Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
===========================================================================
AUSCERT External Security Bulletin Redistribution
ESB-2007.0030 -- [Win][UNIX/Linux]
WordPress multiple vulnerabilities
16 January 2007
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: WordPress 2.0.5 and prior
Publisher: Hardened-PHP Project
Operating System: UNIX variants (UNIX, Linux, OSX)
Windows
Impact: Execute Arbitrary Code/Commands
Cross-site Scripting
Access: Remote/Unauthenticated
Original Bulletin: http://www.hardened-php.net/advisory_012007.140.html
http://www.hardened-php.net/advisory_022007.141.html
Comment: Note that this bulletin contains two advisories regarding WordPress.
Upgrading to WordPress 2.0.6 fixes both issues.
- --------------------------BEGIN INCLUDED TEXT--------------------
- -----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Hardened-PHP Project
www.hardened-php.net
-= Security Advisory =-
Advisory: WordPress Trackback Charset Decoding SQL Injection Vulnerability
Release Date: 2007/01/05
Last Modified: 2007/01/05
Author: Stefan Esser [sesser@hardened-php.net]
Application: WordPress <= 2.0.5
Severity: The support of trackbacks in different charsets can
be used to bypass WordPress's SQL injection protection.
This might result in a compromise of the admin
account and the execution of arbitrary PHP code
on the server
Risk: Critical
Vendor Status: Vendor has released WordPress 2.0.6 which fixes this issue
References: http://www.hardened-php.net/advisory_022007.141.html
Overview:
Quote from http://www.wordpress.org
"WordPress was born out of a desire for an elegant, well-
architectured personal publishing system built on PHP and MySQL
and licensed under the GPL. It is the official successor of
b2/cafelog. WordPress is fresh software, but its roots and
development go back to 2001. It is a mature and stable product.
We hope by focusing on user experience and web standards we can
create a tool different from anything else out there."
While testing WordPress it was discovered that WordPress supports
trackbacks in different charsets when PHP's mbstring extension is
installed. This feature can be abused to bypass WordPress's SQL
parameter escaping which leads to an SQL injection vulnerability
that can result in a compromise of the admin account and end in
a server compromise.
Details:
WordPress supports decoding trackbacks with different charsets
when PHP's mbstring extension is activated. Because the decoding
happens after the database escaping is performed choosing the
right charset for the input data allows bypassing the protection
against SQL injection.
For the demonstration exploit that was shared with the WordPress
developers the UTF-7 charset was chosen, because it is the
easiest to work with. Other multibyte charsets that for example
allow multibyte sequences ending in '\' can also be used.
The exploit first checks if the mbstring extension is loaded by
sending only an UTF-7 encoded '0' in the title field. Because
only a decoded '0' will pass the empty() check this will trigger
two different error situations depending on mbstring availability.
The exploit continues with injecting bogus SQL commands into the
SQL query which will result in WordPress giving out detailed
information about the failed query. This error message is used
to determine the configure database table prefix, which is needed
for the correct exploitation.
In the next step a harmless looking bogus comment is injected
into the comment table with a timestamp in the future. This is
done to stop WordPress from sending notification emails to the
admin during the password hash retrieval.
The rest of the exploit is a simple UNION SELECT injection that
determines password hashes by issuing a request for every bit of
the hash (128 bits) and checking which error message is returned.
With the reconstructed password hash it is possible to create a
WordPress login cookie that can be used to become admin.
As admin it is possible to edit (overwrite) all files within the
blog directory that are writeable. This can be used to inject
arbitrary PHP code in most installations. There exists a protection
that denies loading the wp-config.php file into the file editor,
but it can be tricked by directly sending a POST request that
only saves the files. The wp-config.php file is usually left
writeable after the installation has finished.
Proof of Concept:
The Hardened-PHP Project is not going to release a proof of concept
exploit for this vulnerability.
Disclosure Timeline:
29. December 2006 - Notified security@wordpress.org
05. January 2007 - WordPress 2.0.6 release
05. January 2007 - Public Disclosure
Recommendation:
We strongly recommend to upgrade to WordPress 2.0.6 which also
fixes several other security vulnerabilities not covered by this
advisory.
http://wordpress.org/download/
GPG-Key:
http://www.hardened-php.net/hardened-php-signature-key.asc
pub 1024D/0A864AA1 2004-04-17 Hardened-PHP Signature Key
Key fingerprint = 066F A6D0 E57E 9936 9082 7E52 4439 14CC 0A86 4AA1
Copyright 2007 Stefan Esser. All rights reserved.
- -----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.3 (GNU/Linux)
iD8DBQFFnnfrRDkUzAqGSqERArBQAJ9KW5+1EwwTozgtHQJgZR0XMwLLygCglC4n
5/ova+EUrueU++pt6ohD5q0=
=JqSS
- -----END PGP SIGNATURE-----
- -----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Hardened-PHP Project
www.hardened-php.net
-= Security Advisory =-
Advisory: WordPress CSRF Protection XSS Vulnerability
Release Date: 2007/01/05
Last Modified: 2007/01/05
Author: Stefan Esser [sesser@hardened-php.net]
Application: WordPress <= 2.0.5
Severity: The CSRF protection of WordPress's administration
interface is vulnerable to an XSS vulnerability
which might result in a compromise of the admin
account and the execution of arbitrary PHP code
on the server
Risk: Critical
Vendor Status: Vendor has released WordPress 2.0.6 which fixes this issue
References: http://www.hardened-php.net/advisory_012007.140.html
Overview:
Quote from http://www.wordpress.org
"WordPress was born out of a desire for an elegant, well-
architectured personal publishing system built on PHP and MySQL
and licensed under the GPL. It is the official successor of
b2/cafelog. WordPress is fresh software, but its roots and
development go back to 2001. It is a mature and stable product.
We hope by focusing on user experience and web standards we can
create a tool different from anything else out there."
While testing WordPress it was discovered that there is a XSS
vulnerability in the CSRF protection of WordPress's administration
interface. This might result in a compromise of the admin account
and might result in the execution of arbitrary PHP code.
Details:
The administration interface within WordPress comes with a token
based CSRF protection. When a request is received with an invalid
token it is not discarded like in many similar applications, but
a warning screen is returned that asks the admin to verify the
action by clicking on a link (that contains a valid token).
Unfortunately there was a bug in the way the request information
(URL variables) was put into the new link. Due to this fault it
was possible to break out of the HTML string context by embedding
quotes and HTML tags into the names of URL variables.
Due to this is is possible to launch XSS attacks against admin
users currently logged into their WordPress and perform all possible
administrative actions (or simply steal the login cookie).
Depending on the file permissions on the server (for example a
writeable wp-config.php or template file) this can also be
exploited to execute arbitrary PHP code.
Proof of Concept:
The Hardened-PHP Project is not going to release a proof of concept
exploit for this vulnerability.
Disclosure Timeline:
14. November 2006 - Notified security@wordpress.org
05. January 2007 - WordPress 2.0.6 release
05. January 2007 - Public Disclosure
Recommendation:
We strongly recommend to upgrade to WordPress 2.0.6 which also
fixes several other security vulnerabilities not covered by this
advisory.
http://wordpress.org/download/
GPG-Key:
http://www.hardened-php.net/hardened-php-signature-key.asc
pub 1024D/0A864AA1 2004-04-17 Hardened-PHP Signature Key
Key fingerprint = 066F A6D0 E57E 9936 9082 7E52 4439 14CC 0A86 4AA1
Copyright 2007 Stefan Esser. All rights reserved.
- -----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.3 (GNU/Linux)
iD8DBQFFnnflRDkUzAqGSqERAj0FAJ90O0DfF6ETzPOepDmSmERA34OoqwCeIgSP
hGSWX194r0vFm40tMaUc4bQ=
=R3/p
- -----END PGP SIGNATURE-----
- --------------------------END INCLUDED TEXT--------------------
You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.
NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members. As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.
NOTE: This is only the original release of the security bulletin. It may
not be updated when updates to the original are made. If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.
Contact information for the authors of the original document is included
in the Security Bulletin above. If you have any questions or need further
information, please contact them directly.
Previous advisories and external security bulletins can be retrieved from:
http://www.auscert.org.au/render.html?cid=1980
If you believe that your computer system has been compromised or attacked in
any way, we encourage you to let us know by completing the secure National IT
Incident Reporting Form at:
http://www.auscert.org.au/render.html?it=3192
===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072
Internet Email: auscert@auscert.org.au
Facsimile: (07) 3365 7031
Telephone: (07) 3365 4417 (International: +61 7 3365 4417)
AusCERT personnel answer during Queensland business hours
which are GMT+10:00 (AEST).
On call after hours for member emergencies only.
===========================================================================
-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967
iQCVAwUBRaw/8yh9+71yA2DNAQL33gP+PY009o7dZqyeXQ0xJEAr5y8LMnckghvz
sQI7WGIMr+a8VNpMzxALV+DIFSKnlRQKR2SUXjrjGI51nzVNDZlu39eOeUlGRJ27
KVW3tD7KtF05jZNzyckeLkri691CkePSEguskLdjpSy3v/VhFRucVONK1eLGGVu4
P3S3mMrT/F4=
=9IhY
-----END PGP SIGNATURE-----