CWE-641: Improper Restriction of Names for Files and Other Resources
Weakness ID: 641
Vulnerability Mapping:ALLOWEDThis CWE ID may be used to map to real-world vulnerabilities Abstraction:
BaseBase - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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Description
The product constructs the name of a file or other resource using input from an upstream component, but it 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.
Common Consequences
This table specifies different individual consequences
associated with the weakness. The Scope identifies the application security area that is
violated, while the Impact describes the negative technical impact that arises if an
adversary succeeds in exploiting this weakness. The Likelihood provides information about
how likely the specific consequence is expected to be seen relative to the other
consequences in the list. For example, there may be high likelihood that a weakness will be
exploited to achieve a certain impact, but a low likelihood that it will be exploited to
achieve a different impact.
Impact
Details
Execute Unauthorized Code or Commands
Scope: Integrity, Confidentiality, Availability
Execution of arbitrary code in the context of usage of the resources with dangerous names.
Read Application Data; DoS: Crash, Exit, or Restart
Scope: Confidentiality, Availability
Crash of the consumer code of these resources resulting in information leakage or denial of service.
Potential Mitigations
Phase(s)
Mitigation
Architecture and Design
Do not allow users to control names of resources used on the server side.
Architecture and Design
Perform allowlist 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
This table shows the weaknesses and high level categories that are related to this
weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to
similar items that may exist at higher and lower levels of abstraction. In addition,
relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user
may want to explore.
Relevant to the view "Research Concepts" (View-1000)
Nature
Type
ID
Name
ChildOf
Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.
The different Modes of Introduction provide information
about how and when this
weakness may be introduced. The Phase identifies a point in the life cycle at which
introduction
may occur, while the Note provides a typical scenario related to introduction during the
given
phase.
Phase
Note
Architecture and Design
Implementation
REALIZATION: This weakness is caused during implementation of an architectural security tactic.
Applicable Platforms
This listing shows possible areas for which the given
weakness could appear. These
may be for specific named Languages, Operating Systems, Architectures, Paradigms,
Technologies,
or a class of such platforms. The platform is listed along with how frequently the given
weakness appears for that instance.
Languages
Class: Not Language-Specific
(Undetermined Prevalence)
Likelihood Of Exploit
Low
Memberships
This MemberOf Relationships table shows additional CWE Categories and Views that
reference this weakness as a member. This information is often useful in understanding where a
weakness fits within the context of external information sources.
Nature
Type
ID
Name
MemberOf
Category - a CWE entry that contains a set of other entries that share a common characteristic.
(this CWE ID may be used to map to real-world vulnerabilities)
Reason
Acceptable-Use
Rationale
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.
Comments
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.
Description
This table specifies different individual consequences
associated with the weakness. The Scope identifies the application security area that is
violated, while the Impact describes the negative technical impact that arises if an
adversary succeeds in exploiting this weakness. The Likelihood provides information about
how likely the specific consequence is expected to be seen relative to the other
consequences in the list. For example, there may be high likelihood that a weakness will be
exploited to achieve a certain impact, but a low likelihood that it will be exploited to
achieve a different impact.
