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Windows Hard Link

Incomplete Variant
Structure: Simple
Description

The product, when opening a file or directory, does not sufficiently handle when the name is associated with a hard link to a target that is outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.

Extended Description

Failure for a system to check for hard links can result in vulnerability to different types of attacks. For example, an attacker can escalate their privileges if a file used by a privileged program is replaced with a hard link to a sensitive file (e.g. AUTOEXEC.BAT). When the process opens the file, the attacker can assume the privileges of that process, or prevent the program from accurately processing data.
Common Consequences 1
Scope: ConfidentialityIntegrity

Impact: Read Files or DirectoriesModify Files or Directories
Potential Mitigations 1
Phase: Architecture and Design

Strategy: Separation of Privilege

Follow the principle of least privilege when assigning access rights to entities in a software system. Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.
Observed Examples 2
CVE-2002-0725File system allows local attackers to hide file usage activities via a hard link to the target file, which causes the link to be recorded in the audit trail instead of the target file.
CVE-2003-0844Web server plugin allows local users to overwrite arbitrary files via a symlink attack on predictable temporary filenames.
References 1
The Art of Software Security Assessment
Mark Dowd, John McDonald, and Justin Schuh
Addison Wesley
2006
ID: REF-62
Applicable Platforms
Languages:
Not Language-Specific : Undetermined
Modes of Introduction
Implementation
Operation
Functional Areas
  1. File Processing
Affected Resources
  1. File or Directory
Related Weaknesses
ChildOf: Improper Link Resolution Before File Access ('Link Following') (CWE-59)
Taxonomy Mapping
  • PLOVER
  • CERT C Secure Coding
  • Software Fault Patterns