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Difficulty: MediumCommon Network Attack Types and Vectors

A network security administrator reviews authentication logs for a corporate Remote Access VPN gateway and notices a pattern of authentication failures across over 500 distinct employee accounts within a short timeframe. Further inspection shows that each individual account experienced only two failed login attempts per hour, avoiding account lockout thresholds. Which of the following attack types is most likely occurring?

  1. Password spraying attackAnswer
  2. B
    Brute-force dictionary attack against a single account
  3. C
    DNS cache poisoning attack targeting record lookup resolution
  4. D
    Port scanning and SNMP community string enumeration over port 161

Answer

Password spraying attack
Password spraying is a technique where an attacker attempts a few common passwords (e.g., 'Summer2026!') against a vast list of usernames. By keeping the number of failed attempts low per account within a given time period, the attacker successfully circumvents automated account lockout mechanisms.

Step-by-Step Solution

1
Analyze the log signature provided in the scenario.
Identified multiple user accounts (500+) receiving a low frequency of failed attempts (2 per hour), deliberately designed to stay beneath account lockout policies.
Security controls typically lock an account after 3 to 5 failed attempts within a set window; attackers adapt by testing a few common passwords across many accounts.
2
Compare the signature against common attack vectors.
Password spraying specifically fits the pattern of horizontal testing (few passwords across many accounts), whereas traditional brute-force is vertical testing (many passwords against one account).
Distinguishing between horizontal and vertical credential attacks is critical for deploying appropriate mitigations such as multi-factor authentication (MFA).

Key Concept

Password Spraying Attack
Estimated Time:1m 15s
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Topics

Common Network Attack Types and Vectors

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