Détail du CWE-273

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

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

Informations de base

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.

Modes d'introduction

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.

Plateformes applicables

Langue

Class: Not Language-Specific (Undetermined)

Conséquences courantes

Exemples observés

Mesures d’atténuation potentielles

Phases : Architecture and Design

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.

Phases : Implementation
Check the results of all functions that return a value and verify that the value is expected.
Phases : Implementation
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.

Méthodes de détection

Automated Static Analysis

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.)
Efficacité : High

Notes de cartographie des vulnérabilités

Justification : This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Commentaire : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Références

REF-18

The CLASP Application Security Process
Secure Software, Inc..
https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf

Soumission

Modifications