Listen to this Post
Introduction:
The modern cybersecurity landscape demands proficiency across a multitude of operating systems and tools. Mastery of core commands is not just beneficial—it’s fundamental to effective defense, penetration testing, and incident response. This guide consolidates the critical commands and procedures every security practitioner needs in their arsenal.
Learning Objectives:
- To acquire practical, executable knowledge of fundamental Linux and Windows security commands.
- To understand how to leverage these commands for system hardening, vulnerability assessment, and digital forensics.
- To build a foundational skill set for advanced cybersecurity operations and penetration testing.
You Should Know:
1. Network Reconnaissance with Nmap
Nmap is the industry standard for network discovery and security auditing. It is used to discover hosts and services on a computer network by sending packets and analyzing the responses.
`nmap -sS -sV -O -T4 `
Step‑by‑step guide:
1. Open your terminal.
- Type the command `nmap -sS -sV -O -T4 192.168.1.105` (replace the IP with your target).
3. `-sS`: Performs a stealth SYN scan.
-sV: Probes open ports to determine service/version info.
5. `-O`: Enables OS detection.
6. `-T4`: Aggressive timing template for faster scans.
- Analyze the output to map the network and identify potential entry points.
2. Vulnerability Scanning with Nessus
While GUI-based, Nessus is driven by its powerful backend commands for management and automation.
`/opt/nessus/sbin/nessuscli fetch –register `
Step‑by‑step guide:
- Download the Nessus package for your Linux distribution.
- Install it using your system’s package manager (e.g.,
sudo dpkg -i Nessus-.deb). - Start the Nessus service:
sudo systemctl start nessusd. - Register the scanner using the `nessuscli fetch –register` command with your activation code.
- Access the web interface at `https://localhost:8834` to configure and launch scans.
3. Web Application Testing with OWASP ZAP
The OWASP ZAP Baseline scan is ideal for automated, CI/CD-integrated security testing.
`docker run -t owasp/zap2docker-stable zap-baseline.py -t https://www.undercode.test`
Step‑by‑step guide:
1. Ensure Docker is installed on your system.
- Run the command, replacing the target URL with your web application’s address.
- The tool will automatically spider the target and run a suite of passive security tests.
- Review the output in the terminal for a list of discovered vulnerabilities, such as missing security headers or CSP issues.
4. Linux Process and Network Analysis
Understanding what is running on a system is critical for identifying malicious activity.
`ss -tulwnp | grep LISTEN`
`lsof -p `
`ps aux | grep -i `
Step‑by‑step guide:
- List all listening ports and the processes using them:
ss -tulwnp. - Identify a suspicious process and note its PID.
- List all files opened by that PID:
lsof -p 1234. - To find a specific process, use `ps aux | grep -i sshd` to see all SSH daemon processes.
- This helps in pinpointing unauthorized services or connections.
5. Windows Log Analysis and Sysinternals
The Windows command line is a powerful tool for live response and forensics.
`wevtutil qe Security /f:text /rd:true /q:”[System[(EventID=4624)]]” | findstr “LogonType”`
`.\Sysinternals\PsExec.exe -i -s cmd`
Step‑by‑step guide:
- To query the Security event log for successful logons (Event ID 4624), use the `wevtutil` command. Filter for “LogonType” to understand the logon method (e.g., Network vs Interactive).
- For deep system analysis, use tools from the Sysinternals suite. The `PsExec` command shown allows you to execute commands with SYSTEM-level privileges, which is crucial for investigating system-level persistence or malware.
6. Cloud Security Hardening (AWS CLI)
Misconfigured cloud storage is a leading cause of data breaches. The AWS CLI allows for rapid auditing.
`aws s3api get-bucket-acl –bucket my-bucket –query “Grants[?Grantee.URI== ‘http://acs.amazonaws.com/groups/global/AllUsers’]”`
`aws s3api put-bucket-acl –bucket my-bucket –acl private`
Step‑by‑step guide:
- Configure your AWS CLI with credentials that have read permissions.
- Check a bucket for public access using the `get-bucket-acl` command. It will return a result if the bucket is world-readable.
- To remediate, immediately set the bucket to private using the `put-bucket-acl` command.
- Automate this check across all buckets in your environment for continuous compliance.
7. API Security Testing with curl
The ubiquitous `curl` command is invaluable for manually testing API endpoints for common vulnerabilities.
`curl -X POST -H “Content-Type: application/json” -d ‘{“user”:”admin”, “password”:”password”}’ https://api.target.com/login -k -v`
`curl -H “Authorization: Bearer
Step‑by‑step guide:
- Test for broken authentication by fuzzing login endpoints with common credentials using the `-d` (data) flag.
- Use the `-v` (verbose) flag to inspect the full HTTP request and response, including headers.
- Test authorization controls by taking a valid JWT token and accessing privileged endpoints to see if they fail properly (Broken Object Level Authorization – BOLA).
- The `-k` flag allows testing against sites with self-signed certificates for internal pentests.
What Undercode Say:
- Foundational Fluency is Non-Negotiable: Automation and GUI tools are powerful, but they build upon a foundation of core command-line knowledge. A professional who cannot navigate a system without a GUI is severely limited in their ability to respond to novel threats or operate in constrained environments.
- Context is King: A command is just a string of text without the analytical framework to interpret its output. The true skill lies not in memorization, but in understanding what the results mean for the security posture of the system, application, or network you are assessing.
The provided LinkedIn post, while a celebratory milestone for a researcher, underscores the professional outcomes of mastering these skills: successful bug bounty submissions and career advancement. The call to “Join our WhatsApp group” hints at the community-driven nature of skill development in this field. The future of cybersecurity will be shaped by professionals who blend automated tooling with deep, command-level expertise to identify and mitigate vulnerabilities that machines alone cannot find.
Prediction:
The convergence of AI-powered offensive security tools with traditional command-line proficiency will define the next era of cybersecurity. While AI will automate the discovery of low-hanging fruit and pattern-based vulnerabilities, the sophisticated, logic-based exploits that yield the highest rewards will still require human intuition, guided by a deep understanding of systems through their fundamental commands. The analysts and hunters who thrive will be those who use AI as a force multiplier for their core skills, not as a replacement.
🎯Let’s Practice For Free:
IT/Security Reporter URL:
Reported By: https://lnkd.in/p/ddSKaD6u – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
