CWE

Improper Restriction of Names for Files and Other Resources

ID: 641		Date: (C)2012-05-14   (M)2022-10-10
Type: weakness		Status: INCOMPLETE
Abstraction Type: Base

Description

The application constructs the name of a file or other resource using input from an upstream component, but does not restrict or incorrectly restricts the resulting name.

Extended Description

This may produce resultant weaknesses. For instance, if the names of these resources contain scripting characters, it is possible that a script may get executed in the client's browser if the application ever displays the name of the resource on a dynamically generated web page. Alternately, if the resources are consumed by some application parser, a specially crafted name can exploit some vulnerability internal to the parser, potentially resulting in execution of arbitrary code on the server machine. The problems will vary based on the context of usage of such malformed resource names and whether vulnerabilities are present in or assumptions are made by the targeted technology that would make code execution possible.

Enabling Factors for Exploitation
Resource names are controllable by the user.
No sufficient validation of resource names at entry points or before consumption by other processes.
Context where the resources are consumed makes execution of code possible based on the names of the supplied resources.

Likelihood of Exploit: Low

Applicable Platforms
Language Class: All

Time Of Introduction

• Architecture and Design
• Implementation

Common Consequences

Scope	Technical Impact	Notes
Integrity Confidentiality Availability	Execute unauthorized code or commands	Execution of arbitrary code in the context of usage of the resources with dangerous names.
Confidentiality Availability	Read application data DoS: crash / exit / restart	Crash of the consumer code of these resources resulting in information leakage or denial of service.

Detection Methods
None

Potential Mitigations

Phase	Strategy	Description	Effectiveness	Notes
Architecture and Design		Do not allow users to control names of resources used on the server side.
Architecture and Design		Perform white list input validation at entry points and also before consuming the resources. Reject bad file names rather than trying to cleanse them.
Architecture and Design		Make sure that technologies consuming the resources are not vulnerable (e.g. buffer overflow, format string, etc.) in a way that would allow code execution if the name of the resource is malformed.

Relationships

Related CWE	Type	View	Chain
CWE-641 ChildOf CWE-896	Category	CWE-888

Demonstrative Examples
None

White Box Definitions
None

Black Box Definitions
None

Taxynomy Mappings
None

References:
None