The Most Common Cyberattacks on Small Businesses

Most small business owners operate under a dangerous assumption: that hackers target large corporations, not businesses with 10, 50, or 200 employees. The data tells a completely different story. According to the Verizon Data Breach Investigations Report, small businesses are the target of over 43% of all cyberattacks — and nearly 60% of small businesses that suffer a significant breach close their doors within six months of the incident.

The reason is straightforward: small businesses hold valuable data — customer records, payment information, employee details, intellectual property — but typically invest far less in cybersecurity than the enterprises cybercriminals also target. That gap between the value of the data and the strength of the defenses makes small businesses among the most attractive targets in the threat landscape.

This guide covers the most common cyberattacks targeting small businesses today, explains exactly how each one works, and gives you actionable defenses you can implement without a dedicated IT security team.

1. Phishing Attacks — The Most Widespread Threat

Phishing is consistently ranked as the single most common vector for cyberattacks on businesses of every size — and it remains devastatingly effective despite being one of the oldest attack types in existence. The reason is simple: it bypasses technical defenses entirely by targeting human psychology instead of software vulnerabilities.

How phishing works

In a phishing attack, a cybercriminal sends an email — or increasingly, a text message (smishing) or phone call (vishing) — that impersonates a trusted entity. The message creates urgency: a suspicious login on your bank account, an overdue invoice from a vendor, a password expiration notice from your email provider, a package delivery problem. The victim clicks a link, is directed to a convincing fake website, and enters credentials that are immediately harvested by the attacker.

Modern phishing has evolved far beyond the obvious broken-English scam emails of the early 2000s. Today’s attacks use:

Spear phishing — targeted attacks personalized with the victim’s name, job title, company name, and even references to recent events pulled from LinkedIn or social media. These are dramatically more convincing than mass phishing campaigns.
Business Email Compromise (BEC) — attackers impersonate a company’s CEO, CFO, or a trusted vendor and instruct an employee to urgently wire funds or change payment account details. The FBI reports that BEC scams have caused over $50 billion in global losses.
Clone phishing — a legitimate email previously received by the target is replicated exactly, but with links replaced by malicious ones. The sender appears identical to the original.

How to defend against phishing

Implement multi-factor authentication (MFA) on all business accounts — email, banking, cloud storage, and any system containing sensitive data. Even if credentials are stolen through phishing, MFA prevents account access without the second factor.
Deploy email filtering and anti-phishing software (Microsoft Defender for Office 365, Proofpoint, or Mimecast) that identifies and quarantines suspicious messages before they reach inboxes.
Conduct regular phishing simulation training — services like KnowBe4 or Proofpoint Security Awareness send simulated phishing emails to employees and provide training to those who click. Repeated exposure dramatically reduces click rates over time.
Establish a verbal verification protocol for any financial transaction or account change requested by email, regardless of who the sender appears to be. One phone call to a known number can prevent a six-figure wire transfer fraud.

2. Ransomware — The Most Destructive Attack

If phishing is the most common attack, ransomware is the most devastating. In a ransomware attack, malicious software encrypts all of the victim’s accessible files — documents, databases, backups, financial records — making them completely inaccessible. The attacker then demands a ransom, typically paid in cryptocurrency, in exchange for the decryption key.

How ransomware reaches small businesses

Ransomware rarely arrives in isolation. It is almost always the payload delivered after another initial compromise method succeeds — most commonly phishing, but also through:

Remote Desktop Protocol (RDP) exploitation — Many small businesses expose RDP (the Windows remote access tool) directly to the internet. Attackers scan for open RDP ports and brute-force weak passwords to gain entry, then deploy ransomware manually after exploring the network.
Malicious email attachments — A Word document with a malicious macro, a fake invoice PDF, or a compressed archive containing an executable file.
Drive-by downloads — Visiting a compromised or malicious website automatically downloads and executes ransomware without any user interaction beyond the page load.
Supply chain attacks — Attackers compromise software used by many businesses and distribute malware through legitimate update channels.

The modern ransomware threat: double extortion

Contemporary ransomware attacks have evolved beyond simple encryption. In what security researchers call “double extortion,” attackers first exfiltrate (steal) the victim’s data before encrypting it. They then threaten to publish the stolen data on leak sites unless the ransom is paid — meaning that even businesses with perfect backups face pressure to pay to prevent customer data, financial records, or proprietary information from being publicly released.

How to defend against ransomware

Maintain offline backups following the 3-2-1 rule: three copies of data, on two different media types, with one copy stored offline or air-gapped. Ransomware cannot encrypt backups it cannot reach. Test your backups regularly — a backup you cannot restore from is not a backup.
Patch and update all software religiously. The majority of successful ransomware attacks exploit known vulnerabilities for which patches already exist. Delayed updates are open invitations.
Restrict RDP access — disable it when not needed, use a VPN rather than direct internet exposure, and enforce strong passwords with account lockout policies.
Deploy Endpoint Detection and Response (EDR) software on all devices. Modern EDR solutions detect ransomware-like behavior (mass file encryption) and can terminate the process before it completes, limiting damage significantly.
Implement network segmentation — isolate critical systems so that a ransomware infection on one workstation cannot propagate freely to servers, backups, and all other connected machines.

3. Social Engineering — Manipulating People, Not Systems

Social engineering is the art of manipulating people into revealing confidential information or taking actions that compromise security — without any malware, exploit, or technical hacking required. It exploits fundamental human tendencies: helpfulness, authority deference, urgency response, and fear of consequences.

Common social engineering tactics targeting small businesses

Pretexting: The attacker invents a fabricated scenario — posing as an IT support technician, an auditor, a new vendor, or a government official — to create a convincing reason for their request. “Hi, I’m from your payroll provider and I need to verify your account details before your direct deposits process tomorrow” is a pretext designed to extract banking credentials.

Vishing (voice phishing): Phone calls impersonating banks, the IRS, Microsoft support, or other authoritative entities. The caller creates urgency (“your account has been compromised and will be frozen in one hour”) and guides the victim through actions that hand over access or financial resources.

Tailgating and physical access: An attacker follows an authorized employee into a secure area by exploiting social courtesy — holding a door open for someone carrying packages is a natural instinct that attackers deliberately exploit to gain physical access to office spaces, server rooms, or unattended workstations.

Quid pro quo: The attacker offers something of value — “I can fix your computer problem remotely right now” — in exchange for credentials or remote access.

How to defend against social engineering

Build a security-aware culture where employees feel empowered to verify requests and decline them without social discomfort. The phrase “I need to verify that through our standard process” should be normalized for any request involving credentials, money, or access.
Implement strict identity verification procedures for anyone requesting access to systems or sensitive information — especially over the phone or via email.
Run regular security awareness training that includes social engineering scenarios, not just phishing simulations. Employees who recognize the tactics are dramatically less susceptible to them.

4. Man-in-the-Middle Attacks — Intercepting Your Communications

In a Man-in-the-Middle (MitM) attack, a cybercriminal secretly positions themselves between two communicating parties — typically a user and a website or application — intercepting and potentially altering the data flowing between them. The victim believes they are communicating directly and securely with the intended destination. They are not.

How MitM attacks target small businesses

The most common vectors for MitM attacks against small businesses involve unsecured or attacker-controlled networks:

Public Wi-Fi interception: Employees working from coffee shops, airports, or hotels connect to unencrypted public Wi-Fi. An attacker on the same network can intercept unencrypted traffic, capturing login credentials, session tokens, and sensitive data transmitted without proper encryption.

Evil twin attacks: An attacker sets up a Wi-Fi access point with a name identical or similar to a legitimate network — “Starbucks_WiFi” vs. “StarbucksWiFi” — and waits for devices to connect. All traffic from connected devices flows through the attacker’s equipment.

SSL stripping: The attacker downgrades an HTTPS connection to HTTP, stripping the encryption and allowing all traffic to be read in plain text. Many users do not notice the missing padlock in their browser.

ARP spoofing: On a local network, the attacker sends falsified ARP (Address Resolution Protocol) messages to associate their MAC address with a legitimate IP address — redirecting traffic destined for a router or server through their device instead.

How to defend against MitM attacks

Require a company VPN for all employees accessing business systems remotely or on any network other than the office. A VPN encrypts all traffic end-to-end, making interception useless even on compromised networks.
Enforce HTTPS-only browsing via browser policy and ensure your company website and any web applications enforce HTTPS with valid, up-to-date SSL/TLS certificates.
Implement certificate pinning in any custom applications to prevent SSL stripping attacks.
Educate employees to avoid conducting business on public Wi-Fi without a VPN — particularly any activity involving credentials, financial data, or customer information.

5. Password Attacks — Exploiting Weak Credential Hygiene

Despite decades of warnings, weak and reused passwords remain one of the primary causes of small business security breaches. Password attacks exploit this endemic problem through multiple techniques, ranging from brute force to sophisticated credential stuffing campaigns using billions of previously breached passwords.

Types of password attacks

Brute force attacks: Automated tools systematically try every possible password combination. Short, simple passwords fall in seconds. An 8-character password using only lowercase letters has approximately 200 billion possible combinations — a modern GPU can try 100 billion per second, cracking it almost instantly. A 16-character password mixing letters, numbers, and symbols has more combinations than current technology can exhaust.

Dictionary attacks: Rather than trying every combination, attackers use lists of common passwords, words, and known patterns. “Password123,” “Summer2024!” and “CompanyName1” all fall to dictionary attacks almost immediately.

Credential stuffing: When a website is breached and passwords are stolen, those credentials are compiled into databases and sold on dark web marketplaces. Attackers then automatically test those username/password combinations against hundreds of other websites and services. Because most people reuse passwords across multiple accounts, credential stuffing succeeds at a disturbing rate — even against accounts on platforms that were never themselves breached.

Password spraying: Instead of trying many passwords against one account (which triggers lockouts), attackers try one common password against thousands of accounts simultaneously. “Spring2025!” tested against every employee email address at your domain is a password spray — and it finds victims without triggering any single account lockout.

How to defend against password attacks

Deploy a password manager (Bitwarden, 1Password, or Keeper) across the entire organization. Password managers generate and store long, unique, random passwords for every account — eliminating reuse and making brute force attacks computationally infeasible.
Enforce multi-factor authentication on every account that supports it. Even a perfectly stolen password is useless to an attacker who cannot produce the second factor.
Set account lockout policies that temporarily lock accounts after a defined number of failed login attempts, making brute force and password spraying attacks impractical.
Check your organization’s email domains against Have I Been Pwned (haveibeenpwned.com) to identify accounts with credentials in known breach databases — and require immediate password changes for any matches.

6. SQL Injection — Attacking Your Web Applications and Databases

If your small business operates a website with a login system, a contact form, a shopping cart, or any interface that accepts user input and communicates with a database, SQL injection is a direct threat. It is consistently ranked among the most critical web application vulnerabilities and has been responsible for some of the largest data breaches in history.

How SQL injection works

A web application that accepts user input — a login form, a search bar, an order number field — typically constructs a database query using that input. In a vulnerable application, an attacker can insert (inject) malicious SQL code into the input field. The database receives and executes that code as a legitimate command, potentially:

Bypassing authentication entirely (logging in without a valid password)
Extracting the entire contents of the database — including all customer records, payment data, and credentials
Modifying or deleting database records
In some configurations, executing commands on the underlying server

A classic example: a login form expecting a username and password. An attacker enters ' OR '1'='1 in the username field. The resulting SQL query always returns true, bypassing authentication completely. This is a decades-old technique — and it still works against surprising numbers of small business websites built without adequate security review.

How to defend against SQL injection

Use parameterized queries and prepared statements in all database interactions. This separates SQL code from user-supplied data structurally, making injection impossible regardless of what input the user provides.
Deploy a Web Application Firewall (WAF) — services like Cloudflare WAF, AWS WAF, or Sucuri detect and block SQL injection attempts before they reach your application.
Conduct regular security audits and penetration testing of any web application that handles customer data. Annual third-party penetration tests are the most reliable way to identify SQL injection vulnerabilities before attackers find them.
Implement least-privilege database access — the database user account used by your web application should have only the minimum permissions needed for its function. A compromised account with read-only access causes far less damage than one with administrative privileges.

7. Insider Threats — The Danger From Within

Not all cyberattacks originate outside the organization. Insider threats — security incidents caused by current or former employees, contractors, or business partners who have legitimate access to systems — represent one of the most difficult threat categories to defend against, precisely because the attacker already has authorized access.

Types of insider threats

Malicious insiders: Employees who deliberately steal data, sabotage systems, or facilitate external attacks — motivated by financial gain, grievance, or coercion. A departing employee who downloads the entire customer database before their last day is a malicious insider incident. A disgruntled employee who deletes critical files or intentionally misconfigures systems is another.

Negligent insiders: Far more common than malicious actors, negligent insiders cause incidents through carelessness — clicking phishing links, using weak passwords, misconfiguring cloud storage to be publicly accessible, losing devices containing sensitive data, or sharing credentials with colleagues “for convenience.” The 2023 IBM Cost of a Data Breach Report found that negligent employees are involved in a substantial portion of all breach incidents.

Compromised insiders: An employee whose credentials have been stolen by external attackers effectively becomes an insider threat — the attacker operates using legitimate access, making their activity harder to distinguish from normal behavior.

How to defend against insider threats

Implement least-privilege access control rigorously — employees should have access only to the specific systems and data required for their role, nothing more. A marketing employee has no legitimate business need to access the financial database.
Maintain a robust offboarding procedure that immediately revokes all system access, deactivates credentials, and retrieves company devices the moment an employee’s departure is confirmed — including in voluntary resignations.
Enable audit logging and monitoring on all critical systems. Logs of who accessed what, when, and from where are the primary investigative tool when an insider incident occurs — and their existence alone deters some opportunistic theft.
Establish clear data handling policies and ensure all employees understand them. Many negligent insider incidents result from employees who did not realize their actions were prohibited or risky, rather than from deliberate wrongdoing.

8. Supply Chain Attacks — Compromised Through Trusted Vendors

One of the most sophisticated and rapidly growing threat categories targets small businesses not directly, but through the software, services, and vendors they trust. In a supply chain attack, an adversary compromises a third-party supplier — an IT service provider, a software vendor, a cloud platform — and uses that foothold to reach the supplier’s customers downstream.

Why supply chain attacks are particularly dangerous for small businesses

Small businesses frequently rely on third-party managed service providers (MSPs) for IT management, accounting software, HR platforms, payment processing, and cloud infrastructure. These relationships require trusting the vendor with significant access to business systems. When that vendor is compromised, every business in their customer portfolio becomes a potential target — and the attack arrives through a trusted, whitelisted channel that security tools are specifically configured not to block.

The SolarWinds attack of 2020 and the Kaseya VSA attack of 2021 — in which thousands of businesses were compromised through trusted IT management software — demonstrated the scale and sophistication of supply chain attacks at the enterprise level. Similar but less publicized incidents targeting small business software vendors occur regularly.

How to defend against supply chain attacks

Conduct vendor security assessments before granting any third party significant access to your systems. Ask about their security practices, incident response procedures, and breach history. A vendor who cannot answer these questions clearly is a risk.
Apply least-privilege access to vendor relationships — grant third parties only the specific access needed for their service, review those permissions regularly, and revoke immediately when the relationship ends.
Monitor vendor-related activity in your systems. Unusual access patterns from a vendor account — at unusual hours, from unusual locations, accessing data outside their normal scope — should trigger investigation.
Stay current on security advisories from your software vendors. When a vendor discloses a breach or a critical vulnerability in their software, your response speed is critical to limiting exposure.

9. DNS Spoofing and Domain Hijacking

Domain Name System (DNS) attacks target the internet’s address book — the system that translates human-readable domain names like “yourbusiness.com” into the IP addresses computers use to communicate. When DNS is compromised, attackers can silently redirect your employees or customers to malicious destinations they believe are legitimate.

DNS spoofing (DNS cache poisoning)

In DNS cache poisoning, an attacker corrupts the DNS cache of a resolver — the server that answers DNS queries — with false information. When a user types your website’s domain into their browser, the poisoned resolver returns the attacker’s IP address instead of yours, directing the user to a fraudulent site designed to steal credentials or deliver malware. The user sees your domain name in their browser but is communicating with an attacker’s server.

Domain hijacking

Domain hijacking occurs when an attacker gains unauthorized access to your domain registrar account and changes the DNS records — redirecting your domain to a server they control, or transferring the domain out of your registrar entirely. The consequences can be catastrophic: your website goes offline or becomes a phishing site, your email is intercepted or rerouted, and reclaiming the domain can take days to weeks even after the attack is discovered.

How to defend against DNS attacks

Enable DNSSEC (DNS Security Extensions) on your domain — a protocol that digitally signs DNS records, making cache poisoning attacks significantly harder to execute successfully.
Use a reputable, security-focused DNS provider (Cloudflare 1.1.1.1, Google 8.8.8.8, or Cisco Umbrella for businesses) rather than default ISP DNS servers, which may have weaker security postures.
Secure your domain registrar account with a strong, unique password and multi-factor authentication. Enable registrar lock to prevent unauthorized domain transfers.
Set up domain monitoring alerts that notify you immediately of any DNS record changes — services like DNSlytics or your registrar’s built-in notifications can catch unauthorized changes before they cause lasting damage.

10. DDoS Attacks — Taking Your Business Offline

A Distributed Denial of Service (DDoS) attack floods a target’s servers, network infrastructure, or internet connection with traffic at a volume that overwhelms capacity and makes legitimate access impossible. For a small business that depends on its website for sales, bookings, or customer service, even a brief DDoS attack can cause significant revenue loss and reputational damage.

How DDoS attacks work

Modern DDoS attacks leverage botnets — networks of thousands or millions of compromised devices (computers, IoT devices, routers) controlled by the attacker — to generate traffic volumes that individual servers cannot withstand. Attack sizes measured in terabits per second are now recorded regularly. A small business web server rated for normal traffic volumes is completely unprepared for this scale of assault.

DDoS attacks are increasingly used not just to cause disruption, but as smokescreens. While IT staff scramble to restore service, attackers use the distraction to conduct other malicious activities — data exfiltration, lateral movement, or credential theft — that proceed undetected during the chaos.

How to defend against DDoS attacks

Use a DDoS mitigation service — Cloudflare (free tier available), AWS Shield, or Akamai provide absorptive capacity that can handle large-scale attacks by filtering malicious traffic before it reaches your infrastructure.
Host your website on a cloud provider with built-in DDoS protection rather than a single on-premises server. Cloud infrastructure scales dynamically and provides inherent resilience that fixed hardware cannot match.
Develop a DDoS response plan before an attack occurs — know who to contact, what failover options exist, and how to communicate with customers during an outage. Response speed matters enormously in limiting the business impact of a successful attack.

Building Your Small Business Cybersecurity Defense: A Prioritized Action Plan

Understanding the threats is necessary; acting on that understanding is what actually protects your business. The following action plan is organized by priority — start at the top, and each completed step meaningfully reduces your overall risk profile.

Immediate actions (this week)

Enable multi-factor authentication on every business account: email, banking, cloud storage, and any platform containing customer data. This single control prevents the majority of account takeover attacks regardless of how credentials are obtained.
Deploy a password manager across all employees. Eliminate shared passwords, simple passwords, and password reuse across accounts. This week, not eventually.
Verify that all software, operating systems, and firmware are fully up to date. Enable automatic updates wherever possible. Unpatched systems are the most avoidable vulnerability in any small business environment.
Confirm that your most critical data — customer records, financial data, operational systems — is backed up offline or in an air-gapped location that ransomware cannot reach. Test that the backup actually restores correctly.

Short-term actions (next 30–90 days)

Implement security awareness training for all employees. A single trained employee who recognizes and reports a phishing attempt can prevent a six-figure breach. Untrained employees are the most reliably exploited attack surface in any organization.
Review access permissions across all systems. Remove access that is no longer needed. Ensure former employees have zero remaining access. Apply least-privilege principles throughout.
Deploy endpoint protection software — at minimum, a reputable antivirus on all devices; ideally, an EDR (Endpoint Detection and Response) solution on any system accessing sensitive data.
Establish a VPN requirement for all remote work. Any employee accessing business systems outside the office should do so only through a corporate VPN.
Add Cloudflare or equivalent DDoS and WAF protection in front of your website, particularly if it handles customer transactions or login credentials.

Ongoing practices

Conduct quarterly review of vendor access and permissions. Revoke anything that is no longer current or necessary.
Run annual penetration testing on any web applications or externally facing systems. Third-party testers find what internal teams miss.
Maintain and test your incident response plan at least annually. Knowing exactly what to do in the first hours of a breach dramatically limits the damage from one.
Stay current on the threat landscape through resources like the Cybersecurity and Infrastructure Security Agency (CISA), the SANS Internet Stormcenter, and Krebs on Security. The threat environment evolves faster than any static document can capture.

The Bottom Line

Small businesses are not too small to be targeted. They are, in the eyes of cybercriminals, the ideal target: valuable data, accessible systems, and defenses that rarely match those of the enterprises whose security teams dedicate entire careers to this problem.

The cyberattacks described in this guide — phishing, ransomware, social engineering, password attacks, SQL injection, insider threats, supply chain compromises, DNS attacks, and DDoS — are not theoretical risks. They are the documented, measured reality of the current threat environment, occurring millions of times per day against businesses exactly like yours.

The encouraging truth is that the most impactful defenses are not the most expensive or technically complex ones. Multi-factor authentication, regular backups, security awareness training, patch management, and least-privilege access control collectively address the majority of successful attacks. These are not advanced security measures — they are basic hygiene. But in a threat landscape where most attackers look for the easiest available target, basic hygiene makes your business substantially less attractive than the alternative.

Cybersecurity is not a problem to be permanently solved. It is a continuous practice — updated as threats evolve, reinforced as new vulnerabilities emerge, and maintained with the same regularity as any other critical business function. The businesses that treat it as such are the ones that remain operational when their less-prepared competitors do not.

Frequently Asked Questions

What is the most common cyberattack on small businesses?

Phishing is consistently the most common initial attack vector — it accounts for the majority of data breaches and security incidents across all business sizes. Ransomware is typically the most destructive outcome, often delivered through phishing as an initial compromise. Addressing phishing through training and multi-factor authentication provides the broadest risk reduction available to small businesses.

How much does a cyberattack cost a small business?

The average cost of a data breach for small and medium-sized businesses ranges from $120,000 to over $1 million depending on the type of attack, data involved, and regulatory obligations. This includes direct costs (ransomware payments, forensics, recovery) and indirect costs (downtime, lost customers, reputational damage). For many small businesses, a significant breach is an existential event rather than a recoverable setback.

Do small businesses need a dedicated cybersecurity team?

Not necessarily. Many essential cybersecurity controls — MFA, password managers, backup solutions, email filtering, endpoint protection — can be deployed and managed without dedicated security staff. For businesses that lack internal IT resources, a reputable Managed Security Service Provider (MSSP) can provide enterprise-grade security operations at a fraction of the cost of building internal capability. The key is ensuring someone owns the responsibility, whether internal or external.

What should a small business do immediately after discovering a cyberattack?

Contain the incident first — disconnect affected systems from the network to prevent spread. Do not turn off affected machines, as volatile memory may contain forensic evidence. Contact your cyber insurance provider (if you have one) and a cybersecurity incident response firm. Notify relevant stakeholders and, depending on the data involved, you may have legal obligations to notify affected customers and regulatory authorities within specific timeframes. Document everything from the moment of discovery.

Is cyber insurance worth it for small businesses?

For most small businesses, cyber insurance is a worthwhile risk management tool — particularly as coverage has become more standardized and accessible at lower price points. A good policy covers incident response costs, legal fees, regulatory notification expenses, and sometimes ransom payments. Insurers also increasingly provide pre-breach security resources and incident response services to policyholders. Compare policies carefully, paying attention to exclusions and coverage limits for ransomware, as these vary significantly between providers.

We recommend checking out this article:

What To Do Immediately After a Cyberattack

It’s a great follow-up if you want to keep exploring similar content and get more useful insights.