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CWE-72: Improper Handling of Apple HFS+ Alternate Data Stream Path

Weakness ID: 72
Abstraction: Variant
Structure: Simple
View customized information:
+ Description
The software does not properly handle special paths that may identify the data or resource fork of a file on the HFS+ file system.
+ Extended Description
If the software chooses actions to take based on the file name, then if an attacker provides the data or resource fork, the software may take unexpected actions. Further, if the software intends to restrict access to a file, then an attacker might still be able to bypass intended access restrictions by requesting the data or resource fork for that file.
+ Relationships
Section HelpThis 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" (CWE-1000)
ChildOfBaseBase - 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.66Improper Handling of File Names that Identify Virtual Resources
+ Background Details

The Apple HFS+ file system permits files to have multiple data input streams, accessible through special paths. The Mac OS X operating system provides a way to access the different data input streams through special paths and as an extended attribute:

- Resource fork: file/..namedfork/rsrc, file/rsrc (deprecated),
- Data fork: file/..namedfork/data (only versions prior to Mac OS X v10.5)

Additionally, on filesystems that lack native support for multiple streams, the resource fork and file metadata may be stored in a file with "._" prepended to the name.

Forks can also be accessed through non-portable APIs.

Forks inherit the file system access controls of the file they belong to.

Programs need to control access to these paths, if the processing of a file system object is dependent on the structure of its path.

+ 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.
Architecture and Design
+ 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.


Class: Not Language-Specific (Undetermined Prevalence)

Operating Systems

Class: macOS (Undetermined Prevalence)

+ 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.

Technical Impact: Read Files or Directories; Modify Files or Directories

+ Demonstrative Examples

Example 1

A web server that interprets FILE.cgi as processing instructions could disclose the source code for FILE.cgi by requesting FILE.cgi/..namedfork/data. This might occur because the web server invokes the default handler which may return the contents of the file.

+ Observed Examples
Server allows remote attackers to read files and resource fork content via HTTP requests to certain special file names related to multiple data streams in HFS+.
+ 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.
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.981SFP Secondary Cluster: Path Traversal
+ Notes


This and similar problems exist because the same resource can have multiple identifiers that dictate which behavior can be performed on the resource.

Research Gap

+ References
[REF-578] NetSec. "NetSec Security Advisory: Multiple Vulnerabilities Resulting From Use Of Apple OSX HFS+". BugTraq. 2005-02-16. <>.
+ Content History
+ Submissions
Submission DateSubmitterOrganization
+ Modifications
Modification DateModifierOrganization
2008-07-01Eric DalciCigital
updated Time_of_Introduction
2008-09-08CWE Content TeamMITRE
updated Relationships, Other_Notes, Taxonomy_Mappings
2008-11-05David RemahlApple
clarified description, provided background details, and added demonstrative example
2008-11-24CWE Content TeamMITRE
updated Applicable_Platforms, Background_Details, Demonstrative_Examples, Description, Name, References
2009-05-27CWE Content TeamMITRE
updated Name
2009-10-29CWE Content TeamMITRE
updated Other_Notes, Theoretical_Notes
2011-06-01CWE Content TeamMITRE
updated Common_Consequences
2012-05-11CWE Content TeamMITRE
updated Observed_Examples, Relationships
2014-07-30CWE Content TeamMITRE
updated Relationships
2017-11-08CWE Content TeamMITRE
updated Applicable_Platforms, References, Relationships, Taxonomy_Mappings
2020-02-24CWE Content TeamMITRE
updated Relationships
+ Previous Entry Names
Change DatePrevious Entry Name
2008-11-24Apple HFS+ Alternate Data Stream
2009-05-27Failure to Handle Apple HFS+ Alternate Data Stream Path
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Page Last Updated: October 13, 2022