1. A method for detecting at least one security vulnerability, comprising: providing test instructions for an application being a web application or a client server application; adding test code to a code segment of said application according to said test instructions; sending at least one message to said application according to said test instructions at runtime thereof; monitoring test information pertaining to at least one reaction of said application to said at least one message during an execution of said test code; performing an analysis of said at least one reaction; and detecting a presence or an absence of at least one security vulnerability according to said analysis.