Sicherheitslücke in Version 4.3.0

[Sven Rautenberg]

Moin!

Wie gestern abend auf der PHP-Announce-Mailingliste verbreitet wurde, hat PHP 4.3.0 eine Sicherheitslücke, wenn es als CGI betrieben wird.

Der Bug verhindert, dass die Option "--enable-force-cgi-redirect" bzw. die PHP.INI-Option "cgi.force_redirect" wirksam werden. Dadurch ist der Zugriff auf alle Dateien möglich, die der Webserver-User lesen kann - und wenn der Angreifer es schafft, in solch eine Datei Code einzufügen, kann dieser auch ausgeführt werden. Beispielsweise in das Access-Logfile.

Das Update auf PHP Version 4.3.1 steht zum Download zur Verfügung.

- Sven Rautenberg

Die Original-Nachricht:
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PHP Security Advisory: CGI vulnerability in PHP version 4.3.0

Issued on: February 17, 2003
Software:  PHP/CGI version 4.3.0
Platforms: All

The PHP Group has learned of a serious security vulnerability in
   the CGI SAPI of PHP version 4.3.0.

Description

PHP contains code for preventing direct access to the CGI binary with
   configure option "--enable-force-cgi-redirect" and php.ini option
   "cgi.force_redirect". In PHP 4.3.0 there is a bug which renders these
   options useless.

NOTE: This bug does NOT affect any of the other SAPI modules.
         (such as the Apache or ISAPI modules, etc.)

Impact

Anyone with access to websites hosted on a web server which employs
   the CGI module may exploit this vulnerability to gain access to any file
   readable by the user under which the webserver runs.

A remote attacker could also trick PHP into executing arbitrary PHP code
   if attacker is able to inject the code into files accessible by the CGI.
   This could be for example the web server access-logs.

Solution

The PHP Group has released a new PHP version, 4.3.1, which incorporates
   a fix for the vulnerability. All users of affected PHP versions are
   encouraged to upgrade to this latest version. The downloads web site at

http://www.php.net/downloads.php

has the new 4.3.1 source tarballs, Windows binaries and source patch
   from 4.3.0 available for download. You will only need to upgrade if
   you're using the CGI module of PHP 4.3.0. There are no other bugfixes
   contained in this release.

Workaround

None.

Credits

The PHP Group would like to thank Kosmas Skiadopoulos for discovering
   this vulnerability.

Copyright (c) 2003 The PHP Group.

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