The correct answer is cron job exploitation via script modification, because a writable script executed by a root-owned cron job allows a low-privileged user to inject arbitrary commands that will run with root privileges when the job triggers. This classic privilege escalation via writable cron script works by overwriting the script’s contents—for example, adding a reverse shell or a SUID binary—so that the next scheduled execution grants full control of the system. On the CompTIA PenTest+ PT0-002 exam, this scenario tests your ability to identify misconfigured file permissions in scheduled tasks, often appearing as a multiple-choice question where a trap answer suggests exploiting a SUID binary instead. The key insight is that the cron job’s owner (root) determines the execution context, not the script’s owner. Memory tip: “Write to the script, ride the root cron.”
PT0-002 Attacks and Exploits Practice Question
This PT0-002 practice question tests your understanding of attacks and exploits. 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 a penetration test, a tester gains access to a Linux server as a low-privileged user. The server has a cron job that executes a script owned by root but writable by the tester's group. Which privilege escalation technique should the tester use?
Why wrong: While kernel exploits can escalate privileges, the scenario does not mention an outdated kernel or available exploit, and the cron vulnerability is directly exploitable.
B
Misconfigured sudo permissions
Why wrong: No sudo configuration or command is mentioned; the tester's group has write access to the script, not sudo privileges.
C
Cron job exploitation via script modification
The tester can modify the script that is executed as root by the cron job. When the job runs, the injected code executes with root privileges.
D
Path hijacking in the cron job
Why wrong: Path hijacking would involve replacing a command used in the script, but the script itself is writable, so direct modification is simpler and more reliable.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Cron job exploitation via script modification
The cron job executes a script owned by root but writable by the tester's group. This means the tester can modify the script's contents. When the cron job runs (as root), the modified script executes with root privileges, allowing the tester to gain a root shell or execute arbitrary commands as root. This is a classic cron job exploitation via script modification.
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.
✗
Kernel exploit
Why it's wrong here
While kernel exploits can escalate privileges, the scenario does not mention an outdated kernel or available exploit, and the cron vulnerability is directly exploitable.
✗
Misconfigured sudo permissions
Why it's wrong here
No sudo configuration or command is mentioned; the tester's group has write access to the script, not sudo privileges.
✓
Cron job exploitation via script modification
Why this is correct
The tester can modify the script that is executed as root by the cron job. When the job runs, the injected code executes with root privileges.
Related concept
Read the scenario before looking for a memorised answer.
✗
Path hijacking in the cron job
Why it's wrong here
Path hijacking would involve replacing a command used in the script, but the script itself is writable, so direct modification is simpler and more reliable.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may confuse path hijacking (which exploits an unqualified command in the script) with direct script modification (which exploits writable permissions on the script file itself), but the question explicitly states the script is writable, making modification the correct choice.
Trap categories for this question
Command / output trap
No sudo configuration or command is mentioned; the tester's group has write access to the script, not sudo privileges.
Scenario analysis trap
While kernel exploits can escalate privileges, the scenario does not mention an outdated kernel or available exploit, and the cron vulnerability is directly exploitable.
Detailed technical explanation
How to think about this question
Cron jobs run with the privileges of the user who owns the crontab file (in this case root). If a script executed by cron is writable by a lower-privileged user, that user can inject commands (e.g., adding a reverse shell or copying /bin/bash to a SUID binary). The cron daemon (crond) does not check file integrity or ownership changes between reads; it simply executes the script at the scheduled time. In real-world engagements, testers often use `echo 'cp /bin/bash /tmp/rootbash; chmod +s /tmp/rootbash' >> /path/to/script` to create a SUID root shell.
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: Cron job exploitation via script modification — The cron job executes a script owned by root but writable by the tester's group. This means the tester can modify the script's contents. When the cron job runs (as root), the modified script executes with root privileges, allowing the tester to gain a root shell or execute arbitrary commands as root. This is a classic cron job exploitation via script modification.
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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