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Introduction:
The Romanian National Cyber Security Directorate (DNSC) is recruiting for 12 critical incident handling and response roles, highlighting the intense global demand for skilled cybersecurity professionals. This hiring surge reflects the escalating threat landscape and the critical need for analysts who can monitor, analyze, and neutralize cyber threats around the clock. Securing such a position requires not just theoretical knowledge but also practical, hands-on proficiency with the tools and commands that form the backbone of modern security operations.
Learning Objectives:
- Understand the core technical skills required for roles in a National CERT or SOC.
- Master essential Linux and Windows command-line tools for incident analysis.
- Learn key commands for network monitoring, log analysis, and vulnerability assessment.
You Should Know:
1. Network Traffic Analysis with tcpdump
Before an analyst can respond to an incident, they must first identify it. Network packet analysis is a fundamental skill for monitoring and detecting malicious activity.
`tcpdump -i eth0 -n -c 50 port 80`
`tcpdump -i any -w suspect_traffic.pcap host 192.168.1.100`
`tcpdump -r suspect_traffic.pcap -A ‘tcp[bash] & 4 != 0’`
Step-by-step guide:
- The first command listens on interface `eth0` (
-i eth0), avoids converting addresses to names (-n), and captures 50 packets (-c 50) on port 80. - The second command captures all traffic to or from the host `192.168.1.100` on any interface (
-i any) and writes the raw packets to a file `suspect_traffic.pcap` for later, deeper analysis. - The third command reads from the saved capture file (
-r suspect_traffic.pcap) and prints the ASCII content (-A) of packets that have the RST flag set ('tcp[bash] & 4 != 0'), which can indicate aborted connections.
- Incident Triage with Linux Process and Network Inspection
When a host is suspected of being compromised, the first step is to get a snapshot of running processes and their network connections.
`ps aux –sort=-%mem | head -10`
`netstat -tulnpa`
`lsof -i -P -n`
`ss -tulnpa`
Step-by-step guide:
– `ps aux` lists all running processes. Piping it to `sort` and `head` (--sort=-%mem | head -10) shows the top 10 processes by memory usage, helping to identify potential resource-hogging malware.
– `netstat -tulnpa` displays all listening (-l) and established TCP/UDP ports (-tu), without resolving names (-n), and shows the associated process/program (-p).
– `lsof -i -P -n` is a powerful alternative that lists all open Internet files (network connections), showing the process, PID, and user, without resolving port numbers (-P) or hostnames (-n).
3. Windows Forensic Artifact Collection
On a Windows endpoint, crucial evidence for an incident is stored in logs, the registry, and active network connections.
`Get-Process | Where-Object {$_.CPU -gt 50}`
`Get-NetTCPConnection | Where-Object {$_.State -eq “Established”}`
`wevtutil qe Security /f:text /c:50`
`reg query “HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run”`
Step-by-step guide:
- The first PowerShell command gets all processes and filters for those using more than 50% CPU, a potential indicator of crypto-mining malware.
– `Get-NetTCPConnection` lists all active TCP connections; filtering for “Established” shows current communication channels to potentially malicious C2 servers.
– `wevtutil` is the command-line utility for the Windows Event Log. The example queries (qe) the Security log, formats output as text (/f:text), and returns 50 events (/c:50). - The `reg query` command displays the contents of the common “Run” key, which is often abused by malware for persistence.
4. Log Analysis with grep and jq
Security analysts spend a significant amount of time sifting through logs. Mastering filtering tools is non-negotiable.
`grep -i “failed” /var/log/auth.log`
`grep -E “([0-9]{1,3}\.){3}[0-9]{1,3}” access.log`
`jq ‘. | {user: .user, action: .event}’ log.json`
`cat http_logs.json | jq ‘select(.status_code == 500)’`
Step-by-step guide:
- The first `grep` command searches the authentication log for any line containing the word “failed” (case-insensitive with
-i), which can reveal brute-force attempts. - The second command uses extended regular expressions (
-E) to find any IP address pattern in a web access log.
– `jq` is a command-line JSON processor. The third command extracts and formats only the “user” and “event” fields from a JSON log entry. - The fourth command uses `jq` to filter a JSON log file, selecting only entries where the `status_code` field equals 500, helping to identify server errors.
5. Vulnerability Scanning with Nmap
Understanding what is on your network is the first step in understanding your attack surface. Nmap is the industry standard for network discovery and security auditing.
`nmap -sS -sV -O 192.168.1.0/24`
`nmap –script vuln 10.0.0.5`
`nmap -p 80,443,22,3389 -sT scanme.nmap.org`
Step-by-step guide:
– `nmap -sS -sV -O` performs a SYN stealth scan (-sS), attempts to determine service/version info (-sV), and performs OS fingerprinting (-O) on the entire 192.168.1.0/24 subnet.
– The `–script vuln` option activates the Nmap Scripting Engine (NSE) to run a suite of scripts that check for known vulnerabilities against the target host.
– The third command specifies a custom set of common ports (-p 80,443,22,3389) and uses a full TCP connect scan (-sT) against a public target.
6. Web Application Security Testing with curl
APIs and web applications are prime targets. Analysts must be able to manually probe these services to understand their behavior and test for common flaws.
`curl -X GET http://example.com/api/v1/users`
`curl -H “X-API-Key: 12345” https://api.test.com/data`
`curl -d “username=admin&password=guess” -X POST http://test.com/login`
Step-by-step guide:
- The first command uses `curl` to send a simple GET request to an API endpoint, which could reveal sensitive data if improperly secured.
- The second command demonstrates adding a custom header (
-H) to the request, which is often required for API authentication. - The third command sends a POST request (
-X POST) with form-encoded data (-d) to a login endpoint, simulating a basic authentication attempt that could be used to test for brute-force vulnerabilities or SQL injection.
7. System Hardening and Integrity Checks
Proactive security is as important as reactive response. These commands help ensure system integrity and configuration.
`find / -type f -perm -o=w -user root 2>/dev/null`
`sudo chmod 600 /etc/shadow`
`sshd -T | grep passwordauthentication`
Step-by-step guide:
- The `find` command searches the entire filesystem (
/) for files that are world-writable (-perm -o=w) and owned by root. This is a common misconfiguration that could be exploited. - The `chmod` command changes the permissions of the critical `/etc/shadow` file (which stores password hashes) to be readable and writable only by root, a basic hardening step.
– `sshd -T` outputs the effective configuration of the SSH server. Piping it to `grep` checks if password authentication is enabled, which should often be disabled in favor of key-based authentication in secure environments.
What Undercode Say:
- The technical bar for entry-level cybersecurity roles is rising, with practical command-line proficiency becoming a baseline expectation.
- Modern SOC and CERT roles demand a hybrid skill set, combining deep system knowledge (Linux/Windows) with network and application security awareness.
The DNSC’s recruitment drive is a microcosm of a global trend: the formalization and professionalization of cybersecurity. No longer a niche IT function, it is a dedicated discipline requiring a specific and verifiable skill set. The commands and techniques outlined are not just academic exercises; they are the daily tools of the trade. Success in a competitive hiring process like this one will hinge on a candidate’s ability to not only list these skills on a resume but also demonstrate their practical application in a high-fidelity environment. The future analyst must be as comfortable in a Bash shell or PowerShell as they are in a web interface.
Prediction:
The specialization seen in this DNSC hiring—splitting roles between national CERTs, sectorial CERTs, and a 24/7 SOC—will become the global standard. This will force cybersecurity training and education to become more granular, moving away from generic “cybersecurity” courses and towards specialized, role-specific technical tracks that prioritize hands-on, command-line driven competencies over theoretical knowledge. The analysts trained and hired in this wave will form the core of national cyber defense capabilities for the next decade.
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IT/Security Reporter URL:
Reported By: Georgedanieldumitru Nr – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
