Essential Cybersecurity Commands and Techniques for AppSec Engineers

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Introduction

Application Security (AppSec) Engineers play a critical role in safeguarding software from vulnerabilities. Whether you’re a seasoned professional or aspiring to enter the field, mastering key commands and techniques is essential. This guide covers verified Linux/Windows commands, API security, and cloud hardening to enhance your security posture.

Learning Objectives

  • Execute critical Linux/Windows security commands for vulnerability assessment.
  • Harden cloud environments using AWS/Azure security best practices.
  • Detect and mitigate common API security risks.

You Should Know

1. Linux Security: Detecting Open Ports with `netstat`

Command:

netstat -tuln | grep LISTEN

What It Does:

Lists all active listening ports, helping identify unauthorized services.

Step-by-Step Guide:

1. Open a terminal.

2. Run `netstat -tuln` to display TCP/UDP ports.

  1. Pipe (|) the output to `grep LISTEN` to filter active services.

4. Investigate unfamiliar ports using `lsof -i :

`.</h2>

<ol>
<li>Windows Security: Checking User Privileges with `whoami` </li>
</ol>

<h2 style="color: yellow;">Command:</h2>

[bash]
whoami /priv

What It Does:

Displays current user privileges, critical for identifying over-permissioned accounts.

Step-by-Step Guide:

1. Open PowerShell as Administrator.

2. Run `whoami /priv` to list privileges.

  1. Verify if “SeDebugPrivilege” or “SeBackupPrivilege” is enabled unnecessarily.
    1. API Security: Testing for Broken Object-Level Authorization (BOLA)

Tool: Burp Suite

Steps:

1. Intercept an API request (e.g., `GET /api/user/123`).

  1. Change the user ID (e.g., `123` → 124) and resend.
  2. If data leaks, the API is vulnerable to BOLA.

Mitigation:

  • Implement proper session validation.
  • Use UUIDs instead of incremental IDs.
    1. Cloud Hardening: AWS S3 Bucket Permissions Audit

AWS CLI Command:

aws s3api get-bucket-acl --bucket [bash]

What It Does:

Checks if an S3 bucket allows public access.

Step-by-Step Guide:

1. Install AWS CLI and configure credentials.

2. Run the command, replacing `

`.</h2>

<h2 style="color: yellow;">3. Look for `"Permission": "READ"` for `"Grantee": "Everyone"`.</h2>

<h2 style="color: yellow;">4. Restrict via:</h2>

[bash]
aws s3api put-bucket-acl --bucket [bash] --acl private
  1. Vulnerability Exploitation: Testing for SQLi with `sqlmap`

Command:

sqlmap -u "https://example.com/login?user=1" --dbs

What It Does:

Automates SQL injection testing to extract database names.

Step-by-Step Guide:

1. Install `sqlmap` (`pip install sqlmap`).

2. Target a vulnerable parameter (e.g., `?user=1`).

3. Use `–dbs` to list databases.

4. Patch vulnerabilities with parameterized queries.

What Undercode Say

  • Key Takeaway 1: Proactive port monitoring prevents backdoor attacks.
  • Key Takeaway 2: Least-privilege principles minimize breach impact.

Analysis:

AppSec engineers must blend offensive testing (e.g., sqlmap) with defensive hardening (e.g., AWS S3 ACLs). As APIs and cloud adoption grow, mastering these commands ensures robust security. Future trends will demand AI-driven threat detection, but foundational CLI skills remain irreplaceable.

Prediction:

By 2026, 60% of breaches will stem from misconfigured APIs/cloud storage. Engineers who automate security audits (e.g., AWS CLI, netstat) will lead in mitigating these risks.

IT/Security Reporter URL:

Reported By: Activity 7344498479357902848 – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

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