PHP: Arbitrary code execution

Background

PHP is an open source general-purpose scripting language that is especially suited for web development.

Description

A underflow in env_path_info in PHP-FPM under certain configurations can be exploited to gain remote code execution.

Impact

A remote attacker, by sending special crafted HTTP requests, could possibly execute arbitrary code with the privileges of the process, or cause a Denial of Service condition.

Workaround

If patching is not feasible, the suggested workaround is to include checks to verify whether or not a file exists before passing to PHP.

Resolution

All PHP 5.6 users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=dev-lang/php-5.6.40-r7"

All PHP 7.1 users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=dev-lang/php-7.1.33"

All PHP 7.2 users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=dev-lang/php-7.2.24"

All PHP 7.3 users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=dev-lang/php-7.3.11"