hardMultiple Select
Evidence Handling Best Practices for Incident Investigation
Which THREE of the following are best practices for handling evidence during an incident investigation?
Quick Answer
The answer is to create a forensic image of the affected systems, as this preserves the original data in a bit-for-bit copy, ensuring that the evidence remains unaltered for analysis. This practice is critical because any direct examination of live systems can modify metadata, timestamps, or file contents, breaking the chain of custody and rendering evidence inadmissible. On the Certified Information Security Manager CISM exam, this concept tests your understanding of forensic soundness and legal admissibility, often appearing in questions about incident response procedures. A common trap is confusing logical backups with forensic images—logical copies do not capture deleted files or slack space, while forensic images do. Remember the mnemonic "F.I.R.E.": Forensic Image, Integrity, Record, Examine—always image first before any live analysis to maintain evidentiary purity.
⚠ Common exam trap
Many exam-takers confuse 'analyze evidence directly on live systems' (Option C) as acceptable for speed, but CISM emphasizes preservation of evidence integrity over expedience, and 'store evidence in its original location' (Option E) may seem logical but violates the principle of securing evidence in a controlled chain of custody.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Document all actions taken during evidence collection.
Option A is correct because documenting every action taken during evidence collection creates an auditable record that preserves the integrity and admissibility of the evidence, showing exactly who did what and when. Option B is correct because a chain of custody log tracks the seizure, transfer, and storage of evidence, ensuring it has not been tampered with and remains admissible in legal or disciplinary proceedings. Option D is correct because creating a forensic image (a bit-for-bit copy, typically verified with a hash such as MD5 or SHA-256) allows analysis to be performed on the copy while preserving the original evidence in its unaltered state. Option C is not a best practice because analyzing evidence directly on live systems can alter timestamps, memory contents, and file metadata, destroying or contaminating potential evidence; analysis should be done on forensic copies. Option E is not a best practice because evidence should be collected, documented, and stored securely in a controlled location rather than left in place, where it could be modified, lost, or compromised.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Document all actions taken during evidence collection.
Why this is correct
Contemporaneous documentation records every action, tool and timestamp during collection, preserving evidential integrity and enabling the investigation to be reconstructed and defended. This satisfies the best-practice requirement for accountability and auditability throughout the incident investigation.
- ✓
Maintain a chain of custody log.
Why this is correct
A chain of custody log records who handled, transferred and stored each item, with times and signatures. This unbroken record proves evidence was not tampered with or contaminated, satisfying the investigation's requirement for admissibility and integrity of collected artefacts.
- ✗
Analyze evidence directly on live systems to avoid delays.
Why it's wrong here
Analysing evidence on live systems alters timestamps, memory and file metadata, destroying forensic integrity and admissibility. Proper practise is write-blocked imaging and analysis on copies. Live analysis is tempting when speed matters or systems cannot be taken offline, but it contaminates the evidence chain.
- ✓
Create a forensic image of the affected systems.
Why this is correct
A forensic image is a bit-for-bit copy of the affected system's storage, captured before analysis so the original remains unaltered. Working from the image preserves volatile and deleted data, satisfying the investigation's requirement that evidence stay forensically sound and defensible.
- ✗
Store evidence in its original location to avoid disturbance.
Why it's wrong here
Leaving evidence in place lets anyone alter or destroy it, breaking chain of custody and forensic integrity. It is tempting because undisturbed originals are ideal in theory, but the correct practise is to photograph, document and then copy or seize items so their state is preserved and provable.
Go deeper
Related to this question
About these practice questions
This CISM question is part of Courseiva's 924-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more way this is tested on CISM
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 best practices for preserving digital evidence during an incident? (Select exactly 2)
easy- ✓ A.Create a forensic image of the hard drive using a write blocker
- ✓ B.Document the chain of custody
- C.Interview witnesses before collecting data
- D.Run antivirus scans on the affected system
- E.Reboot the system to clear memory
Why A: Creating a forensic image with a write blocker (Option A) is a best practice because it captures an exact bit-for-bit copy of the storage media without altering the original data. The write blocker intercepts write commands at the hardware or software level, ensuring the integrity of the evidence. This preserves the original state for later analysis and admissibility in legal proceedings.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CISM practice question is part of Courseiva's free ISACA 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 CISM exam.