The answer is a ransom note displayed on screen and files with a changed extension such as .encrypted. These are common indicators of a ransomware attack because the ransomware payload first encrypts victim files using a strong cipher, then appends a new extension to mark them as locked, and finally drops a ransom note—often as a text file or pop-up—demanding payment for the decryption key. On the ISC2 Certified in Cybersecurity CC exam, this question tests your ability to recognize the immediate forensic artifacts of an active ransomware incident, distinguishing them from other malware like trojans or worms that may not alter file extensions. A common trap is confusing the ransom note alone as the only sign, but the extension change is equally critical because it proves encryption occurred. Memory tip: think “Note and New Ext” – if you see a ransom note and files with a strange suffix like .locked or .crypt, you are likely facing ransomware.
ISC2 CC Security Operations Practice Question
This CC practice question tests your understanding of security operations. 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 common indicators of a ransomware attack?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Files with .encrypted extension.
Option D is correct because ransomware commonly encrypts victim files and appends a new extension such as .encrypted to indicate the files have been locked. This extension change is a direct artifact of the encryption process performed by the ransomware payload, making it a key forensic indicator during incident response.
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.
✗
New user accounts created.
Why it's wrong here
Ransomware typically does not create new user accounts.
✗
Elevated system performance.
Why it's wrong here
Ransomware may cause performance degradation, not elevation.
✗
Sudden decrease in network traffic.
Why it's wrong here
Network traffic may increase due to encryption, not decrease.
✓
Files with .encrypted extension.
Why this is correct
Encrypted file extensions are a common sign of ransomware.
Related concept
Read the scenario before looking for a memorised answer.
✓
Ransom note displayed on screen.
Why this is correct
Ransom notes are a hallmark of ransomware.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
ISC2 often tests the distinction between ransomware indicators and general malware or intrusion indicators, so candidates mistakenly associate user account creation (Option A) with ransomware when it is actually a lateral movement technique, not a direct ransomware artifact.
Detailed technical explanation
How to think about this question
Ransomware typically uses symmetric encryption (e.g., AES-256) to encrypt files quickly, then encrypts the symmetric key with an asymmetric algorithm (e.g., RSA-2048). The .encrypted extension is often applied via a file rename operation after encryption completes, and the ransom note (e.g., 'README.txt' or 'HOW_TO_DECRYPT.html') is dropped in every affected directory. In real-world incidents, defenders use file system monitoring tools (like Sysmon Event ID 11) to detect mass file renames or extension changes as early warning signs.
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 developer is choosing between AES-256 (symmetric) and RSA-2048 (asymmetric) for encrypting a large file that will be sent to a partner. Symmetric encryption is fast but requires key exchange; asymmetric is slower but solves the key distribution problem. A hybrid approach — encrypt the file with AES, encrypt the AES key with RSA — is standard. Questions like this test whether you understand when each approach applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CC question in full detail.
Security Operations — This question tests Security Operations — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Files with .encrypted extension. — Option D is correct because ransomware commonly encrypts victim files and appends a new extension such as .encrypted to indicate the files have been locked. This extension change is a direct artifact of the encryption process performed by the ransomware payload, making it a key forensic indicator during incident response.
What should I do if I get this CC 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.
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This CC practice question is part of Courseiva's free ISC2 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 CC exam.
Question Discussion
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