Master network security techniques including port scanning, DNS analysis, subdomain discovery, and vulnerability assessment
Port scanning is the process of checking which ports are open on a target system. It's essential for network security assessment and penetration testing.
| Port | Service | Protocol | Security Risk |
|---|---|---|---|
| 21 | FTP | TCP | High |
| 22 | SSH | TCP | Medium |
| 23 | Telnet | TCP | High |
| 80 | HTTP | TCP | Medium |
| 443 | HTTPS | TCP | Low |
| 3389 | RDP | TCP | High |
Establishes full TCP connection. Most reliable but easily detected.
Sends SYN packets without completing handshake. Stealthier than connect scan.
Scans UDP ports. Slower and less reliable than TCP scans.
Sends FIN packets. Can bypass some firewalls.
DNS (Domain Name System) analysis helps identify potential security issues, misconfigurations, and attack vectors in domain infrastructure.
Map domain names to IPv4 addresses. Essential for website accessibility.
Map domain names to IPv6 addresses. Future-proofing for IPv6 adoption.
Specify mail servers for the domain. Critical for email functionality.
Store text information. Often used for SPF, DKIM, and DMARC records.
Create aliases for domain names. Can be security risk if misconfigured.
Malicious redirection of DNS queries to attacker-controlled servers.
Fake DNS responses to redirect traffic to malicious sites.
Unauthorized zone transfers can reveal internal network structure.
Exploiting abandoned subdomains to gain control of domains.
Subdomain discovery is crucial for understanding the attack surface of a domain. It helps identify all publicly accessible services and potential entry points.
Querying DNS servers for subdomain records using various techniques like zone transfers and wildcard queries.
Searching public certificate logs to find subdomains that have SSL certificates issued.
Using Google dorks and other search engine queries to find indexed subdomains.
Systematically testing common subdomain names against the target domain.
Unencrypted remote access, easily intercepted
Credentials transmitted in plain text
Remote desktop without proper security
Unencrypted web traffic
Poor SSH configuration or weak keys
MySQL (3306), PostgreSQL (5432) exposed
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Scan open ports on any IP address or hostname to identify potential security risks.
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