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e-matters GmbH
http://www.e-matters.de
-= Security Advisory =-
Advisory: Multiple Remote Vulnerabilites within PHP's fileupload code
Release Date: 2002/02/27
Last Modified: 2002/02/28
Author: Stefan Esser [s.esser@e-matters.de]
Application: PHP v3.0.10-v3.0.18, v4.0.1-v4.1.1
Severity: Several vulnerabilities in PHP's fileupload code allow
remote compromise
Risk: Critical
Vendor Status: Patches Released
Reference: http://security.e-matters.de/advisories/012002.html
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 3.0.10-3.0.18
- 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 the boundary check vulnerabilities
are
only exploitable on linux or solaris.
The heap off by one is only exploitable on linux(maybe solaris)x86
and the arbitrary heap overflow in PHP3 is exploitable on most OS
and architectures. (This includes *BSD, Windows, Linux, Solaris)
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.
Please notice, that you are not only vulnerable if you run scripts
that use uploaded files. You are vulnerable if you run any script!
If you have PHP only installed but there is no script on your
server you are not vulnerable.
Please notice also, that the PHP team now learned that there is
really a badly working exploit circulating in the underground.
At the time this advisory was originaly posted we only heard
rumours.
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:
http://www.php.net/downloads.php
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:
http://security.e-matters.de/gpg_key.asc
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.
===========================================================
-----BEGIN PGP SIGNED MESSAGE-----
CERT Advisory CA-2002-05 Multiple Vulnerabilities in PHP fileupload
Original release date: February 27, 2002
Last revised: --
Source: CERT/CC
A complete revision history can be found at the end of this file.
Systems Affected
* Web servers running PHP
Overview
Multiple vulnerabilities exist in the PHP scripting language. These
vulnerabilities could allow a remote attacker to execute arbitrary
code with the privileges of the PHP process.
I. Description
PHP is a scripting language widely used in web development. PHP can be
installed on a variety of web servers, including Apache, IIS, Caudium,
Netscape and iPlanet, OmniHTTPd and others. Vulnerabilities in the
php_mime_split function may allow an intruder to execute arbitrary
code with the privileges of the web server. For additional details,
see
http://security.e-matters.de/advisories/012002.html
Web servers that do not have PHP installed are not affected by this
vulnerability.
The CERT/CC is tracking this set of vulnerabilities as VU#297363. At
this time, these vulnerabilities have not been assigned a CVE
identifier.
II. Impact
Intruders can execute arbitrary code with the privileges of the web
server, or interrupt normal operations of the web server.
III. Solution
Apply a Patch
Upgrade to PHP version 4.1.2, available from
http://www.php.net/do_download.php?d...p-4.1.2.tar.gz
If upgrading is not possible, apply patches as described at
http://www.php.net/downloads.php:
* For PHP 4.10/4.11
http://www.php.net/do_download.php?d....diff-4.1.x.gz
* For PHP 4.06
http://www.php.net/do_download.php?d....diff-4.0.6.gz
* For PHP 3.0
http://www.php.net/do_download.php?d....c.diff-3.0.gz
If you are using version 4.20-dev, you are not affected by this
vulnerability. Quoting from
http://security.e-matters.de/advisories/012002.htm:
"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."
Disable fileuploads
If upgrading is not possible or a patch cannot be applied, you can
avoid these vulnerabilities by disabling fileupload support. Edit the
PHP configuration file php.ini as follows:
file_uploads = off
Note that this setting only applies to version 4.0.3 and above.
However, this will prevent you from using fileuploads, which may not
be acceptable in your environment.
Appendix A. - Vendor Information
This appendix contains information provided by vendors for this
advisory. When vendors report new information to the CERT/CC, we
update this section and note the changes in our revision history. If a
particular vendor is not listed below, we have not received their
comments.
Apache Software Foundation
Information about this vulnerability is available from
http://www.php.net
FreeBSD
FreeBSD does not include any version of PHP by default, and so is not
vulnerable. However, the FreeBSD Ports Collection does contain both
PHP3 and PHP4 packages. Updates to the PHP packages are in progress
and corrected packages will be available in the near future.
MandrakeSoft
MandrakeSoft distributes PHP in all distributions and we are currently
working on patching our versions of PHP for Linux-Mandrake 7.1 and
7.2; Mandrake Linux 8.0, 8.0/ppc, 8.1, and 8.1/ia64; Single Network
Firewall 7.2; Corporate Server 1.0.1.
We anticipate having the updates out by the end of the week.
Microsoft
We do not use PHP in any products.
NCSA
NCSA does not include PHP as an add-in or bundled component in any
products distributed.
Red Hat
Red Hat was notified of this issue on 27th February 2002. All
supported versions of Red Hat Linux ship with PHP packages that are
affected by these vulnerabilities. We will shortly be releasing errata
packages which contain patched versions that are not vulnerable. The
errata packages and our advisory will be available on our web site at
the URL below. At the same time users of the Red Hat Network will be
able to update their systems to patched versions using the up2date
tool.
http://www.redhat.com/support/errata/RHSA-2002-035.html
_________________________________________________________________
The CERT Coordination Center thanks Stefan Esser, upon whose advisory
this document is largely based.
_________________________________________________________________
Author: Shawn V. Hernan
_________________________________________________________________
Appendix B. - References
1. http://www.kb.cert.org/vuls/id/297363
2. http://security.e-matters.de/advisories/012002.html
3. http://www.iss.net/security_center/static/8281.php
______________________________________________________________________
This document is available from:
http://www.cert.org/advisories/CA-2002-05.html
______________________________________________________________________
CERT/CC Contact Information
Email: cert@cert.org
Phone: +1 412-268-7090 (24-hour hotline)
Fax: +1 412-268-6989
Postal address:
CERT Coordination Center
Software Engineering Institute
Carnegie Mellon University
Pittsburgh PA 15213-3890
U.S.A.
CERT/CC personnel answer the hotline 08:00-17:00 EST(GMT-5) /
EDT(GMT-4) Monday through Friday; they are on call for emergencies
during other hours, on U.S. holidays, and on weekends.
Using encryption
We strongly urge you to encrypt sensitive information sent by email.
Our public PGP key is available from
http://www.cert.org/CERT_PGP.key
If you prefer to use DES, please call the CERT hotline for more
information.
Getting security information
CERT publications and other security information are available from
our web site
http://www.cert.org/
To subscribe to the CERT mailing list for advisories and bulletins,
send email to majordomo@cert.org. Please include in the body of your
message
subscribe cert-advisory
* "CERT" and "CERT Coordination Center" are registered in the U.S.
Patent and Trademark Office.
______________________________________________________________________
NO WARRANTY
Any material furnished by Carnegie Mellon University and the Software
Engineering Institute is furnished on an "as is" basis. Carnegie
Mellon University makes no warranties of any kind, either expressed or
implied as to any matter including, but not limited to, warranty of
fitness for a particular purpose or merchantability, exclusivity or
results obtained from use of the material. Carnegie Mellon University
does not make any warranty of any kind with respect to freedom from
patent, trademark, or copyright infringement.
_________________________________________________________________
Conditions for use, disclaimers, and sponsorship information
Copyright 2002 Carnegie Mellon University.
Revision History
February 27, 2002: Initial release
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[Editiert von hand am 28-02-2002 um 20:04]
http://www.e-matters.de
-= Security Advisory =-
Advisory: Multiple Remote Vulnerabilites within PHP's fileupload code
Release Date: 2002/02/27
Last Modified: 2002/02/28
Author: Stefan Esser [s.esser@e-matters.de]
Application: PHP v3.0.10-v3.0.18, v4.0.1-v4.1.1
Severity: Several vulnerabilities in PHP's fileupload code allow
remote compromise
Risk: Critical
Vendor Status: Patches Released
Reference: http://security.e-matters.de/advisories/012002.html
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 3.0.10-3.0.18
- 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 the boundary check vulnerabilities
are
only exploitable on linux or solaris.
The heap off by one is only exploitable on linux(maybe solaris)x86
and the arbitrary heap overflow in PHP3 is exploitable on most OS
and architectures. (This includes *BSD, Windows, Linux, Solaris)
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.
Please notice, that you are not only vulnerable if you run scripts
that use uploaded files. You are vulnerable if you run any script!
If you have PHP only installed but there is no script on your
server you are not vulnerable.
Please notice also, that the PHP team now learned that there is
really a badly working exploit circulating in the underground.
At the time this advisory was originaly posted we only heard
rumours.
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:
http://www.php.net/downloads.php
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:
http://security.e-matters.de/gpg_key.asc
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.
===========================================================
-----BEGIN PGP SIGNED MESSAGE-----
CERT Advisory CA-2002-05 Multiple Vulnerabilities in PHP fileupload
Original release date: February 27, 2002
Last revised: --
Source: CERT/CC
A complete revision history can be found at the end of this file.
Systems Affected
* Web servers running PHP
Overview
Multiple vulnerabilities exist in the PHP scripting language. These
vulnerabilities could allow a remote attacker to execute arbitrary
code with the privileges of the PHP process.
I. Description
PHP is a scripting language widely used in web development. PHP can be
installed on a variety of web servers, including Apache, IIS, Caudium,
Netscape and iPlanet, OmniHTTPd and others. Vulnerabilities in the
php_mime_split function may allow an intruder to execute arbitrary
code with the privileges of the web server. For additional details,
see
http://security.e-matters.de/advisories/012002.html
Web servers that do not have PHP installed are not affected by this
vulnerability.
The CERT/CC is tracking this set of vulnerabilities as VU#297363. At
this time, these vulnerabilities have not been assigned a CVE
identifier.
II. Impact
Intruders can execute arbitrary code with the privileges of the web
server, or interrupt normal operations of the web server.
III. Solution
Apply a Patch
Upgrade to PHP version 4.1.2, available from
http://www.php.net/do_download.php?d...p-4.1.2.tar.gz
If upgrading is not possible, apply patches as described at
http://www.php.net/downloads.php:
* For PHP 4.10/4.11
http://www.php.net/do_download.php?d....diff-4.1.x.gz
* For PHP 4.06
http://www.php.net/do_download.php?d....diff-4.0.6.gz
* For PHP 3.0
http://www.php.net/do_download.php?d....c.diff-3.0.gz
If you are using version 4.20-dev, you are not affected by this
vulnerability. Quoting from
http://security.e-matters.de/advisories/012002.htm:
"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."
Disable fileuploads
If upgrading is not possible or a patch cannot be applied, you can
avoid these vulnerabilities by disabling fileupload support. Edit the
PHP configuration file php.ini as follows:
file_uploads = off
Note that this setting only applies to version 4.0.3 and above.
However, this will prevent you from using fileuploads, which may not
be acceptable in your environment.
Appendix A. - Vendor Information
This appendix contains information provided by vendors for this
advisory. When vendors report new information to the CERT/CC, we
update this section and note the changes in our revision history. If a
particular vendor is not listed below, we have not received their
comments.
Apache Software Foundation
Information about this vulnerability is available from
http://www.php.net
FreeBSD
FreeBSD does not include any version of PHP by default, and so is not
vulnerable. However, the FreeBSD Ports Collection does contain both
PHP3 and PHP4 packages. Updates to the PHP packages are in progress
and corrected packages will be available in the near future.
MandrakeSoft
MandrakeSoft distributes PHP in all distributions and we are currently
working on patching our versions of PHP for Linux-Mandrake 7.1 and
7.2; Mandrake Linux 8.0, 8.0/ppc, 8.1, and 8.1/ia64; Single Network
Firewall 7.2; Corporate Server 1.0.1.
We anticipate having the updates out by the end of the week.
Microsoft
We do not use PHP in any products.
NCSA
NCSA does not include PHP as an add-in or bundled component in any
products distributed.
Red Hat
Red Hat was notified of this issue on 27th February 2002. All
supported versions of Red Hat Linux ship with PHP packages that are
affected by these vulnerabilities. We will shortly be releasing errata
packages which contain patched versions that are not vulnerable. The
errata packages and our advisory will be available on our web site at
the URL below. At the same time users of the Red Hat Network will be
able to update their systems to patched versions using the up2date
tool.
http://www.redhat.com/support/errata/RHSA-2002-035.html
_________________________________________________________________
The CERT Coordination Center thanks Stefan Esser, upon whose advisory
this document is largely based.
_________________________________________________________________
Author: Shawn V. Hernan
_________________________________________________________________
Appendix B. - References
1. http://www.kb.cert.org/vuls/id/297363
2. http://security.e-matters.de/advisories/012002.html
3. http://www.iss.net/security_center/static/8281.php
______________________________________________________________________
This document is available from:
http://www.cert.org/advisories/CA-2002-05.html
______________________________________________________________________
CERT/CC Contact Information
Email: cert@cert.org
Phone: +1 412-268-7090 (24-hour hotline)
Fax: +1 412-268-6989
Postal address:
CERT Coordination Center
Software Engineering Institute
Carnegie Mellon University
Pittsburgh PA 15213-3890
U.S.A.
CERT/CC personnel answer the hotline 08:00-17:00 EST(GMT-5) /
EDT(GMT-4) Monday through Friday; they are on call for emergencies
during other hours, on U.S. holidays, and on weekends.
Using encryption
We strongly urge you to encrypt sensitive information sent by email.
Our public PGP key is available from
http://www.cert.org/CERT_PGP.key
If you prefer to use DES, please call the CERT hotline for more
information.
Getting security information
CERT publications and other security information are available from
our web site
http://www.cert.org/
To subscribe to the CERT mailing list for advisories and bulletins,
send email to majordomo@cert.org. Please include in the body of your
message
subscribe cert-advisory
* "CERT" and "CERT Coordination Center" are registered in the U.S.
Patent and Trademark Office.
______________________________________________________________________
NO WARRANTY
Any material furnished by Carnegie Mellon University and the Software
Engineering Institute is furnished on an "as is" basis. Carnegie
Mellon University makes no warranties of any kind, either expressed or
implied as to any matter including, but not limited to, warranty of
fitness for a particular purpose or merchantability, exclusivity or
results obtained from use of the material. Carnegie Mellon University
does not make any warranty of any kind with respect to freedom from
patent, trademark, or copyright infringement.
_________________________________________________________________
Conditions for use, disclaimers, and sponsorship information
Copyright 2002 Carnegie Mellon University.
Revision History
February 27, 2002: Initial release
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[Editiert von hand am 28-02-2002 um 20:04]
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