If someone asked you right now what the most common way is that small businesses get breached, what would you say? A lot of people guess ransomware, or maybe a sophisticated hack of some kind. The answer is usually a lot more ordinary than that, and a lot harder to stop with the tools most small businesses are currently running.
In this article, we’re discussing the five major types of attacks that are hitting small businesses right now.
Phishing and Credential Theft
This is still the big one, and the 2026 Verizon Data Breach Investigations Report makes the picture clearer than ever. The human element was involved in 62% of breaches, with social engineering, phishing, and stolen credentials among the most frequent causes. Phishing accounted for 16% of initial access vectors on its own, but that number understates the real problem: phishing’s primary output is stolen credentials, and credential abuse appeared in 39% of full breach chains, making it the single most pervasive technique in the entire dataset.
What’s changed is how good phishing has gotten. AI-assisted phishing now accounts for 44% of AI-assisted initial access techniques, and attackers are using AI across the full attack chain. They are querying it for techniques, using it to build more convincing lures, and scaling campaigns that would previously have required significant manual effort. The email and the login page look real. So, your employee types their password and goes back to work.
A successful phishing attack doesn’t end with one stolen password. Attackers use that initial access to move further into your environment, accessing email to impersonate the victim, looking for financial accounts, finding other credentials stored in the inbox, or simply watching how your business operates before deciding what to do next. The password unlocks the door to your house. What’s behind it is what they came for.
Not sure how far an attacker would get if they used stolen credentials in your environment? That’s exactly what an internal penetration test is designed to find out, before someone else does. Let’s talk about what that looks like for your organization.
Credential Stuffing
This one doesn’t even require targeting your business specifically, which is part of why it’s so common. An attacker obtains a list of usernames and passwords from another site that was hacked, like a retail store, an old forum, or an app your employee signed up for years ago and completely forgot about, and runs those credentials against every business tool they can find. If your employee used the same password anywhere else that was ever breached, the attacker has a reasonable shot at getting in.
Credential stuffing accounted for 22% of all confirmed breaches in 2025, making it one of the most common breach vectors across all industries. The only thing that reliably stops credential stuffing is MFA, because a stolen password without the second factor gets an attacker nowhere.
Ransomware That Steals Before it Encrypts
The word ransomware tends to make people picture the moment their screen goes dark and a ransom note appears. However, people often don’t realize it’s the end of a process that started much earlier, and by the time it happens, a lot of damage has already been done.
Modern ransomware operators don’t break in and immediately lock everything up. They get in, stay quiet, and spend days or weeks moving through your environment to map your network, identify your most valuable data, and copy it out before they do anything visible. This is called double extortion, and it’s now standard practice rather than the exception. When the encryption finally happens, attackers already have your data. Restoring from backup gets your files back, but it doesn’t undo the theft. The threat to publish what they took is what gives them leverage even against organizations with good backup practices.
Your antivirus may or may not catch the encryption event depending on whether the ransomware variant is in its signature database. This is the category of threat that endpoint detection and response tools are specifically designed to catch, because they watch behavior rather than just scanning files.
Unpatched Software
Vulnerability exploitation as an initial access vector increased 34% year over year according to the Verizon Data Breach Investigations Report. With this type of attack, malicious actors look for software with known vulnerabilities that haven’t been patched yet. There are databases of known vulnerabilities, and there are automated tools that scan the internet looking for systems running unpatched versions. Your business doesn’t have to be specifically targeted for this to happen. It just has to be running software that hasn’t been updated.
Unlike phishing, this one doesn’t require any action from your employees. The vulnerability sits there until someone finds it.
Insider Threats and Human Error
74% of all breaches involve a human element. This can include human error, misuse of privileges, stolen credentials, or social engineering. This means the majority of breaches have a person at their center, whether intentionally or not.
These types of threats can look like a disgruntled employee copying files before they leave. It could be a well-meaning employee who clicked something they shouldn’t have, giving an attacker a foothold. Or it could be a former employee whose access was never fully revoked, so they can still log in to systems they haven’t worked with in months, with no one watching because no one remembers the account is still active.
None of these attacks are exotic. None of them require a sophisticated adversary with nation-state resources. They’re the everyday reality of what small businesses are dealing with, and they’re happening in environments where antivirus is installed, firewalls are running, and everyone generally assumes security is handled.
These five types of attacks are the findings that regularly show up in breach reports and in our own pen test results across industries and organization sizes. If you’d like to know where your business stands in relation to these threats, we’re glad to help you find out. MainNerve has been doing this work for over 20 years. Reach out today to set up a free consultation.
