CWE-73 Detail

CWE-73

External Control of File Name or Path
Alto
Draft
2006-07-19
00h00 +00:00
2025-12-11
00h00 +00:00
CWE Mitre.org
Notifiche per un CWE specifico
Rimani informato su qualsiasi modifica relativa a un CWE specifico.
Gestione notifiche

Nome: External Control of File Name or Path

The product allows user input to control or influence paths or file names that are used in filesystem operations.

General Informations

Modes Of Introduction

Architecture and Design
Implementation : REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Piattaforme applicabili

Linguaggio

Class: Not Language-Specific (Undetermined)

Sistemi operativi

Class: Unix (Often)
Class: Windows (Often)
Class: macOS (Often)

Conseguenze comuni

Ambito Impatto Probabilità
Integrity
Confidentiality		Read Files or Directories, Modify Files or Directories

Note: The application can operate on unexpected files. Confidentiality is violated when the targeted filename is not directly readable by the attacker.
Integrity
Confidentiality
Availability		Modify Files or Directories, Execute Unauthorized Code or Commands

Note: The application can operate on unexpected files. This may violate integrity if the filename is written to, or if the filename is for a program or other form of executable code.
AvailabilityDoS: Crash, Exit, or Restart, DoS: Resource Consumption (Other)

Note: The application can operate on unexpected files. Availability can be violated if the attacker specifies an unexpected file that the application modifies. Availability can also be affected if the attacker specifies a filename for a large file, or points to a special device or a file that does not have the format that the application expects.

Esempi osservati

Riferimenti Descrizione

CVE-2022-45918

Chain: a learning management tool debugger uses external input to locate previous session logs (CWE-73) and does not properly validate the given path (CWE-20), allowing for filesystem path traversal using "../" sequences (CWE-24)

CVE-2008-5748

Chain: external control of values for user's desired language and theme enables path traversal.

CVE-2008-5764

Chain: external control of user's target language enables remote file inclusion.

Potential Mitigations

Phases : Architecture and Design
When the set of filenames is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames, and reject all other inputs. For example, ID 1 could map to "inbox.txt" and ID 2 could map to "profile.txt". Features such as the ESAPI AccessReferenceMap provide this capability.
Phases : Architecture and Design // Operation
Phases : Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
Phases : Implementation
Phases : Implementation
Use a built-in path canonicalization function (such as realpath() in C) that produces the canonical version of the pathname, which effectively removes ".." sequences and symbolic links (CWE-23, CWE-59).
Phases : Installation // Operation
Use OS-level permissions and run as a low-privileged user to limit the scope of any successful attack.
Phases : Operation // Implementation
If you are using PHP, configure your application so that it does not use register_globals. During implementation, develop your application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.
Phases : Testing
Use tools and techniques that require manual (human) analysis, such as penetration testing, threat modeling, and interactive tools that allow the tester to record and modify an active session. These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules.

Detection Methods

Automated Static Analysis

Note sulla mappatura delle vulnerabilità

Giustificazione : 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.
Commento : 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.

Pattern di attacco correlati

CAPEC-ID Nome del pattern di attacco
CAPEC-13 Subverting Environment Variable Values
The adversary directly or indirectly modifies environment variables used by or controlling the target software. The adversary's goal is to cause the target software to deviate from its expected operation in a manner that benefits the adversary.
CAPEC-267 Leverage Alternate Encoding
An adversary leverages the possibility to encode potentially harmful input or content used by applications such that the applications are ineffective at validating this encoding standard.
CAPEC-64 Using Slashes and URL Encoding Combined to Bypass Validation Logic
This attack targets the encoding of the URL combined with the encoding of the slash characters. An attacker can take advantage of the multiple ways of encoding a URL and abuse the interpretation of the URL. A URL may contain special character that need special syntax handling in order to be interpreted. Special characters are represented using a percentage character followed by two digits representing the octet code of the original character (%HEX-CODE). For instance US-ASCII space character would be represented with %20. This is often referred as escaped ending or percent-encoding. Since the server decodes the URL from the requests, it may restrict the access to some URL paths by validating and filtering out the URL requests it received. An attacker will try to craft an URL with a sequence of special characters which once interpreted by the server will be equivalent to a forbidden URL. It can be difficult to protect against this attack since the URL can contain other format of encoding such as UTF-8 encoding, Unicode-encoding, etc.
CAPEC-72 URL Encoding
This attack targets the encoding of the URL. An adversary can take advantage of the multiple way of encoding an URL and abuse the interpretation of the URL.
CAPEC-76 Manipulating Web Input to File System Calls
An attacker manipulates inputs to the target software which the target software passes to file system calls in the OS. The goal is to gain access to, and perhaps modify, areas of the file system that the target software did not intend to be accessible.
CAPEC-78 Using Escaped Slashes in Alternate Encoding
This attack targets the use of the backslash in alternate encoding. An adversary can provide a backslash as a leading character and causes a parser to believe that the next character is special. This is called an escape. By using that trick, the adversary tries to exploit alternate ways to encode the same character which leads to filter problems and opens avenues to attack.
CAPEC-79 Using Slashes in Alternate Encoding
This attack targets the encoding of the Slash characters. An adversary would try to exploit common filtering problems related to the use of the slashes characters to gain access to resources on the target host. Directory-driven systems, such as file systems and databases, typically use the slash character to indicate traversal between directories or other container components. For murky historical reasons, PCs (and, as a result, Microsoft OSs) choose to use a backslash, whereas the UNIX world typically makes use of the forward slash. The schizophrenic result is that many MS-based systems are required to understand both forms of the slash. This gives the adversary many opportunities to discover and abuse a number of common filtering problems. The goal of this pattern is to discover server software that only applies filters to one version, but not the other.
CAPEC-80 Using UTF-8 Encoding to Bypass Validation Logic
This attack is a specific variation on leveraging alternate encodings to bypass validation logic. This attack leverages the possibility to encode potentially harmful input in UTF-8 and submit it to applications not expecting or effective at validating this encoding standard making input filtering difficult. UTF-8 (8-bit UCS/Unicode Transformation Format) is a variable-length character encoding for Unicode. Legal UTF-8 characters are one to four bytes long. However, early version of the UTF-8 specification got some entries wrong (in some cases it permitted overlong characters). UTF-8 encoders are supposed to use the "shortest possible" encoding, but naive decoders may accept encodings that are longer than necessary. According to the RFC 3629, a particularly subtle form of this attack can be carried out against a parser which performs security-critical validity checks against the UTF-8 encoded form of its input, but interprets certain illegal octet sequences as characters.

Note

CWE-114 is a Class, but it is listed a child of CWE-73 in view 1000. This suggests some abstraction problems that should be resolved in future versions.

Riferimenti

REF-6

Seven Pernicious Kingdoms: A Taxonomy of Software Security Errors
Katrina Tsipenyuk, Brian Chess, Gary McGraw.
https://samate.nist.gov/SSATTM_Content/papers/Seven%20Pernicious%20Kingdoms%20-%20Taxonomy%20of%20Sw%20Security%20Errors%20-%20Tsipenyuk%20-%20Chess%20-%20McGraw.pdf

REF-45

OWASP Enterprise Security API (ESAPI) Project
OWASP.
https://owasp.org/www-project-enterprise-security-api/

Invio

Nome Organizzazione Data Data di rilascio Version
7 Pernicious Kingdoms 2006-07-19 +00:00 2006-07-19 +00:00 Draft 3

Modifiche

Nome Organizzazione Data Commento
Eric Dalci Cigital 2008-07-01 +00:00 updated Time_of_Introduction
CWE Content Team MITRE 2008-09-08 +00:00 updated Relationships, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities
CWE Content Team MITRE 2009-01-12 +00:00 updated Applicable_Platforms, Causal_Nature, Common_Consequences, Demonstrative_Examples, Description, Observed_Examples, Other_Notes, Potential_Mitigations, References, Relationship_Notes, Relationships, Weakness_Ordinalities
CWE Content Team MITRE 2009-03-10 +00:00 updated Potential_Mitigations, Relationships
CWE Content Team MITRE 2009-07-27 +00:00 updated Demonstrative_Examples
CWE Content Team MITRE 2009-10-29 +00:00 updated Common_Consequences, Description
CWE Content Team MITRE 2009-12-28 +00:00 updated Detection_Factors
CWE Content Team MITRE 2010-02-16 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2011-06-01 +00:00 updated Common_Consequences, Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2011-09-13 +00:00 updated Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2012-05-11 +00:00 updated Demonstrative_Examples, References, Related_Attack_Patterns, Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2012-10-30 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2014-07-30 +00:00 updated Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2017-11-08 +00:00 updated Applicable_Platforms, Likelihood_of_Exploit, Modes_of_Introduction, Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2020-02-24 +00:00 updated Potential_Mitigations, References, Relationships, Time_of_Introduction, Type
CWE Content Team MITRE 2020-06-25 +00:00 updated Potential_Mitigations, Relationships
CWE Content Team MITRE 2021-03-15 +00:00 updated Maintenance_Notes, Potential_Mitigations
CWE Content Team MITRE 2021-10-28 +00:00 updated Relationships
CWE Content Team MITRE 2023-01-31 +00:00 updated Description, Detection_Factors, Potential_Mitigations
CWE Content Team MITRE 2023-04-27 +00:00 updated Potential_Mitigations, Relationships
CWE Content Team MITRE 2023-06-29 +00:00 updated Mapping_Notes
CWE Content Team MITRE 2023-10-26 +00:00 updated Observed_Examples
CWE Content Team MITRE 2025-09-09 +00:00 updated References
CWE Content Team MITRE 2025-12-11 +00:00 updated Relationships
Le informazioni presentate su CVE Find provengono da diverse fonti di riferimento attentamente selezionate. I dati CVE sono forniti da MITRE Corporation e dal National Vulnerability Database (NVD). Il catalogo delle vulnerabilità sfruttate conosciute (KEV) proviene dalla Cybersecurity and Infrastructure Security Agency (CISA), mentre i punteggi EPSS provengono da FIRST.org. Inoltre, i dati relativi alle vulnerabilità software (CWE) e ai pattern di attacco comuni (CAPEC) sono mantenuti da MITRE Corporation, e le informazioni sulle configurazioni hardware e software (CPE) sono fornite da NVD.