Where ethical hacking or penetration testing is concerned, the initial phase is probably most critical and most neglected by novices. It is known as reconnaissance, or simply as recon.

Consider recon as the information collection phase. As a burglar might plan to break into a house by examining windows, doors, alarms, or the owner's schedule, so a penetration tester collects as much information as they can about a target before conducting any active attacks.

In this blog, we will dissect the reconnaissance phase into bite-sized pieces that you'll understand, discuss tools you can utilize, and provide real-world scenarios to make the idea concrete.

Prefer watching instead of reading? Here’s a quick video guide

https://youtu.be/jUiZfbLjAfY?embedable=true

What is Reconnaissance?

Reconnaissance is the attack preparatory phase where a tester gathers information on a target to find possible vulnerabilities. It is no direct damage or attacks, merely data gathering and analysis.

There are two primary forms of reconnaissance:

Passive Recon: No Touch, No Trace

Passive recon is all about collecting information in a covert manner. As you're not touching the target system directly, you're less likely to be seen. Here's what you can do:

WHOIS Lookup

Employ tools such as whois.domaintools.com or Linux's whois command to obtain:

This can provide hints regarding the organization, admins, or possibly internal setup.

DNS Enumeration

Utilize tools such as dig, nslookup, or dnsdumpster.com to:

Google Dorking

Google is not only a search engine, it's an information treasure trove. Utilize special searches such as:

site:openexploit.in intitle:"index of"
site:openexploit.in filetype:pdf

These dorks have the capability to reveal sensitive directories, documents, and configuration files.

Social Media & Employee Details

Platforms such as LinkedIn, Twitter, or Facebook have the ability to reveal:

This assists in social engineering or designing phishing attacks later.

Active Reconnaissance: Knocking on the Door

After passive recon provides you with a picture, active recon assists you in probing further, but this means direct interaction, which can be detected.

Port Scanning

Tools such as Nmap can scan open ports and services:

nmap -sS -Pn -T4 openexploit.in

You may find:

This assists you in discovering attack surfaces such as outdated software or poorly configured ports.

Service Enumeration

Utilize tools such as Nmap scripts, enum4linux, or Nikto to:

Example:

nmap -sV --script vuln openexploit.in

Subdomain Enumeration

Utilize tools such as:

The discovery of hidden subdomains such as dev.openexploit.in or staging.openexploit.in can reveal weak entry points.

Tools You Should Know

The following are some commonly used recon tools with a brief description:

Example Recon

Suppose your target is openexploit.in. Here is a simplified recon workflow:

You haven't launched anything yet, but you now have open ports, running software, employee information, and probable attack vectors.

Why Recon is Important

Skimping on recon is like attempting to pick a lock blindfolded. Here's why it's important:

Legalities and Ethics

Have permission first before carrying out recon. Unauthorized recon, even passive, on live systems may be illegal under cybersecurity legislations such as the Computer Fraud and Abuse Act (CFAA) or India's IT Act.

Limit yourself to bug bounty programs, test environments such as TryHackMe/Hack The Box, or internal sanctioned engagements.

Last Words

Recon is where great pentesters turn excellent. The better you recon, the wiser your attacks, and the greater value you provide to clients or businesses.

Before you begin bashing doors and taking advantage of services, breathe. Act like a detective, not a battering ram.

If you're studying penetration testing, make reconnaissance your buddy. Because in cyber war, knowledge isn't simply power, it's the first blow.