The 5 Command Line Hacks Every Cybersecurity Pro Uses (But Won’t Talk About)

By /

Listen to this Post

Featured Image

Introduction:

In the high-stakes world of cybersecurity, efficiency and precision are paramount. While flashy GUI tools have their place, elite professionals leverage the raw power of the command line to automate tasks, dissect vulnerabilities, and harden systems at scale. This article pulls back the curtain on the essential, often-overlooked command-line techniques that form the backbone of real-world security operations.

Learning Objectives:

  • Master advanced command-line techniques for log analysis and threat hunting.
  • Automate critical security hardening tasks across Windows and Linux systems.
  • Utilize built-in tools for network reconnaissance and vulnerability assessment.

You Should Know:

  1. Mastering Log Analysis with grep, awk, and `sort`
    Security investigations often begin in the logs. These commands help you cut through the noise to find the signal.

    Find failed SSH login attempts, extract the IP addresses, and count them
grep "Failed password" /var/log/auth.log | awk '{print $11}' | sort | uniq -c | sort -nr

Analyze Windows Security Event Log for specific Event ID 4625 (failed logon)
Get-WinEvent -FilterHashtable @{LogName='Security'; ID=4625} | ForEach-Object { $_.Properties[bash].Value } | Group-Object | Sort-Object Count -Descending

Step-by-step guide:

  1. The `grep` command filters the log file for only lines containing “Failed password”.
    2. `awk ‘{print $11}’` extracts the 11th field (typically the IP address) from each line.
  2. The first `sort` command orders the IPs alphabetically, preparing them for uniq.
    4. `uniq -c` counts the number of occurrences of each unique IP.
  3. The final `sort -nr` sorts the output numerically and in reverse order, showing the most frequent offenders first.

2. Network Reconnaissance with Built-in Tools

Before deploying external tools, you can perform quick, stealthy recon using native utilities.

 Linux: Discover live hosts on the local network using arp-scan (may require installation)
sudo arp-scan --localnet

Windows: Enumerate network shares and sessions (great for internal pen tests)
net view \target-computer /ALL
net session

Cross-platform: Test for open ports on a remote system
Test-NetConnection -ComputerName 192.168.1.50 -Port 445  PowerShell
nc -zv 192.168.1.50 1-1000 2>&1 | grep succeeded  Linux netcat

Step-by-step guide:

1. `arp-scan` sends ARP packets to all hosts on the local network and lists which IPs respond, building a live host map.
2. `net view` queries a target Windows machine to list all its shared resources, crucial for identifying misconfigurations.
3. `Test-NetConnection` or `nc` (netcat) can probe a range of ports to identify running services without triggering aggressive IDS alerts, as they use standard SYN or connect requests.

3. Automating System Hardening Scripts

Automation is key to consistent security. These scripts check for and remediate common misconfigurations.

 Linux: Script to check for world-writable files and remove permissions
find / -xdev -type f -perm -0002 -exec ls -l {} \; 2>/dev/null
find / -xdev -type f -perm -0002 -exec chmod o-w {} \; 2>/dev/null

Windows PowerShell: Enforce LSA Protection to prevent credential dumping
$registryPath = "HKLM:\SYSTEM\CurrentControlSet\Control\Lsa"
$name = "RunAsPPL"
$value = "1"
if ((Get-ItemProperty -Path $registryPath -Name $name -ErrorAction SilentlyContinue) -ne $value) {
Set-ItemProperty -Path $registryPath -Name $name -Value $value -Type DWORD
Write-Host "LSA Protection enabled. Reboot required."
}

Step-by-step guide:

  1. The Linux `find` command searches the entire filesystem (/) for files (-type f) with the ‘other-writable’ bit set (-perm -0002), a significant security risk.
  2. The second command finds the same files and removes the world-writable permission (chmod o-w).
  3. The PowerShell script checks the Windows registry for a key that enables LSA Protection, a critical defense against tools like Mimikatz. If it’s not set correctly, the script configures it and alerts the user that a reboot is needed.

4. API Security Testing with `curl`

`curl` is an indispensable tool for manually testing API endpoints for common vulnerabilities like injection flaws or broken access control.

 Test for SQL Injection (SQLi) in a POST request
curl -X POST https://api.target.com/v1/login -H "Content-Type: application/json" -d '{"username":"admin'\"","password":"test"}'

Test for IDOR (Insecure Direct Object Reference) by changing the user_id parameter
curl -H "Authorization: Bearer <YOUR_TOKEN>" https://api.target.com/v1/user/123/account

Fuzz parameters for potential SSRF (Server-Side Request Forgery)
curl -X POST https://api.target.com/v1/fetch -d '{"url":"http://169.254.169.254/latest/meta-data/"}'

Step-by-step guide:

  1. The first command sends a malformed username value (admin'\") to see if the application returns a database error, indicating a potential SQLi flaw.
  2. The second command attempts to access a resource for `user/123` after authenticating. If successful, it may indicate an IDOR vulnerability where the application doesn’t correctly verify the user is authorized to access that data.
  3. The third command tries to trick the server into making a request to an internal AWS metadata endpoint, a classic test for SSRF.

5. Cloud Infrastructure Hardening Checks

Misconfigured cloud storage is a leading cause of data breaches. Use CLI tools to audit your environments continuously.

 AWS CLI: Scan all S3 buckets for public read access
aws s3api list-buckets --query "Buckets[].Name" --output text | xargs -I {} aws s3api get-bucket-acl --bucket {} --output text | grep -A2 "Grantee: URI=\"http://acs.amazonaws.com/groups/global/AllUsers\""

Azure CLI: List all storage accounts with public blob access enabled
az storage account list --query "[?allowBlobPublicAccess].{Name:name, PublicAccess:allowBlobPublicAccess}"

GCloud CLI: Check if a Cloud Storage bucket is publicly accessible
gsutil iam get gs://my-bucket | grep allUsers

Step-by-step guide:

  1. The AWS command first lists all S3 bucket names, then pipes that list to check each bucket’s ACL for the presence of the `AllUsers` group grant, which indicates public access.
  2. The Azure CLI command queries for all storage accounts and filters the results to only show accounts where the `allowBlobPublicAccess` property is true.
  3. The GCloud command checks the IAM policy of a specific bucket for the `allUsers` principal, which would confirm it is public. These checks should be integrated into CI/CD pipelines for ongoing compliance.

What Undercode Say:

  • The command line is not obsolete; it is the ultimate precision instrument for cybersecurity. Mastery of CLI tools separates analysts from engineers, enabling automation and deep system introspection that GUIs often hide.
  • The most powerful toolchain is the one already on the system. Native utilities like net, find, awk, and PowerShell cmdlets are invaluable for assessments on restricted environments where downloading external tools is impossible.

The reliance on complex, interconnected systems and APIs only increases the attack surface. The professionals who can quickly script their way through log analysis, automate hardening, and probe for vulnerabilities with built-in tools will be the ones effectively reducing risk. The future of defense is not just in buying new tools, but in deeply understanding the layers of the stack through the fundamental interface that controls it all: the command line.

🎯Let’s Practice For Free:

IT/Security Reporter URL:

Reported By: https://lnkd.in/p/dqMQkZYy – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

🔐JOIN OUR CYBER WORLD [ CVE News • HackMonitor • UndercodeNews ]

💬 Whatsapp | 💬 Telegram

📢 Follow UndercodeTesting & Stay Tuned:

𝕏 formerly Twitter 🐦 | @ Threads | 🔗 Linkedin | 🦋BlueSky

Related Posts: