CVE-2011-4116

_is_safe in the File::Temp module for Perl does not properly handle symlinks.

Weakness

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.

Affected Software

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.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/132.html
• https://cwe.mitre.org/data/definitions/17.html
• https://cwe.mitre.org/data/definitions/35.html
• https://cwe.mitre.org/data/definitions/76.html

References

• http://www.openwall.com/lists/oss-security/2011/11/04/2
• http://www.openwall.com/lists/oss-security/2011/11/04/4
• https://github.com/Perl-Toolchain-Gang/File-Temp/issues/14
• https://rt.cpan.org/Public/Bug/Display.html?id=69106
• https://seclists.org/oss-sec/2011/q4/238