Layer 3 Attacks

Layer 3 Attacks - Network Layer Exploitation

Layer 3 attacks target the Internet Protocol (IP) layer, exploiting routing, addressing, and packet forwarding mechanisms to compromise network integrity, availability, and security. These attacks manipulate fundamental network infrastructure components that enable internet communications.

Understanding Layer 3 Vulnerabilities

Protocol Trust Issues: Layer 3 protocols like IP, ICMP, and routing protocols were designed for functionality rather than security, creating inherent trust relationships that attackers can exploit.

Global Impact: Unlike Layer 2 attacks limited to broadcast domains, Layer 3 attacks can traverse routers and affect entire network infrastructures across different segments.

Infrastructure Targeting: These attacks often target core network services including routing tables, IP allocation systems, and packet forwarding mechanisms.

Attack Categories Overview

IP-Based Attacks

  • IP Spoofing: Forge source IP addresses to impersonate legitimate systems
  • Source Routing: Manipulate packet routing paths to bypass security controls
  • IP Fragmentation: Exploit packet reassembly mechanisms for evasion and DoS

Control Protocol Exploitation

  • ICMP Attacks: Abuse Internet Control Message Protocol for reconnaissance and DoS
  • Routing Manipulation: Compromise routing protocols to redirect or intercept traffic
  • Address Resolution: Exploit IP allocation and management systems

Next-Generation Protocols

  • IPv6 Vulnerabilities: Exploit dual-stack configurations and IPv6-specific weaknesses
  • Transition Mechanism Abuse: Target IPv4-to-IPv6 transition technologies

Professional Context

Layer 3 attacks are fundamental to understanding network security because they:

  • Test Network Segmentation: Verify that routing controls properly isolate network segments
  • Validate Security Controls: Assess effectiveness of firewalls, ACLs, and routing security
  • Identify Infrastructure Weaknesses: Reveal misconfigurations in core network services
  • Enable Advanced Attacks: Provide positioning for application-layer exploitation

Module Structure

This module covers six critical Layer 3 attack categories:

IP Spoofing

Source address manipulation and routing attacks for impersonation and bypass techniques.

ICMP Attacks

Internet Control Message Protocol exploitation for reconnaissance, redirection, and denial of service.

Routing Protocol Attacks

Dynamic routing protocol manipulation including RIP, OSPF, and BGP fundamentals.

Fragmentation Attacks

IP packet fragmentation and reassembly exploitation for evasion and resource exhaustion.

IP Address Exhaustion

IP allocation system attacks and address space exhaustion techniques.

IPv6 Attacks

Next-generation protocol vulnerabilities and dual-stack configuration exploitation.

Layer 3 attacks form the foundation of network penetration testing, providing essential skills for assessing and securing network infrastructure at the protocol level.