COMMON WEAKNESS ENUMERATIONDraft

CWE-567

Unsynchronized Access to Shared Data in a Multithreaded Context

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

Soyutlama

Base

Yapı

Simple

Sömürü İhtimali

Medium

Problemi anla

Problem nedir?

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

Genişletilmiş açıklama

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.

Kök neden

Problem nasıl ve ne zaman oluşur?

Yaşam döngüsü evresi

Implementation

Risk

Başarılı sömürü neye yol açar?

Read Application DataModify Application DataDoS: InstabilityDoS: Crash, Exit, or Restart

Etkilenen güvenlik alanları: Confidentiality, Integrity, Availability

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.

Savunma

Nasıl önlenir ve çözülür?

Implementation

Uygulama aşaması savunması

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

Doğrulama

Nasıl tespit edilir?

Automated Static Analysis

High
Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)