CWE-488: Exposure of Data Element to Wrong Session

How it's found

Exposure of Data Element to Wrong Session is typically found by tracing untrusted input from where it enters the system to the point where it is used without the check or neutralization this weakness describes, combining manual code review with dynamic testing.

Data can "bleed" from one session to another through member variables of singleton objects, such as Servlets, and objects from a shared pool. In the case of Servlets, developers sometimes do not understand that, unless a Servlet implements the SingleThreadModel interface, the Servlet is a singleton; there is only one instance of the Servlet, and that single instance is used and re-used to handle multiple requests that are processed simultaneously by different threads. A common result is that developers use Servlet member fields in such a way that one user may inadvertently see another user's data. In other words, storing user data in Servlet member fields introduces a data access race condition.

Consequences

• Read Application Data

Mitigations

• Architecture and Design: Protect the application's sessions from information leakage. Make sure that a session's data is not used or visible by other sessions.
• Testing: Use a static analysis tool to scan the code for information leakage vulnerabilities (e.g. Singleton Member Field).
• Architecture and Design: In a multithreading environment, storing user data in Servlet member fields introduces a data access race condition. Do not use member fields to store information in the Servlet.

Where this fits in a TurboPentest engagement

This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.

Frequently asked questions

Related CWEs

• Class weakness
  CWE-668: Exposure of Resource to Wrong Sphere