The answer is Alternate Data Streams (ADS) and slack space. These are the two valid methods to hide data on an NTFS file system without using external tools because both are native NTFS features that exploit the file system’s own structure. ADS allows data to be appended to a file as a hidden stream, invisible to standard directory listings, while slack space uses the unused bytes between the end of a file and the end of its allocated cluster. On the Computer Hacking Forensic Investigator CHFI exam, this question tests your understanding of file system forensics and anti-forensics, often appearing as a trap where candidates might mistakenly choose third-party tools or encryption. A common memory tip is to remember that both methods are “free” and “built-in”—no downloads needed, just the file system itself. Think of ADS as a secret pocket on a file and slack space as the empty padding in a box; both are invisible unless you specifically look for them.
CHFI Storage Forensics and File System Analysis Practice Question
This CHFI practice question tests your understanding of storage forensics and file system analysis. 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.
Which TWO of the following are valid methods to hide data on an NTFS file system without using external tools?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Embedding data in file slack space
Alternate Data Streams (ADS) allow hiding data within a file's stream. Slack space (file slack) can hide data in unused bytes between the end of file and end of cluster. Both are native NTFS features.
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.
✓
Embedding data in file slack space
Why this is correct
File slack is unused space at the end of a cluster that can be filled with data.
Related concept
Static NAT maps one inside address to one outside address.
✗
Storing data in the NTFS file system journal ($LogFile)
Why it's wrong here
The journal is not designed for data hiding; it logs transactions.
✗
Using the $Volume attribute in the MFT
Why it's wrong here
$Volume is a system attribute, not for data hiding.
✗
Encrypting data with EFS
Why it's wrong here
EFS encrypts, but does not hide existence of data.
✓
Using Alternate Data Streams (ADS)
Why this is correct
ADS can hide data in streams attached to files.
Related concept
Static NAT maps one inside address to one outside address.
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.
Storage Forensics and File System Analysis — This question tests Storage Forensics and File System Analysis — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: Embedding data in file slack space — Alternate Data Streams (ADS) allow hiding data within a file's stream. Slack space (file slack) can hide data in unused bytes between the end of file and end of cluster. Both are native NTFS features.
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.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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. Which TWO of the following are methods used to hide data within the NTFS file system?
medium
A.USN Journal
✓ B.File slack space
C.Volume Shadow Copy
✓ D.Alternate Data Streams (ADS)
E.Encrypting File System (EFS)
Why B: ADS allows hiding data in streams attached to files, and slack space can hide data in unused bytes at the end of file clusters.
Variation 2. Which TWO of the following are valid methods for hiding data on an NTFS volume without using third-party tools? (Select 2)
medium
A.Creating a symbolic link to a hidden file
B.Encrypting the file with EFS
✓ C.Slack space (file slack or volume slack)
✓ D.Alternate Data Streams (ADS)
E.Using the $Recycle.bin folder
Why C: Alternate Data Streams (ADS) and slack space are native NTFS features that can be used to conceal data.
Last reviewed: Jun 21, 2026
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.