OWASP
FreeWeb security standards and the Top 10.
Cybersecurity
PentestingWeb and network pentesting tools, knowledge bases and labs to find and fix security issues.
Only test systems you own or have written permission for — unauthorized testing is illegal in most countries.
Free web security labs.
The standard web pentesting tool.
Kali Linux
FreeLinux distribution for pentesting.
Pentesting framework.
Nmap
FreeNetwork scanning and port discovery.
Wireshark
FreePacket capture analysis.
HackTricks
FreePentesting techniques wiki.
Online pentesting labs.
Beginner-friendly security learning platform.
VulnHub
FreeDownloadable vulnerable VMs.