Session Security And Buffer Overflows In Web Applications

In the first installment of this series we introduced the reader to web application security issues and stressed the significance of input validation. In the second installment, several categories of web application vulnerabilities were discussed and methods for locating these vulnerabilities . . . In the first installment of this series we introduced the reader to web application security issues and stressed the significance of input validation. In the second installment, several categories of web application vulnerabilities were discussed and methods for locating these vulnerabilities were outlined. In this third and final article we will be investigating session security issues and cookies, buffer overflows and logic flaws, and providing links to further resources for the web application penetration tester.

Cookies are a mechanism for maintaining persistent data on the client side of a HTTP exchange. They are not part of the HTTP specification, but are a de-facto industry standard based on a specification issued by Netscape. Cookies involve the use of HTTP header responses to set values on the client side, and in client requests to provide these values back to the server side. The value is set using a 'Set-Cookie' header and returned using a 'Cookie' header. Take the following example of an exchange of cookies. The client requests a resource, and receives in the headers of the response:

Set-Cookie: PASSWORD=g0d; path=/; expires=Friday, 20-Jul-03 23:23:23 GMT

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