Security Bypass

This document covers basic techniques to bypass security mechanisms in Linux systems during penetration testing engagements within the OSCP scope.

Table of Contents

Firewall Evasion

Alternative Ports

Common services often run on non-standard ports to bypass firewall restrictions:

# SSH on non-standard port
ssh user@target -p 2222

# HTTP/HTTPS on alternative ports
curl -vk https://target:8443
nc -nvz target 8080

Source Port Manipulation

Many firewalls allow traffic from trusted ports:

Log Evasion

Basic Log Cleanup

Simple techniques to reduce traces in system logs:

File Timestomping

Modify file timestamps to match surrounding files:

Traffic Tunneling

SSH Tunneling

Basic SSH tunneling techniques:

Proxychains

Using proxychains to tunnel traffic through a proxy:

Port Redirection

Simple Port Redirection

Using netcat for basic port redirection:

Using Socat

Socat is more stable for port forwarding:

Additional Resources

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