Anomalous behavior: risky, unexpected, unintentional

5.6 Security awareness

📘CompTIA Security+ (SY0-701)


In cybersecurity, anomalous behavior means any action by a user, system, or device that is unusual, unexpected, or risky. Detecting these behaviors is important because they often indicate a security problem, such as an insider threat, malware, or a human mistake that could lead to data loss.

Anomalous behavior is generally classified into three main types:


1. Risky Behavior

Definition: Actions that increase the chance of a security incident or breach. These behaviors are intentional but unsafe.

Examples in IT:

  • Clicking links in emails from unknown senders (phishing risk).
  • Sharing passwords or credentials with others.
  • Downloading unverified software from the internet.
  • Using weak or default passwords for sensitive accounts.

Why it matters:
Risky behavior can open the door for attackers. Even a single risky action can compromise an entire system or network.


2. Unexpected Behavior

Definition: Actions that are unusual for a user, system, or device. This may indicate a security incident or a misconfigured system.

Examples in IT:

  • A user suddenly accessing files they normally never touch (could indicate insider threat or compromised account).
  • A server suddenly sending large amounts of data outside the network (possible data exfiltration).
  • A device starting to communicate with an unknown external IP address (possible malware or hacker activity).

Why it matters:
Unexpected behavior can help detect attacks early. Security systems often use monitoring tools and alerts to flag these anomalies.


3. Unintentional Behavior

Definition: Actions that cause a security problem, but without malicious intent. These are usually mistakes by users.

Examples in IT:

  • Accidentally sending an internal document to the wrong external email address.
  • Misconfiguring firewall rules or cloud storage permissions.
  • Storing sensitive files in a public folder.
  • Forgetting to update software or apply security patches.

Why it matters:
Even unintentional behavior can lead to data breaches, system downtime, or regulatory violations.


How Organizations Detect Anomalous Behavior

To protect systems, IT teams use various tools to detect anomalous behaviors:

  1. Security Information and Event Management (SIEM) systems – collect logs and alert unusual activity.
  2. User and Entity Behavior Analytics (UEBA) – track user or device behavior patterns and flag deviations.
  3. Endpoint Detection and Response (EDR) – monitors devices for unusual or risky activity.

Example:
If a user normally accesses their email and a few project folders, but suddenly downloads hundreds of files at 2 a.m., the system may flag this as anomalous behavior.


Key Takeaways for the Exam

  • Anomalous behavior can be risky, unexpected, or unintentional.
  • All three types can indicate a security threat or mistake.
  • Detecting these behaviors is critical to preventing breaches.
  • Tools like SIEM, UEBA, and EDR are commonly used to monitor and respond.
  • Security awareness training can reduce risky and unintentional behaviors.

Simple Summary

Think of anomalous behavior as “something is off.” It could be:

  • Risky → user is doing something unsafe on purpose.
  • Unexpected → something unusual is happening.
  • Unintentional → a mistake caused a potential security issue.

By teaching employees to recognize risky actions and using monitoring tools for unexpected events, organizations can reduce security incidents significantly.

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