Multiple critical remote vulnerabilities exist in several versions of PHP. We found several flaws in the way PHP handles multipart/form-data POST requests. Each of the flaws could allow an attacker to execute arbitrary code on the victim's system.. . .
Multiple critical remote vulnerabilities exist in several versions of PHP. We found several flaws in the way PHP handles multipart/form-data POST requests. Each of the flaws could allow an attacker to execute arbitrary code on the victim's system.

                            e-matters GmbH                           www.e-matters.de                        -= Security  Advisory =-         Advisory: Multiple Remote Vulnerabilites within PHP's fileupload code  Release Date: 2002/02/27 Last Modified: 2002/02/27        Author: Stefan Esser [s.esser@e-matters.de]    Application: PHP v3.10-v3.18, v4.0.1-v4.1.1      Severity: Several vulnerabilities in PHP's fileupload code allow                remote compromise          Risk: Critical Vendor Status: Patches Released     Reference:     Overview:             We found several flaws in the way PHP handles multipart/form-data POST     requests. Each of the flaws could allow an attacker to execute arbitrary     code on the victim's  system.            Details:     PHP supports multipart/form-data POST requests (as described in RFC1867)     known as POST fileuploads. Unfourtunately there are several flaws in the    php_mime_split function that could be used by an attacker to execute    arbitrary code. During our research we found out that not only PHP4 but    also older versions from the PHP3 tree are vulnerable.            The following is a list of bugs we found:        PHP 3.10-3.18           - broken boundary check    (hard to exploit)       - arbitrary heap overflow  (easy exploitable)        PHP 4.0.1-4.0.3pl1           - broken boundary check    (hard to exploit)       - heap off by one          (easy exploitable)           PHP 4.0.2-4.0.5           - 2 broken boundary checks (one very easy and one hard to exploit)           PHP 4.0.6-4.0.7RC2           - broken boundary check    (very easy to exploit)           PHP 4.0.7RC3-4.1.1           - broken boundary check    (hard to exploit)      Finally I want to mention that most of these vulnerabilities are     exploitable only on linux or solaris. But the heap off by one is only    exploitable on x86 architecture and the arbitrary heap overflow in    PHP3 is exploitable on most OS and architectures. (This includes *BSD)     Users running PHP 4.2.0-dev from cvs are not vulnerable to any of the    described bugs because the fileupload code was completly rewritten for     the 4.2.0 branch.       Proof of Concept:     e-matters is not going to release exploits for any of the discovered    vulnerabilities to the public.       Vendor Response:     Because I am part of the php developer team there is not much I can    write here...     27th February 2002 - An updated version of php and the patch for                         these vulnerabilities are now available at:                         PHP: Downloads                   Recommendation:     If you are running PHP 4.0.3 or above one way to workaround these     bugs is to disable the fileupload support within your php.ini     (file_uploads = Off) If you are running php as module keep in mind    to restart the webserver. Anyway you should better install the     fixed or a properly patched version to be safe.         Sidenotice:      This advisory is so short because I don't want to give out more info    than is needed.        Users running the developer version of php (4.2.0-dev) are not     vulnerable to these bugs because the fileupload support was completly    rewritten for that branch.   GPG-Key:               pub  1024D/75E7AAD6 2002-02-26 e-matters GmbH - Securityteam    Key fingerprint = 43DD 843C FAB9 832A E5AB  CAEB 81F2 8110 75E7 AAD6   Copyright 2002 Stefan Esser. All rights reserved.