CompTIA CySA+ (CS0-003)Security OperationsEasy

A SOC analyst is investigating an alert from the SIEM indicating a high number of failed login attempts against a public-facing web application originating from a single source IP address (192.168.1.100). The logs show hundreds of attempts within a few minutes, each using a different username and password combination. What type of attack is most likely occurring?

  1. ACross-Site Scripting (XSS)
  2. BBrute-Force Attack
  3. CDenial of Service (DoS)
  4. DSQL Injection
Show answer & explanation

Correct answer: B. Brute-Force Attack

A brute-force attack involves systematically trying many password combinations for a target user, or many username/password combinations, until the correct one is found. The scenario describes a high number of failed login attempts with different credentials from a single source, which is characteristic of a brute-force attack.

Why the other options are wrong

  • A. XSS injects malicious scripts into web pages, not a direct login attack.
  • C. DoS aims to make a service unavailable, not to gain unauthorized access via login.
  • D. SQL injection targets database vulnerabilities, not login credentials.

Brute-Force Attack

An attack method that involves systematically trying every possible combination of characters or words to guess a password, encryption key, or find a hidden web page.

  • Often targets authentication mechanisms.
  • Can use dictionaries or generate all possible combinations.
  • Indicators include numerous failed login attempts from a single source or to a single account.

Memory trick: Web apps face many attack types; brute-force is about guessing.

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