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Introduction:
The recognition of elite security researchers like Devansh Chauhan by entities such as Berlin.de’s Hall of Fame underscores the critical importance of advanced, hands-on cybersecurity skills. This article distills the core technical competencies required to operate at this level, providing a practical toolkit for penetration testers, SOC analysts, and system administrators to proactively identify and mitigate vulnerabilities.
Learning Objectives:
- Master essential command-line techniques for reconnaissance, vulnerability assessment, and hardening across Linux and Windows environments.
- Implement advanced security configurations for web applications, APIs, and cloud infrastructure.
- Develop a methodology for ethical hacking that mirrors the approaches of top-tier bug bounty hunters and researchers.
You Should Know:
1. Network Reconnaissance and Enumeration
Before any assessment, understanding the target landscape is paramount. These commands provide a foundational view of the network and its services.
Nmap Top 1000 TCP Port Scan with Service Detection nmap -sS -sV --top-ports 1000 <target_ip> DNS Zone Transfer Attempt dig axfr @<dns_server> <domain_name> Subdomain Enumeration with Amass amass enum -active -d <target_domain> Directory and File Brute-forcing with Gobuster gobuster dir -u http://<target_url> -w /usr/share/wordlists/dirb/common.txt Identifying HTTP Security Headers curl -I http://<target_url> | grep -iE "(x-frame-options|x-content-type-options|strict-transport-security)"
Step-by-step guide: Begin with the `nmap` scan to map the attack surface. Follow with `dig` to test for misconfigured DNS, which can reveal internal network information. Use `amass` for passive and active subdomain discovery, then `gobuster` to find hidden directories. Finally, `curl` helps assess the basic web security posture by checking for critical missing headers.
2. Vulnerability Scanning and Analysis
Moving beyond reconnaissance, these commands help identify known vulnerabilities in services and web applications.
Vulnerability Scanning with Nikto nikto -h http://<target_url> Scanning for Common Web Vulnerabilities with Nuclei nuclei -u http://<target_url> -t /path/to/nuclei-templates/ Basic SQL Injection Test with SQLmap sqlmap -u "http://<target_url/page?id=1" --batch --level=1 OpenVAS Vulnerability Scan Execution openvas-cli --target <target_ip> --profile "Full and fast" --xml-output report.xml
Step-by-step guide: `Nikto` provides a quick, generic web server scan. `Nuclei` uses community-powered templates to detect a wide range of issues. For potential SQL injection points, `sqlmap` automates the exploitation and data extraction process. For a comprehensive internal network assessment, schedule an `openvas-cli` scan to generate a detailed XML report of system vulnerabilities.
3. Windows Security Hardening and Audit
A secure environment requires hardened endpoints. These PowerShell commands are essential for auditing and securing Windows systems.
Audit User Accounts and Privileges
Get-LocalUser | Format-Table Name, Enabled, LastLogon
Check Windows Firewall Status and Rules
Get-NetFirewallProfile | Select-Object Name, Enabled
Verify SMBv1 is Disabled (A Critical Vulnerability)
Get-WindowsOptionalFeature -Online -FeatureName SMB1Protocol
Check for Unquoted Service Path Vulnerabilities
Get-WmiObject -Class Win32_Service | Where-Object {$_.PathName -notlike "<code>"</code>""} | Select-Object Name, PathName
Step-by-step guide: Regularly run `Get-LocalUser` to identify inactive or unauthorized accounts. Ensure the firewall is enabled across all profiles. The `Get-WindowsOptionalFeature` command confirms SMBv1 is disabled to prevent wormable attacks. The WMI query for unquoted service paths helps find privilege escalation vectors that can be exploited.
4. Linux System Hardening and Integrity Monitoring
Linux servers are prime targets. These commands help lock down the OS and monitor for changes.
Check for Unauthorized SUID/SGID Files find / -perm -4000 -type f 2>/dev/null find / -perm -2000 -type f 2>/dev/null Verify File Integrity with AIDE aide --check Audit User Sudo Access sudo -l Harden SSH Configuration (Edit /etc/ssh/sshd_config) echo "Protocol 2" >> /etc/ssh/sshd_config echo "PermitRootLogin no" >> /etc/ssh/sshd_config echo "PasswordAuthentication no" >> /etc/ssh/sshd_config
Step-by-step guide: The `find` commands locate potentially dangerous executable permissions. `AIDE` creates a database of file hashes and attributes to detect unauthorized modifications. `sudo -l` reviews the current user’s sudo privileges. The `echo` commands append critical security settings to the SSH configuration to prevent brute-force and unauthorized root access.
5. API Security Testing
With the rise of microservices, API security is non-negotiable. These commands test for common API flaws.
Testing for Broken Object Level Authorization (BOLA) with curl
curl -H "Authorization: Bearer <token>" http://api.target.com/v1/users/123
curl -H "Authorization: Bearer <token>" http://api.target.com/v1/users/456
Fuzzing API Endpoints with FFUF
ffuf -w /usr/share/wordlists/api/endpoints.txt -u http://api.target.com/FUZZ
Checking for Missing API Rate Limiting
for i in {1..100}; do curl -s http://api.target.com/v1/data -o /dev/null; done
Step-by-step guide: Use `curl` with different user IDs in the endpoint to test for BOLA vulnerabilities. `FFUF` can discover hidden API endpoints by fuzzing common paths. The simple `for` loop script tests if the API has rate limiting enabled by sending 100 rapid requests; a successful execution indicates a potential DDoS vulnerability.
6. Cloud Infrastructure Hardening (AWS)
Misconfigured cloud resources are a leading cause of data breaches. These AWS CLI commands help audit your environment.
Check for Publicly Accessible S3 Buckets
aws s3api list-buckets --query "Buckets[].Name"
aws s3api get-bucket-acl --bucket <bucket_name>
Audit IAM Policies for Overly Permissive Rules
aws iam list-policies --scope Local --only-attached
Verify Security Groups for Overly Permissive Inbound Rules
aws ec2 describe-security-groups --filters Name=ip-permission.cidr,Values='0.0.0.0/0' --query "SecurityGroups[].{GroupName:GroupName, IpPermissions:IpPermissions}"
Step-by-step guide: List all S3 buckets and check their ACLs to ensure none are configured for public write/read. Review locally attached IAM policies to identify those granting excessive permissions ("Action": ""). The `ec2 describe-security-groups` command filters for security groups with rules open to the entire internet, a common critical misconfiguration.
7. Incident Response and Memory Forensics
When a breach is suspected, rapid response is key. These commands help in initial triage and evidence collection.
Live Network Connection Analysis (Linux) netstat -tunlp Process Tree Analysis ps auxf Capture RAM for Forensic Analysis (Requires LiME or similar) insmod lime.ko "path=/tmp/memdump.lime format=lime" Hunt for Rootkits with rkhunter rkhunter --check
Step-by-step guide: `netstat` identifies unexpected listening ports or established connections. `ps auxf` visualizes the process tree to spot anomalies or malicious processes. Loading the LiME kernel module allows for the capture of physical memory without altering its contents, which is vital for forensic investigation. Finally, `rkhunter` performs a scan for known rootkits and signs of compromise.
What Undercode Say:
- The Toolkit is Useless Without a Methodology: Possessing these commands is only 10% of the battle. The other 90% is developing the analytical mindset to know when, why, and in what order to use them. Top researchers like Chauhan succeed because they think like an attacker, chaining minor flaws into a critical breach.
- Automation is the Force Multiplier: The true power of these commands is realized when they are scripted and integrated into continuous security pipelines. Manual checks are prone to error and cannot scale. The future belongs to security engineers who can codify these checks to run autonomously against their entire environment.
The recognition of researchers on platforms like Berlin.de’s Hall of Fame is a direct result of applying this deep technical knowledge systematically. It’s not about running a single command; it’s about weaving dozens of these checks into a comprehensive security assessment that identifies the subtle weaknesses others miss. This approach transforms reactive security postures into proactive, intelligence-driven defense mechanisms.
Prediction:
The public recognition of elite security researchers will catalyze a shift in the cybersecurity landscape, legitimizing bug bounty hunting as a primary vector for organizational defense. This will lead to a 300% increase in crowdsourced security testing over the next three years. Consequently, the attack surface for malicious actors will shrink for organizations that embrace this model, while those that rely solely on traditional perimeter defense will suffer a disproportionate share of major breaches. The skills outlined in this article will become the baseline expectation for security professionals, not just specialists.
🎯Let’s Practice For Free:
IT/Security Reporter URL:
Reported By: Devansh Chauhan – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
