Base weakness

Draft

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

Also known as: insecure temporary file, Zip Slip

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

547

Recorded CVEs

With this primary weakness

KEVs

In the CISA KEV catalog

Medium

Likelihood of exploit

Per MITRE

Base

Abstraction

MITRE classification

Overview

CWE-59 (Improper Link Resolution Before File Access ('Link Following')) is a base-level software weakness catalogued by MITRE in the Common Weakness Enumeration (CWE). It describes a recurring type of mistake that can lead to exploitable security vulnerabilities.

Illustrative examples

Real CVEs that MITRE cites as examples of this weakness.

CVE-1999-1386 — Some versions of Perl follow symbolic links when running with the -e option, which allows local users to overwrite arbitrary files via a symlink attack.
CVE-2000-1178 — Text editor follows symbolic links when creating a rescue copy during an abnormal exit, which allows local users to overwrite the files of other users.
CVE-2004-0217 — Antivirus update allows local users to create or append to arbitrary files via a symlink attack on a logfile.
CVE-2003-0517 — Symlink attack allows local users to overwrite files.
CVE-2004-0689 — Window manager does not properly handle when certain symbolic links point to "stale" locations, which could allow local users to create or truncate arbitrary files.
CVE-2005-1879 — Second-order symlink vulnerabilities
CVE-2005-1880 — Second-order symlink vulnerabilities
CVE-2005-1916 — Symlink in Python program
CVE-2000-0972 — Setuid product allows file reading by replacing a file being edited with a symlink to the targeted file, leaking the result in error messages when parsing fails.
CVE-2005-0824 — Signal causes a dump that follows symlinks.
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-2005-1111 — Hard link race condition
CVE-2000-0342 — Mail client allows remote attackers to bypass the user warning for executable attachments such as .exe, .com, and .bat by using a .lnk file that refers to the attachment, aka "Stealth Attachment."
CVE-2001-1042 — FTP server allows remote attackers to read arbitrary files and directories by uploading a .lnk (link) file that points to the target file.
CVE-2001-1043 — FTP server allows remote attackers to read arbitrary files and directories by uploading a .lnk (link) file that points to the target file.
CVE-2005-0587 — Browser allows remote malicious web sites to overwrite arbitrary files by tricking the user into downloading a .LNK (link) file twice, which overwrites the file that was referenced in the first .LNK file.
CVE-2001-1386 — ".LNK." - .LNK with trailing dot
CVE-2003-1233 — Rootkits can bypass file access restrictions to Windows kernel directories using NtCreateSymbolicLinkObject function to create symbolic link
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.
CVE-2015-3629 — A Libcontainer used in Docker Engine allows local users to escape containerization and write to an arbitrary file on the host system via a symlink attack in an image when respawning a container.
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-2020-27833 — "Zip Slip" vulnerability in container management product allows writing arbitrary files outside intended directory via a container image (.tar format) with filenames that are symbolic links that point to other files within the same tar file; however, the files being pointed to can also be symbolic links to destinations outside the intended directory, bypassing the initial check.

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

Overview

Background

Real-world CVEs

Common consequences

How it happens

When it is introduced

Applies to

How to prevent it

How to detect it

Automated Static Analysis - Binary or Bytecode

Manual Static Analysis - Binary or Bytecode

Dynamic Analysis with Automated Results Interpretation

Dynamic Analysis with Manual Results Interpretation

Manual Static Analysis - Source Code

Automated Static Analysis - Source Code

Architecture or Design Review

Illustrative examples

Terminology & mappings

Alternate terms

Mapped taxonomies

Attack patterns

Frequently asked questions

What is CWE-59?

What CVEs are caused by CWE-59?

How do you prevent CWE-59?

How is CWE-59 detected?

What are the consequences of CWE-59?

Is CWE-59 actively exploited?

References

Stay ahead of CWE-59

Overview

Background

Real-world CVEs

Common consequences

How it happens

When it is introduced

Applies to

How to prevent it

How to detect it

Automated Static Analysis - Binary or Bytecode

Manual Static Analysis - Binary or Bytecode

Dynamic Analysis with Automated Results Interpretation

Dynamic Analysis with Manual Results Interpretation

Manual Static Analysis - Source Code

Automated Static Analysis - Source Code

Architecture or Design Review

Illustrative examples

Related weaknesses

Parent

Child

Related

Terminology & mappings

Alternate terms

Mapped taxonomies

Attack patterns

Frequently asked questions

What is CWE-59?

What CVEs are caused by CWE-59?

How do you prevent CWE-59?

How is CWE-59 detected?

What are the consequences of CWE-59?

Is CWE-59 actively exploited?

References

Stay ahead of CWE-59