The answer is the registry key HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\UpdateSvc, because persistence mechanisms are the most critical indicators of compromise to share when performing dynamic analysis for threat intelligence. While the outbound TCP connection to 198.51.100.10 on port 8080 is a valuable network IoC, the registry Run key directly reveals how the malware achieves autorun persistence, enabling the threat intelligence team to detect and remove the threat across endpoints. On the CHFI exam, this question tests your ability to prioritize IoCs that provide long-term detection value over transient network artifacts, as persistence indicators are more stable and less likely to change than IP addresses. A common trap is selecting the hosts file modification, which is often overwritten by security software, or the IP address, which may be rotated by attackers. Memory tip: think "Persistence First" — always prioritize registry Run keys, scheduled tasks, or service installations over network connections when asked for the most relevant IoCs from dynamic analysis.
CHFI Mobile and Malware Forensics Practice Question
This CHFI practice question tests your understanding of mobile and malware 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.
During dynamic analysis of a malware sample in a sandbox, an analyst observes the following behaviours: (1) A file is created at C:\Windows\System32\drivers\etc\hosts, (2) A registry key is set at HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\UpdateSvc, (3) Outbound TCP connections to 198.51.100.10 on port 8080. Which THREE of the following IoCs are MOST relevant to share with the threat intelligence team?
Why wrong: While hashes are useful, the question asks for the MOST relevant based on observed behaviours; the file hash is not described in the observation.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Network connection to 198.51.100.10:8080
Option B is correct because the outbound TCP connection to 198.51.100.10 on port 8080 is a direct network-based indicator of compromise (IoC) that threat intelligence teams can use to block or monitor malicious C2 traffic. This IP and port combination represents a specific command-and-control endpoint, making it highly actionable for network defense and threat hunting.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
MD5 hash of the original malware file
Why it's wrong here
While hashes are useful, the question asks for the MOST relevant based on observed behaviours; the file hash is not described in the observation.
✓
Network connection to 198.51.100.10:8080
Why this is correct
This is a network-based IoC indicating C2.
Related concept
Read the scenario before looking for a memorised answer.
Read the scenario before looking for a memorised answer.
✗
Mutex name created by the malware
Why it's wrong here
Mutex is not mentioned in the observed behaviours.
✓
File path C:\Windows\System32\drivers\etc\hosts
Why this is correct
Hosts file modification is a common technique for DNS poisoning or blocking.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
EC-Council often tests the distinction between observed behaviors (file creation, registry modification, network connections) and derived IoCs (hashes, mutexes), tricking candidates into selecting all listed options rather than only those directly tied to the observed actions.
Detailed technical explanation
How to think about this question
The hosts file at C:\Windows\System32\drivers\etc\hosts is a local DNS override mechanism; malware often modifies it to redirect legitimate domains to malicious IPs, bypassing DNS resolution. The registry Run key (HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run) is a classic persistence mechanism that executes the malware at every user login. The outbound TCP connection on port 8080, a common HTTP alternate port, indicates C2 communication, and sharing the IP:port pair allows threat intel teams to create firewall rules or sinkhole the traffic.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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.
Mobile and Malware Forensics — This question tests Mobile and Malware Forensics — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Network connection to 198.51.100.10:8080 — Option B is correct because the outbound TCP connection to 198.51.100.10 on port 8080 is a direct network-based indicator of compromise (IoC) that threat intelligence teams can use to block or monitor malicious C2 traffic. This IP and port combination represents a specific command-and-control endpoint, making it highly actionable for network defense and threat hunting.
What should I do if I get this CHFI question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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. During dynamic analysis of a malware sample, an analyst observes the following: creation of a mutex named `Global\{9A2D7E1C-3F4B-4A5E-9B8C-1D2E3F4A5B6C}`, a registry key under `HKCU\Software\Microsoft\Windows\CurrentVersion\Run` named `WindowsUpdate`, and outbound TCP traffic to `203.0.113.5:443`. Which THREE of the following indicators of compromise (IoCs) should be documented?
hard
✓ A.Outbound TCP to `203.0.113.5:443`
B.SHA256 hash of the malware sample
✓ C.Mutex name `Global\{9A2D7E1C-3F4B-4A5E-9B8C-1D2E3F4A5B6C}`
D.File path `C:\Windows\System32\notepad.exe`
✓ E.Registry key `HKCU\...\Run\WindowsUpdate`
Why A: Option A is correct because outbound TCP traffic to a specific IP address and port (203.0.113.5:443) is a classic network-based indicator of compromise (IoC). During dynamic analysis, this demonstrates the malware's command-and-control (C2) communication, often using HTTPS over port 443 to blend with legitimate traffic. Documenting this IoC allows defenders to block the endpoint and detect similar infections via network monitoring.
Variation 2. A security analyst runs a dynamic analysis of a suspected malware sample using Cuckoo Sandbox. The report shows that the sample created a mutex named 'Global\MyMaliciousMutex', added a registry run key under HKCU\Software\Microsoft\Windows\CurrentVersion\Run, and attempted to communicate with an IP address 185.10.68.12 on port 443. Which of the following is the BEST immediate indicator of compromise (IoC) to share with the threat intelligence team?
hard
A.The registry run key location
B.The sample's MD5 hash
✓ C.The IP address 185.10.68.12
D.The mutex name 'Global\MyMaliciousMutex'
Why C: The network C2 IP address is direct and actionable for blocklisting. Registry keys and mutex names can be used for detection but are less definitive for network defense.
Last reviewed: Jun 30, 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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