AntiScan.Me

PortSwigger offers tools for web application security, testing, & scanning. Choose from a range of security tools, & identify the very latest vulnerabilities.

Snusbase makes it easy to stay on top of the latest database breaches and makes sure you and your closest stay safe online.

ArgFuscator

BUUCTF 是一个 CTF 竞赛和训练平台，为各位 CTF 选手提供真实赛题在线复现等服务。

Red Team Notes 2.0

Censys empowers security teams with the most comprehensive, accurate, and up-to-date map of the internet to defend attack surfaces and hunt for threats.

Overview of hacking challenge and problem solving sites. - wechall

Online Vulnerability Scanners to Identify Vulnerabilities and Map the Attack Surface. 28 Trusted Security Scanners and Free Network Tools.