COMMON WEAKNESS ENUMERATIONIncomplete

CWE-273

Improper Check for Dropped Privileges

The product attempts to drop privileges but does not check or incorrectly checks to see if the drop succeeded.

Soyutlama

Base

Yapı

Simple

Sömürü İhtimali

Medium

Problemi anla

Problem nedir?

The product attempts to drop privileges but does not check or incorrectly checks to see if the drop succeeded.

Genişletilmiş açıklama

If the drop fails, the product will continue to run with the raised privileges, which might provide additional access to unprivileged users.

Kök neden

Problem nasıl ve ne zaman oluşur?

Yaşam döngüsü evresi

Implementation

REALIZATION: This weakness is caused during implementation of an architectural security tactic. This issue is likely to occur in restrictive environments in which the operating system or application provides fine-grained control over privilege management.
In Windows based environments that have access control, impersonation is used so that access checks can be performed on a client identity by a server with higher privileges. By impersonating the client, the server is restricted to client-level security -- although in different threads it may have much higher privileges.

Risk

Başarılı sömürü neye yol açar?

Gain Privileges or Assume Identity

Etkilenen güvenlik alanları: Access Control

If privileges are not dropped, neither are access rights of the user. Often these rights can be prevented from being dropped.
Gain Privileges or Assume IdentityHide Activities

Etkilenen güvenlik alanları: Access Control, Non-Repudiation

If privileges are not dropped, in some cases the system may record actions as the user which is being impersonated rather than the impersonator.

Savunma

Nasıl önlenir ve çözülür?

Architecture and Design

Separation of Privilege

Detay
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

Implementation

Uygulama aşaması savunması

Detay
Check the results of all functions that return a value and verify that the value is expected.

Etkinlik: High

Checking the return value of the function will typically be sufficient, however beware of race conditions (CWE-362) in a concurrent environment.

Implementation

Uygulama aşaması savunması

Detay
In Windows, make sure that the process token has the SeImpersonatePrivilege(Microsoft Server 2003). Code that relies on impersonation for security must ensure that the impersonation succeeded, i.e., that a proper privilege demotion happened.

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.)
CWE-273: Common Weakness Enumeration Entry CWE-273 · DayBreach Sözlük · DayBreach