15 examples of security incidents affecting small businesses

Here are 15 examples of security incidents every small and mid-sized business should understand. In many cases, if you can detect and respond to these incidents, you can stop them from escalating into breaches.

What is a cybersecurity incident?

A cybersecurity incident is any occurrence that violates your security policies and controls. Incidents are often indicators of larger attacks against the confidentiality, integrity, or availability of your systems.

Incident vs breach: a security incident is any event that violates your policies and procedures; a breach is an incident that has escalated to the exposure of sensitive information. Incidents are usually precursors to breaches — investigate and respond to them well and you can often prevent the breach.

Every organization will have incidents. Identify your most critical assets and prioritize them when implementing controls. For an exhaustive catalog, MITRE ATT&CK is an excellent reference.

1. Unauthorized attempt to access systems or data

An attacker tries to reach devices or data they shouldn't — for example by phishing an employee for credentials. Mitigate: least privilege (including cloud/SaaS), MFA, and encryption of sensitive data at rest and in transit.

2. Privilege escalation

After gaining a foothold, an attacker tries to escalate from low-level to administrative access. Mitigate: a vulnerability-management program, secure baseline configurations, and a SIEM to alert on unusual activity.

3. Insider threats

Caused by employees or vendors, accidentally or intentionally — careless employees, pawns being manipulated, collaborators, and lone wolves. Mitigate: monitoring/SIEM, least privilege, and security-awareness training.

4. Phishing incidents

Attackers impersonate a person or company to get an employee to take a harmful action, usually via email or text. Mitigate: email authentication (SPF, DKIM, DMARC), awareness training, and an email security gateway.

5. Malware incidents

Ransomware, viruses, trojans, worms, adware, coin miners, and more, installed many different ways. Mitigate: effective endpoint protection and controlled administrative access so users work in non-admin accounts.

6. Denial of service

An attacker floods your systems with traffic until they're overloaded and unusable. Mitigate: configure firewalls/routers to block DoS traffic, and proxy public-facing servers behind DoS protection.

7. Man in the middle

An attacker intercepts and relays network communications, eavesdropping on everything that passes. Mitigate: encrypt data in motion (TLS/SSL), use WPA2 Wi-Fi, and train employees on public Wi-Fi risks and VPNs.

8. Password attack

Brute force, dictionary attacks, or phishing aimed at obtaining passwords. Mitigate: strong-password training, failed-login lockouts, and MFA.

9. Web application attack

Attackers target your websites/apps via SQL injection, known exploits, cross-site scripting, and more. Mitigate: review apps against the OWASP Top 10, use a web application firewall, and run regular penetration tests.

10. Loss or theft of equipment

A lost or stolen unencrypted laptop or phone can expose all its data — and under HIPAA this is treated as a reportable breach. Mitigate: encrypt mobile devices and keep sensitive data in central locations rather than on endpoints.

11. Removable media

USB drives and discs can carry scripts and malware onto your network. Mitigate: disable autorun, auto-scan removable media, and restrict which peripherals are allowed.

12. Improper disclosure of sensitive information

Sensitive data sent to the wrong party or left unprotected (misconfigured cloud buckets are a common culprit). Mitigate: train staff to verify recipients, and use configuration checklists when deploying services.

13. Port scanning

Attackers constantly scan the internet for open ports and the services behind them. Scans are frequent and usually not alarming on their own. Mitigate: use proxies/WAFs to detect scans, and configure systems not to respond to common techniques (e.g., PING).

14. Data exfiltration

Data actively leaving your network is a serious incident — it usually means attackers have already compromised and escalated. Mitigate: Data Loss Prevention, least privilege everywhere, and intrusion detection to spot abnormal traffic.

15. Improper disposal

Devices and paper records hold recoverable data. Don't just throw them away. Mitigate: follow NIST disposal best practices and train employees on them.

Conclusion

Everyone has security incidents. If you can contain them before they turn into breaches, you'll be far better off — which is why a solid incident response plan matters.