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.

Primary

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.

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.

Medium

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

Access Control
Non-Repudiation
Gain Privileges or Assume Identity
Hide Activities
If privileges are not dropped, in some cases the system may record actions as the user which is being impersonated rather than the impersonator.

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.)
High

Architecture and Design
Separation of Privilege

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
Check the results of all functions that return a value and verify that the value is expected.
High
Checking the return value of the function will typically be sufficient, however beware of race conditions (CWE-362) in a concurrent environment.

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.

This code attempts to take on the privileges of a user before creating a file, thus avoiding performing the action with unnecessarily high privileges:

bool DoSecureStuff(HANDLE hPipe) {bool fDataWritten = false;ImpersonateNamedPipeClient(hPipe);HANDLE hFile = CreateFile(...);/../RevertToSelf()/../}

The call to ImpersonateNamedPipeClient may fail, but the return value is not checked. If the call fails, the code may execute with higher privileges than intended. In this case, an attacker could exploit this behavior to write a file to a location that the attacker does not have access to.

CVE-2006-4447
Program does not check return value when invoking functions to drop privileges, which could leave users with higher privileges than expected by forcing those functions to fail.
https://www.cve.org/CVERecord?id=CVE-2006-4447

CVE-2006-2916
Program does not check return value when invoking functions to drop privileges, which could leave users with higher privileges than expected by forcing those functions to fail.
https://www.cve.org/CVERecord?id=CVE-2006-2916

System Process

Failure to check whether privileges were dropped successfully

POS37-C
Ensure that privilege relinquishment is successful
Exact

SFP4
Unchecked Status Condition

Allowed
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.
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.

CLASP
2006-07-19
Draft 3
2006-07-19

Eric Dalci
Cigital
2008-07-01
updated Time_of_Introduction

CWE Content Team
MITRE
2008-09-08
updated Common_Consequences, Description, Modes_of_Introduction, Relationships, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities

CWE Content Team
MITRE
2008-11-24
updated Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2009-03-10
updated Description, Name, Relationships

CWE Content Team
MITRE
2009-05-27
updated Name

CWE Content Team
MITRE
2011-06-01
updated Common_Consequences

CWE Content Team
MITRE
2012-05-11
updated Observed_Examples, Relationships

CWE Content Team
MITRE
2012-10-30
updated Demonstrative_Examples, Potential_Mitigations

CWE Content Team
MITRE
2014-06-23
updated Background_Details, Other_Notes, Potential_Mitigations

CWE Content Team
MITRE
2014-07-30
updated Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2017-11-08
updated Applicable_Platforms, Causal_Nature, Demonstrative_Examples, Modes_of_Introduction, Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2019-01-03
updated Relationships

CWE Content Team
MITRE
2019-06-20
updated Relationships

CWE Content Team
MITRE
2020-02-24
updated References, Relationships, Time_of_Introduction

CWE Content Team
MITRE
2020-12-10
updated Potential_Mitigations

CWE Content Team
MITRE
2023-01-31
updated Description

CWE Content Team
MITRE
2023-04-27
updated Detection_Factors, Relationships, Time_of_Introduction

CWE Content Team
MITRE
2023-06-29
updated Mapping_Notes

Failure to Check Whether Privileges Were Dropped Successfully
Improper Check for Successfully Dropped Privileges