Unsynchronized Access to Shared Data in a Multithreaded Context

Opis

The product does not properly synchronize shared data, such as static variables across threads, which can lead to undefined behavior and unpredictable data changes.

Within servlets, shared static variables are not protected from concurrent access, but servlets are multithreaded. This is a typical programming mistake in J2EE applications, since the multithreading is handled by the framework. When a shared variable can be influenced by an attacker, one thread could wind up modifying the variable to contain data that is not valid for a different thread that is also using the data within the variable.

Note that this weakness is not unique to servlets.

Skutki

• Confidentiality, Integrity, Availability

  Read Application Data; Modify Application Data; DoS: Instability; DoS: Crash, Exit, or Restart

  If the shared variable contains sensitive data, it may be manipulated or displayed in another user session. If this data is used to control the application, its value can be manipulated to cause the application to crash or perform poorly.

Zapobieganie

• Implementation

  Remove the use of static variables used between servlets. If this cannot be avoided, use synchronized access for these variables.

Słabość nadrzędna

• CWE-820 Missing Synchronization
• CWE-662 Improper Synchronization

Może prowadzić do

• CWE-488 Exposure of Data Element to Wrong Session

Kiedy powstaje

• Implementation

Dotyczy

Java