CWE-62
UNIX Hard Link
Description
The product, 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 product 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.
Parent Weaknesses (ChildOf)
Common Consequences
Scope
Impact
Read Files or Directories, Modify Files or Directories
Potential Mitigations
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.
CVE-2001-1494Hard link attack, file overwrite; interesting because program checks against soft links
CVE-2002-0793Hard link and possibly symbolic link following vulnerabilities in embedded operating system allow local users to overwrite arbitrary files.
CVE-2003-0578Server creates hard links and unlinks files as root, which allows local users to gain privileges by deleting and overwriting arbitrary files.
CVE-1999-0783Operating 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-2004-1603Web hosting manager follows hard links, which allows local users to read or modify arbitrary files.
CVE-2004-1901Package listing system allows local users to overwrite arbitrary files via a hard link attack on the lockfiles.
CVE-2005-0342The 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.
CVE-2005-1111Hard link race condition
CVE-2021-21272"Zip Slip" vulnerability in Go-based Open Container Initiative (OCI) registries product allows writing arbitrary files outside intended directory via symbolic links or hard links in a gzipped tarball.
CVE-2003-1366setuid root tool allows attackers to read secret data by replacing a temp file with a hard link to a sensitive file
Applicable Platforms
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