42 • INTERMEDIATE • SYN Flood and TCP Attacks
Half-Open Connection Exploit
This lesson covers Half-Open Connection Exploit in the context of SYN Flood and TCP Attacks. Topics include: sysctl net.ipv4.tcp_max_syn_backlog, nginx limit_req_zone, tcpdump port 53. Educational and defensive use only.
Code Example
// SYN cookie (kernel)
// Encode seq in cookie, verify on ACK
// No state until connection establishedCommands & References
- sysctl net.ipv4.tcp_max_syn_backlog
- nginx limit_req_zone
- tcpdump port 53
Lab Steps
- Set up your lab: sysctl net.ipv4.tcp_max_syn_backlog
- Understand the attack or defense mechanism.
- Apply in a controlled environment.
- Document findings.
- Consider mitigation strategies.
Exercises
- Research recent DDoS incidents.
- Design a defense for a sample scenario.
- Review legal implications.
- Practice incident response.