ABSTRACT

A cookie with an overly broad path can be accessed through other applications on the same domain.

EXPLANATION

Developers often set cookies to be the root context path "/", however, doing so exposes the cookie to all web applications on the same domain name. Since cookies often carry sensitive information such as session identifiers, sharing cookies across applications can lead a vulnerability in one application to cause a compromise in another.

Example:
Imagine you have a forum application deployed at http://communitypages.example.com/MyForum and the application sets a session ID cookie with path "/" when users log in to the forum.

For example:


HttpCookie cookie = new HttpCookie("sessionID", sessionID);
cookie.Path = "/";


Suppose an attacker creates another application at http://communitypages.example.com/EvilSite and posts a link to this site on the forum. When a user of the forum clicks on the link, his browser will send the cookie set by /MyForum to the application running at /EvilSite. By stealing the session ID, the attacker is able to compromise the account of any forum user that browsed to /EvilSite.

In addition to reading a cookie, it might be possible for attackers to perform a Cookie Poisoning attack by using /EvilSite to create its own overly broad cookie that overwrites the cookie from /MyForum.

REFERENCES

[1] Standards Mapping - OWASP Top 10 2004 - (OWASP 2004) A10 Insecure Configuration Management

[2] Standards Mapping - OWASP Top 10 2007 - (OWASP 2007) A6 Information Leakage and Improper Error Handling

[3] Standards Mapping - OWASP Top 10 2010 - (OWASP 2010) A6 Security Misconfiguration

[4] Standards Mapping - FIPS200 - (FISMA) CM

[5] Standards Mapping - Web Application Security Consortium 24 + 2 - (WASC 24 + 2) Information Leakage

[6] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 - (PCI 1.1) Requirement 6.5.10

[7] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 - (PCI 1.2) Requirement 6.5.7

[8] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 - (PCI 2.0) Requirement 6.5.8