CVE-2024-4577

In PHP versions 8.1.* before 8.1.29, 8.2.* before 8.2.20, 8.3.* before 8.3.8, when using Apache and PHP-CGI on Windows, if the system is set up to use certain code pages, Windows may use “Best-Fit” behavior to replace characters in command line given to Win32 API functions. PHP CGI module may misinterpret those characters as PHP options, which may allow a malicious user to pass options to PHP binary being run, and thus reveal the source code of scripts, run arbitrary PHP code on the server, etc.

Recent assessments:

sfewer-r7 at June 10, 2024 5:00pm UTC reported:

I have rated the attacker value as high, as if the requirement to exploitation are met the attacker can get remote unauthenticated RCE on the target Windows server. I have rated the Exploitability as Low as there are several prerequisites for a target to be vulnerable, specifically.

• Target must be a web server running on a Windows system. A Web server on Linux for example can not be vulnerable. Currently I have only seen vulnerable Apache based configurations. I could not get IIS to be vulnerable during testing.

• Target webserver must expose PHP in CGI mode (as opposed to FastCGI mode which is generally more common), or expose the CGI binary directly through an Apache ScriptAlias directive.

• The target Windows OS must have its system locale set to either Japanese (Code page 932) or Chinese (Code pages 950 or 936). For this reason most systems that meet the other requirements will not be exploitable, as the systems locale must use a code page that can cause the vulnerability.

It is worth noting that XAMPP for Windows is in a vulnerable configuration by default, however the target Windows system XAMPP is running on still must meet the locale requirement of either Japanese or Chinese as mentioned above.

Assessed Attacker Value: 4
Assessed Attacker Value: 4Assessed Attacker Value: 2