Attacker
An attacker is a person, system, or process that intentionally attempts to compromise the security, availability, or integrity of a system.
“A person or process that attempts to access data, functions or other restricted areas of the system without authorization, potentially with malicious intent.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Attacker?
An attacker performs malicious actions to exploit vulnerabilities, steal information, disrupt services, or gain unauthorized access. Understanding attacker behavior helps testers design effective security tests.
Types of attackers: Attackers may be external hackers, insiders, competitors, or automated systems.
Motivation: Attackers may seek financial gain, data theft, disruption, or unauthorized access.
Testing value: Security testing often simulates attacker behavior to identify weaknesses before real attacks occur.
Real World Example
An online banking login flow is being reviewed after fraud analysts report repeated attempts to discover valid customer accounts.
The concern is not whether ordinary login works; it is how the system behaves when someone intentionally misuses it. Attacker points testing toward that hostile or risky behavior.
The tester probes rate limits, error messages, audit events, lockout behavior, and monitoring signals to see whether the system gives attackers useful feedback.
The team strengthens the controls because Attacker helps them test the product from the perspective of misuse, not only normal customer journeys.
Practice Questions
Question 1
Which description BEST reflects an attacker model useful for testing?
Question 2
Which test MOST aligns with an insider attacker model?
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