Windows Hard Link

Opis

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.

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.

Skutki

• Confidentiality, Integrity

  Read Files or Directories; Modify Files or Directories

Zapobieganie

• Architecture and Design · 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.

Przykłady podatności

• CVE-2002-0725 File 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-2003-0844 Web server plugin allows local users to overwrite arbitrary files via a symlink attack on predictable temporary filenames.

Słabość nadrzędna

• CWE-59 Improper Link Resolution Before File Access ('Link Following')

Kiedy powstaje

• Implementation
• Operation

Dotyczy

Not Language-Specific, Windows, Not Technology-Specific

Źródła

1. The Art of Software Security Assessment — Mark Dowd, John McDonald, Justin Schuh, Chapter 11, "Links", Page 676, Addison Wesley, 2006