This vulnerability has been published some days ago where an attacker could create a duplicated “admin” user and recover the legitimate “admin” password. SQL column truncation is an attacking technique whereby an attacker take advance of some kind of mismatch between an application and the database structure used by it.
Let’s have a look to the vulnerable code.
In schema.php in the Wordpress application it is defined the creation of the database table containing users:
CREATE TABLE $wpdb->users ( ID bigint(20) unsigned NOT NULL auto_increment, user_login varchar(60) NOT NULL default '',
As we can see, the user_login field has a length of 60 bytes. However, the application does not enforce this limitation and allows longer usernames.
An attacker could create a user called “admin[55 spaces]X”. The last “X” is character 61 and therefore will be ignored by the database.
Later in the code, we can see that the user_login field is trim()ed and all the spaces are removed, so it becomes “admin”:
<?php if ( strstr($_POST['user_login'], '@') ) { $user_data = get_user_by_email(trim($_POST['user_login'])); if ( empty($user_data) ) $errors->add('invalid_email', __('<strong>ERROR</strong>: There is no user registered with that email address.')); } else { $login = trim($_POST['user_login']); $user_data = get_userdatabylogin($login); ?>
In summary, this is a very creative vulnerability and an interesting vector of attack.
[1]: http://irk4z.wordpress.com/2008/09/14/sql-column-truncation-vulnerability/
Over the last year however I have been very fortunate to have the opportunity to go to some of the smaller, but by no means less valuable, conferences around Europe and they have been awesome. They have all been well organised, with a great atmosphere and some incredible talks.
See more
SECFORCE presented security issues affecting Internet banking applications.
See moreThank you!
Please try again later.
