The answer is that an attacker performed a brute-force password attack and succeeded. This conclusion is drawn from the forensic pattern of multiple Event ID 4625 entries—each representing a failed logon attempt—followed by a single Event ID 4624, which records a successful logon. In a brute-force attack detection scenario, the rapid succession of 4625 failures against the same domain administrator account indicates systematic password guessing, and the subsequent 4624 confirms the attacker found the correct credential. On the Computer Hacking Forensic Investigator CHFI exam, this sequence tests your ability to correlate authentication failures with a successful breach, a common forensic artifact in incident response. A frequent trap is dismissing the 4624 as a legitimate user finally typing the correct password, but in a brute-force context, the clustered failures and the privileged target make compromise the most likely explanation. Memory tip: think “4625s are the hammer, 4624 is the door opening”—if the hammer stops and the door opens, someone broke in.
CHFI OS and Network Forensics Practice Question
This CHFI practice question tests your understanding of os and network forensics. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A security analyst reviewing Windows Security Event Logs sees multiple Event ID 4625 entries for a single user account, followed by a successful Event ID 4624. The account is a domain administrator. What is the MOST likely explanation?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
The user typed their password incorrectly several times before succeeding
Why wrong: A domain administrator is unlikely to mistype a password that many times in quick succession; this is more indicative of an automated attack.
B
The system experienced a denial of service attack
Why wrong: DOS attacks do not typically generate repeated failed logon events followed by success.
C
An attacker performed a brute-force password attack and succeeded
Multiple failed logon attempts followed by a successful logon, especially on a privileged account, strongly suggests a brute-force attack.
D
A misconfigured application caused repeated logon attempts
Why wrong: While possible, the pattern is classic for brute-force, especially with a privileged account.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
An attacker performed a brute-force password attack and succeeded
This pattern indicates a successful brute-force attack where the attacker guessed the password and then logged in successfully. Event ID 4625 indicates failed logon attempts, and Event ID 4624 indicates a successful logon.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The user typed their password incorrectly several times before succeeding
Why it's wrong here
A domain administrator is unlikely to mistype a password that many times in quick succession; this is more indicative of an automated attack.
✗
The system experienced a denial of service attack
Why it's wrong here
DOS attacks do not typically generate repeated failed logon events followed by success.
✓
An attacker performed a brute-force password attack and succeeded
Why this is correct
Multiple failed logon attempts followed by a successful logon, especially on a privileged account, strongly suggests a brute-force attack.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
✗
A misconfigured application caused repeated logon attempts
Why it's wrong here
While possible, the pattern is classic for brute-force, especially with a privileged account.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CHFI question in full detail.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related CHFI NAT questions on configuration and troubleshooting.
OS and Network Forensics — This question tests OS and Network Forensics — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: An attacker performed a brute-force password attack and succeeded — This pattern indicates a successful brute-force attack where the attacker guessed the password and then logged in successfully. Event ID 4625 indicates failed logon attempts, and Event ID 4624 indicates a successful logon.
What should I do if I get this CHFI question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related CHFI NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
About these practice questions
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A security analyst is reviewing Windows Security Event Logs and notices multiple Event ID 4625 entries for a single user account within a short time frame. What does this MOST likely indicate?
easy
✓ A.Brute-force password guessing attack
B.Service installation
C.Account lockout policy change
D.Successful account logon
Why A: Event ID 4625 indicates a failed logon attempt. Multiple failures in a short time suggest a brute-force attack against the user account.
Variation 2. A security analyst reviews Windows Security Event Log and notices multiple Event ID 4625 entries for a single user account from various IP addresses within a short time frame. What is the MOST likely attack being attempted?
easy
✓ A.Brute-force password attack
B.Kerberos golden ticket attack
C.ARP spoofing attack
D.Pass-the-hash attack
Why A: Event ID 4625 indicates a failed logon attempt. Multiple failures from different IPs in a short period is characteristic of a brute-force password guessing attack.
Last reviewed: Jun 21, 2026
Question Discussion
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This CHFI practice question is part of Courseiva's free EC-Council certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CHFI exam.
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