Operating Systems & Endpoints

Windows/Linux basics, processes, persistence, and endpoint triage.

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Showing 10 of 10

OS-01

Where do you typically find Windows security logs?

Answer: In Event Viewer under Windows Logs → Security (and also System/Application). Centralized logs may be forwarded to a SIEM.

Tip: Know examples: logon events, account changes, service installs, scheduled tasks.

OS-02

Where are common Linux logs stored?

Answer: Usually under /var/log (e.g., auth.log/secure, syslog/messages, journalctl for systemd).

Tip: Be comfortable with grep, tail, less, and journalctl queries.

OS-03

How would you quickly assess a suspicious process on Windows?

Answer: Check process name/path, parent process, command line, hash, signed status, and network connections; correlate with recent file writes and user context.

Tip: Sysinternals Process Explorer is a common approach (even if your org uses EDR).

OS-04

How would you quickly assess a suspicious process on Linux?

Answer: Use ps/top, check command line and parent (ps -ef), validate binary path, inspect network sockets (ss/netstat), and review auth/system logs around the time of execution.

Tip: Look for unusual locations (e.g., /tmp, /dev/shm) and odd persistence mechanisms.

OS-05

What is “persistence” and give 3 examples on endpoints.

Answer: Persistence is how malware survives reboots and maintains access. Examples: scheduled tasks, startup/run keys, services (Windows); cron jobs, systemd services, rc scripts (Linux).

Tip: In interviews, name specific locations/keys (e.g., Run/RunOnce).

OS-06

What is the Windows Registry and why is it useful in investigations?

Answer: A database for configuration and system settings. It’s often used for persistence and stores artifacts about execution, installed software, and user activity.

Tip: Mention common persistence keys and that EDR often records registry modifications.

OS-07

How do you check for suspicious user accounts?

Answer: Review local/domain account creation, group membership changes, recent logons, and privileged roles; validate against HR/IT change records.

Tip: Look for “new admin” accounts, unusual naming patterns, and logons at odd hours.

OS-08

Explain the idea of least privilege.

Answer: Users and services should have only the minimum permissions needed. It reduces blast radius when accounts are compromised.

Tip: Tie it to SOC: privilege abuse is common; watch for admin group changes and token elevation.

OS-09

User-mode vs kernel-mode malware—what’s the difference?

Answer: User-mode runs with standard process privileges; kernel-mode runs in the OS core, can hide deeper, and is harder to detect/remove.

Tip: You don’t need deep RE knowledge—just show you understand impact and detection difficulty.

OS-10

What endpoint signals help determine if an alert is real?

Answer: Process lineage, command line, file hash reputation, network destinations, persistence attempts, lateral movement artifacts, and user context.

Tip: Answer like a triage playbook: validate → scope → contain if needed.