Related Weaknesses
CWE-ID |
Weakness Name |
Source |
CWE-89 |
Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection') The product constructs all or part of an SQL command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended SQL command when it is sent to a downstream component. Without sufficient removal or quoting of SQL syntax in user-controllable inputs, the generated SQL query can cause those inputs to be interpreted as SQL instead of ordinary user data. |
|
Metrics
Metrics |
Score |
Severity |
CVSS Vector |
Source |
V2 |
6.8 |
|
AV:N/AC:M/Au:N/C:P/I:P/A:P |
[email protected] |
EPSS
EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.
EPSS Score
The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.
EPSS Percentile
The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.
Exploit information
Exploit Database EDB-ID : 4721
Publication date : 2007-12-10 23h00 +00:00
Author : Abel Cheung
EDB Verified : Yes
=== WordPress Charset SQL Injection Vulnerability ===
Release date: 2007-12-10
Last modified: 2007-12-12
Source: Abel Cheung <abelcheung at gmail dot com>
Affected version: WordPress <= 2.3.1
Exploit type: Remote
Risk: Moderate
CVE: pending
Reference: http://www.abelcheung.org/advisory/20071210-wordpress-charset.txt
1. Summary
2. Detail
3. Proof of concept
4. Workaround
1. Summary
Quoting from http://wordpress.org/:
WordPress is a state-of-the-art semantic personal publishing platform
with a focus on aesthetics, web standards, and usability.
What a mouthful. WordPress is both free and priceless at the same time.
It is found that the search function provided within WordPress fails to
sanitize input based on different character sets. So if WordPress tries
to query MySQL database using certain specific character sets, WordPress
search function is exploitable using charset-based SQL injection.
Currently known character sets exploitable include Big5 and GBK.
All of them may use backslash ('\') as part of multibyte character.
WordPress with MySQL database created any other character sets fulfilling
such property may also be exploitable.
Executing this attack alone results in exposure of all database
content on web interface without need of authentication. However, if
combined with other exploits (such as cookie authentication vulnerability
in http://www.cl.cam.ac.uk/~sjm217/advisories/wordpress-cookie-auth.txt),
any remote user can obtain WordPress admin privilege, resulting in server
compromise.
2. Detail
Most database query in WordPress uses escape() method to sanitize SQL
string, which is essentially filtering input via addslashes() function.
However addslashes() fails to consider character set used in SQL string,
and blindly inserts backslash before any single quote, regardless of
whether such backslashes will form another valid character or not.
In proof of concept used in this advisory, two bytes 0xB327 is
injected into search variable. After escaping string with escape(),
a backslash (0x5C) is inserted before single quote (0x27), thus becoming
0xB35C27. However 0xB35C is a valid Big5 multibyte character,
leaving the single quote behind, so SQL injection occurs. The same
multibyte character is also valid under GBK encoding.
Inside SQL statement used within proof of concept, MD5 hashes of all
users' passwords are selected from database, and presented as post
title. With suitable SQL statement, any database field can be dumped
in similar way.
Currently it is known that WordPress search function uses this
insufficient method to sanitize database query. Possibly other
database queries utilizing same method to filter user input can be
equally susceptible.
However, note that WordPress sites using such character sets is not
very common, since most default installation uses either latin1 or utf8
character set. Asian sites, in particular Chinese ones, are more likely
vulnerable.
Although all WordPress versions before 2.3.1 are vulnerable, only
WordPress 2.2 or above allows changing database query character set
via WordPress configuration file (wp-config.php). For all versions
below 2.2, modifying MySQL configuration to use those character sets
is needed for exploit to be functional. The setting of WordPress HTML
character set (adjustable within WordPress admin page) is irrelevant.
Relevant code is listed below. In wp-includes/query.php:
// If a search pattern is specified, load the posts that match
if ( !empty($q['s']) ) {
......
foreach((array)$q['search_terms'] as $term) {
$term = addslashes_gpc($term);
......
}
addslashes_gpc() is defined in wp-includes/formatting.php:
function addslashes_gpc($gpc) {
......
return $wpdb->escape($gpc);
}
Finally, escape() method belongs to wp-includes/wp-db.php:
function escape($string) {
return addslashes( $string ); // Disable rest for now, causing problems
......
}
3. Proof of concept
a. After WordPress installation, modify wp-config.php to make sure
it uses certain character set for database connection (Big5 can also be used):
define('DB_CHARSET', 'GBK');
b. http://localhost/wordpress/index.php?exact=1&sentence=1&s=%b3%27)))/**/AND/**/ID=-1/**/UNION/**/SELECT/**/1,2,3,4,5,user_pass,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24/**/FROM/**/wp_users%23
4. Workaround
Note: This vulnerability only exists for database queries performed
using certain character sets. For databases created in most other
character sets no remedy is needed.
a. It is recommended to convert WordPress database to use character sets not
vulnerable to such SQL exploit. One such charset is UTF-8, which does not
use backslash ('\') as part of character and it supports various languages.
Even if database charset conversion is inconvenient or impossible, use UTF-8
as DB_CHARSET setting to avoid sending query using vulnerable multibyte charset.
b. Alternatively, modify WordPress core (query.php) to remove search capability.
ChangeLog:
- 2007-12-12
* Modify workaround (thanks to Florian Sander for suggestion)
# milw0rm.com [2007-12-11]
Products Mentioned
Configuraton 0
Wordpress>>Wordpress >> Version 2.0
Wordpress>>Wordpress >> Version 2.0.1
Wordpress>>Wordpress >> Version 2.0.2
Wordpress>>Wordpress >> Version 2.0.3
Wordpress>>Wordpress >> Version 2.0.4
Wordpress>>Wordpress >> Version 2.0.5
Wordpress>>Wordpress >> Version 2.0.6
Wordpress>>Wordpress >> Version 2.0.7
Wordpress>>Wordpress >> Version 2.0.10
Wordpress>>Wordpress >> Version 2.0.10_rc1
Wordpress>>Wordpress >> Version 2.0.10_rc2
Wordpress>>Wordpress >> Version 2.1.1
Wordpress>>Wordpress >> Version 2.1.2
Wordpress>>Wordpress >> Version 2.1.3
Wordpress>>Wordpress >> Version 2.1.3_rc1
Wordpress>>Wordpress >> Version 2.1.3_rc2
Wordpress>>Wordpress >> Version 2.2
Wordpress>>Wordpress >> Version 2.2.1
Wordpress>>Wordpress >> Version 2.2.2
Wordpress>>Wordpress >> Version 2.2.3
Wordpress>>Wordpress >> Version 2.2_revision5002
Wordpress>>Wordpress >> Version 2.2_revision5003
Wordpress>>Wordpress >> Version 2.3
Wordpress>>Wordpress >> Version 2.3.1
References