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Description
The software, when opening a file or directory, does not sufficiently account for 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 software to operate on unauthorized files.
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. /etc/passwd). When the process opens the file, the attacker can assume the privileges of that process.
Modes of Introduction:
– Implementation
Related Weaknesses
CWE-59
Consequences
Confidentiality, Integrity: Read Files or Directories, Modify Files or Directories
Potential Mitigations
Phase: Architecture and Design
Description:
CVE References
- CVE-2001-1494
- Hard link attack, file overwrite; interesting because program checks against soft links
- CVE-2002-0793
- Hard link and possibly symbolic link following vulnerabilities in embedded operating system allow local users to overwrite arbitrary files.
- CVE-2003-0578
- Server creates hard links and unlinks files as root, which allows local users to gain privileges by deleting and overwriting arbitrary files.
- CVE-1999-0783
- Operating system allows local users to conduct a denial of service by creating a hard link from a device special file to a file on an NFS file system.
- CVE-2004-1603
- Web hosting manager follows hard links, which allows local users to read or modify arbitrary files.
- CVE-2004-1901
- Package listing system allows local users to overwrite arbitrary files via a hard link attack on the lockfiles.
- CVE-2005-0342
- The Finder in Mac OS X and earlier allows local users to overwrite arbitrary files and gain privileges by creating a hard link from the .DS_Store file to an arbitrary file.
