Testing Application vulnerability tools

[WALI <hkhasgiwale () gmail com>]

I have a team of software developers involved in writing code for HR 
management application. They have put the first module payroll online but 
everyday, we get reports of users getting access to areas they shouldn't. 
The software team is involved in continues debugging and patching.

Is there a tool I can use to do software code review (.NET)

I know it's also design issue but there should be a way I can at least 
check the front end (http) interface for common vulnerabilities?