Security Fundamentals What is the most common cause of security failures in computer systems?

Introduction / Context:
Security is only as strong as its weakest link. While sophisticated attacks exist, many breaches arise from basic lapses in user behavior rather than exotic zero-day exploits.

Given Data / Assumptions:

• Common user mistakes: weak passwords, password reuse, clicking phishing links, ignoring updates, and mishandling sensitive data.
• Technical controls exist but cannot fully mitigate careless actions.

Concept / Approach:
Assess which factor statistically accounts for the bulk of incidents. Numerous industry reports attribute a large percentage of compromises to human factors and social engineering, emphasizing training and process controls.

Step-by-Step Solution:
Identify typical breach vectors: phishing, credential stuffing, misconfigurations.Map them to user behavior (carelessness) versus purely technical shortcomings.Conclude that human error is the most prevalent root cause.

Verification / Alternative check:
Security postmortems repeatedly highlight unpatched systems, weak credentials, and phishing success rates as dominant factors—which are preventable with better user practices and governance.

Why Other Options Are Wrong:
Depending on passwords (Option B) is not inherently wrong; using strong, unique passwords with MFA is effective.Overemphasis on physical access (Option C) does not itself cause most breaches.“Insufficient technology” (Option D) matters, but even strong tech cannot compensate for unsafe behavior.

Common Pitfalls:

• Assuming technology alone solves security.
• Ignoring user training and phishing simulations.

Final Answer:
Carelessness by users (poor security hygiene).