misuse that access.

For small businesses, this is especially challenging because teams are small and trust runs deep. Owners often assume “it could never happen here.” Unfortunately, attackers know this and sometimes even recruit insiders to help them.

The key to managing insider threats is balance: protect your business without treating every employee like a suspect. Clear policies, role-based access controls, regular security training, and prompt offboarding of former staff go a long way. Add in monitoring for unusual behavior, and you can catch problems early — before they turn into costly incidents.

Another issue with small businesses can be the lack of consistent company culture with historical precedent. At a big company, everyone knows that if an employee decides to act maliciously against the company, they will be prosecuted to the fullest extent. They also know that IT has the capability to see what they’re doing and provide any evidence needed in court. Small businesses often don’t have the benefit of this type of culture, and can become prey to their employees on a bad day, or frequently, after letting their employees go. If they aren’t logging what happens on their systems, they may not be in a position to prosecute a former employee who behaved maliciously.

The Impact of Security Culture

Another challenge for small businesses is the lack of a clear security culture. At large companies, employees understand that if someone acts maliciously, IT can track what happened and provide evidence for legal action. That awareness alone discourages bad behavior.

In small businesses, those guardrails aren’t always in place. Logging may be minimal, monitoring may be absent, and former employees may still have lingering access. This creates an environment where a frustrated worker — or someone who’s just been let go — can cause harm without fear of accountability. Without records of who did what, even pursuing legal action becomes difficult.

The good news is that small businesses can build a healthier culture that both supports employees and reduces insider risk. It doesn’t have to be heavy-handed or adversarial. A few practical steps include:

• Set expectations clearly. Share simple security policies in plain language so employees understand what’s allowed, what isn’t, and why.
• Promote accountability. Let staff know that activity on company systems is logged — not as “spying,” but as a standard safeguard to protect both the business and its employees.
• Foster trust and openness. Encourage employees to raise concerns about security or suspicious behavior without fear of blame.
• Leverage the Principle of Least Privilege. Only provide employees with enough access to do their job – something also called Least Privilege Access.
• Handle offboarding consistently. Make it part of company culture that when someone leaves — even on the best of terms — their access is removed immediately.
• Lead by example. When leadership follows the same rules (using MFA, strong passwords, secure file sharing), employees are far more likely to take them seriously.

Creating this kind of positive security culture helps employees see themselves as part of the defense, not the problem. And when people understand both the responsibility and the consequences, the business is in a far stronger position to deter insider threats.

Pro tip: Always remove access immediately when an employee leaves, even if the departure is on good terms. Forgotten accounts are one of the most common insider risk blind spots.