SB2021092901 - Path traversal in PHP

Description

This security bulletin contains information about 1 security vulnerability.

1) Absolute Path Traversal (CVE-ID: CVE-2021-21706)

The vulnerability allows a remote attacker overwrite files on the system.

The vulnerability exists due to insufficient filtration of file names in the php_zip_make_relative_path() function on Windows systems. A remote attacker can construct a specially crafted ZIP archive, which once extracted by the ZipArchive::extractTo() function, can overwrite files outside of the destination directory.

Successful exploitation of the vulnerability may allow an attacker to overwrite arbitrary files on the system with privileges of the web server, but requires that the web application is running on Windows.

Remediation

Install update from vendor's website.

References

• https://www.php.net/ChangeLog-7.php#7.4.24
• https://bugs.php.net/bug.php?id=81420
• https://www.php.net/ChangeLog-7.php#7.3.31