Suhosin is a security product released by Hardened-PHP to secure your PHP application. Hardened-PHP is founded by Stefan Esser, Christopher Kunz and Peter Prochaska from Germany with the primary goal to help php web developers, development organization to secure PHP web application. They also provide searvice to find out security holes in your php applicatn by examining application code.
Suhosin comes with two component that can work separately or in collboration. The first component called Suhosin patch that help you to secure your application from some low-lever vulnerabilities like bufferoverflows. The second component comes as PHP extension that reduce risk of other security flaws.