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Home > CWE List > CWE-428: Unquoted Search Path or Element (4.20)  
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    CWE-428: Unquoted Search Path or Element

    Weakness ID: 428
    Vulnerability Mapping: ALLOWED This CWE ID may be used to map to real-world vulnerabilities
    Abstraction: Base Base - 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 uses a search path that contains an unquoted element, in which the element contains whitespace or other separators. This can cause the product to access resources in a parent path.
    + Extended Description
    If a malicious individual has access to the file system, it is possible to elevate privileges by inserting such a file as "C:\Program.exe" to be run by a privileged program making use of WinExec.
    + Common Consequences
    Section HelpThis 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: Confidentiality, Integrity, Availability

    + Potential Mitigations
    Phase(s) Mitigation

    Implementation
    Properly quote the full search path before executing a program on the system.

    Implementation

    Strategy: Input Validation

    Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.

    When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."

    Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

    Implementation

    Strategy: Input Validation

    Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
    + Relationships
    Section Help 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 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. 668 Exposure of Resource to Wrong Sphere
    PeerOf Base Base - 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. 426 Untrusted Search Path
    + Relevant to the view "Software Development" (View-699)
    Nature Type ID Name
    MemberOf Category Category - a CWE entry that contains a set of other entries that share a common characteristic. 1219 File Handling Issues
    + Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (View-1003)
    Nature Type ID Name
    ChildOf Class 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. 668 Exposure of Resource to Wrong Sphere
    + Modes Of Introduction
    Section HelpThe 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
    Implementation
    + Applicable Platforms
    Section HelpThis 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)

    Operating Systems

    Windows NT (Sometimes Prevalent)

    macOS (Rarely Prevalent)

    + Demonstrative Examples

    Example 1


    The following example demonstrates the weakness.

    (bad code)
    Example Language: C 
    UINT errCode = WinExec( "C:\\Program Files\\Foo\\Bar", SW_SHOW );


    + Selected Observed Examples

    Note: this is a curated list of examples for users to understand the variety of ways in which this weakness can be introduced. It is not a complete list of all CVEs that are related to this CWE entry.

    Reference Description
    Small handful of others. Program doesn't quote the "C:\Program Files\" path when calling a program to be executed - or any other path with a directory or file whose name contains a space - so attacker can put a malicious program.exe into C:.
    CreateProcess() and CreateProcessAsUser() can be misused by applications to allow "program.exe" style attacks in C:
    Applies to "Common Files" folder, with a malicious common.exe, instead of "Program Files"/program.exe.
    + Weakness Ordinalities
    Ordinality Description
    Primary
    (where the weakness exists independent of other weaknesses)
    + Functional Areas
    • Program Invocation
    + Memberships
    Section HelpThis 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 CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 981 SFP Secondary Cluster: Path Traversal
    MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1403 Comprehensive Categorization: Exposed Resource
    + Vulnerability Mapping Notes
    Usage ALLOWED
    (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.
    + Notes

    Applicable Platform

    This weakness could apply to any OS that supports spaces in filenames, especially any OS that make it easy for a user to insert spaces into filenames or folders, such as Windows. While spaces are technically supported in Unix, the practice is generally avoided. .

    Maintenance

    This weakness primarily involves the lack of quoting, which is not explicitly stated as a part of CWE-116. CWE-116 also describes output in light of structured messages, but the generation of a filename or search path (as in this weakness) might not be considered a structured message.

    An additional complication is the relationship to control spheres. Unlike untrusted search path (CWE-426), which inherently involves control over the definition of a control sphere, this entry concerns a fixed control sphere in which some part of the sphere may be under attacker control. This is not a clean fit under CWE-668 or CWE-610, which suggests that the control sphere model needs enhancement or clarification.

    + Taxonomy Mappings
    Mapped Taxonomy Name Node ID Fit Mapped Node Name
    PLOVER Unquoted Search Path or Element
    + References
    [REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 11, "Process Loading", Page 654. 1st Edition. Addison Wesley. 2006.
    + Content History
    + Submissions
    Submission Date Submitter Organization
    2006-07-19
    (CWE Draft 3, 2006-07-19)     		PLOVER
    + Modifications
    Modification Date Modifier Organization
    2025-12-11
    (CWE 4.19, 2025-12-11)     		CWE Content Team MITRE
    updated Weakness_Ordinalities
    2023-06-29
    (CWE 4.12, 2023-06-29)     		CWE Content Team MITRE
    updated Mapping_Notes
    2023-04-27
    (CWE 4.11, 2023-04-27)     		CWE Content Team MITRE
    updated Relationships
    2022-04-28
    (CWE 4.7, 2022-04-28)     		CWE Content Team MITRE
    updated Research_Gaps
    2020-06-25
    (CWE 4.1, 2020-06-25)     		CWE Content Team MITRE
    updated Potential_Mitigations
    2020-02-24
    (CWE 4.0, 2020-02-24)     		CWE Content Team MITRE
    updated Potential_Mitigations, Relationships
    2019-06-20
    (CWE 3.3, 2019-06-20)     		CWE Content Team MITRE
    updated Related_Attack_Patterns, Relationships
    2019-01-03
    (CWE 3.2, 2019-01-03)     		CWE Content Team MITRE
    updated Applicable_Platforms, Related_Attack_Patterns
    2018-03-27
    (CWE 3.1, 2018-03-27)     		CWE Content Team MITRE
    updated Relationships
    2017-11-08
    (CWE 3.0, 2017-11-08)     		CWE Content Team MITRE
    updated Applicable_Platforms, Demonstrative_Examples
    2015-12-07
    (CWE 2.9, 2015-12-07)     		CWE Content Team MITRE
    updated Relationships
    2014-07-30
    (CWE 2.8, 2014-07-31)     		CWE Content Team MITRE
    updated Relationships
    2012-10-30
    (CWE 2.3, 2012-10-30)     		CWE Content Team MITRE
    updated Potential_Mitigations
    2012-05-11
    (CWE 2.2, 2012-05-15)     		CWE Content Team MITRE
    updated References, Relationships
    2011-06-01
    (CWE 1.13, 2011-06-01)     		CWE Content Team MITRE
    updated Common_Consequences
    2011-03-29
    (CWE 1.12, 2011-03-30)     		CWE Content Team MITRE
    updated Potential_Mitigations
    2010-06-21
    (CWE 1.9, 2010-06-21)     		CWE Content Team MITRE
    updated Other_Notes
    2009-07-27
    (CWE 1.5, 2009-07-27)     		CWE Content Team MITRE
    updated Applicable_Platforms, Description, Maintenance_Notes, Other_Notes, Potential_Mitigations, Relationships
    2008-09-08
    (CWE 1.0, 2008-09-09)     		CWE Content Team MITRE
    updated Relationships, Other_Notes, Taxonomy_Mappings
    2008-07-01
    (CWE 1.0, 2008-09-09)     		Eric Dalci Cigital
    updated Potential_Mitigations, Time_of_Introduction
    Page Last Updated: April 30, 2026
     

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