1.1 什么是暴力破解攻击？ 连续性尝试 字典 自动化
一个有效是字典，可以大大提高暴力破解的效率
常用的账号密码（弱口令），比如常用用户名/密码TOP 500等。 互联网上被脱裤后账号密码（社工库），比如CSDN当年泄露的约600w用户信息。 使用指定的字符使用工具按照指定的规则进行排列组合算法生成密码。
脱库 :是指黑客入侵有价值的网络站点，把注册用户的资料数据库全部盗走的行为。
撞库 :是黑客通过收集互联网已泄露的用户和密码信息，生成对应的字典表，尝试批量登陆其他网站后，得到一系列可以登录的用户。很多用户在不同网站使用的是相同的账号密码，因此黑客可以通过获取用户在A网站的账户从而尝试登录B网址，这就可以理解为撞库攻击。
如果一个网站没有对登录接口实施暴力破解的措施，或者实施了不合理的措施。则称该网站存在暴力破解漏洞。
是否要求用户设置了复杂的密码？ 是否每次认证都使用安全的验证码？ 是否对尝试登陆的行为进行判断和限制？ 是否在必要的情况下采用了双因素认证？
存在暴力破解漏洞的网站可能会遭受暴力破解，但是成功的可能性并不是100%！所以有些网站即使存在暴力破解漏洞，但其管理员可能会忽略它的危害。
但作为一个搞安全的，我们应该在系统设计的时候，就应该将这些措施加入到对应的认证场景中，绝不能为了妥协开发人员或者是业务人员，有半点侥幸心理，否则被干的就是你了！
①确认登录接口的脆弱性
② 对字典进行优化
③工具自动化操作
技巧一、
技巧二、
实验环境：pikachu
抓包——》字典攻击
CAPTCHA,“Completely Automated Public Turing test to tell Computers and Humans Apart”
全自动区分计算机和人类的公开图灵测试（英语：Completely Automated Public Turing test to tell Computers and Humans Apart，简称CAPTCHA），俗称验证码，是一种区分用户是机器或人类的公共全自动程序。在CAPTCHA测试中，作为服务器的计算机会自动生成一个问题由用户来解答。这个问题可以由计算机生成并评判，但是必须只有人类才能解答。由于机器无法解答CAPTCHA的问题，回答出问题的用户即可视为人类。
1、登录暴力破解
验证码可以防止暴力破解，但是你的验证码安全嘛？
查看一下源码：E:\XAMPP\htdocs\pikachu\vul\burteforce\bf_client.php
1、使用前端js实现验证码（纸老虎）；
1、验证码在后台不过期，导致可以长期被使用；
验证码没过期
1、设计安全的验证码（安全带流程 复杂而又可用的图形）
<?php
/**
* Created by runner.han
* There is nothing new under the sun
*/
$PIKA_ROOT_DIR = "../../";
include_once $PIKA_ROOT_DIR.'inc/config.inc.php';
include_once $PIKA_ROOT_DIR.'inc/mysql.inc.php';
include_once $PIKA_ROOT_DIR.'inc/function.php';
$SELF_PAGE = substr($_SERVER['PHP_SELF'],strrpos($_SERVER['PHP_SELF'],'/') 1);
if ($SELF_PAGE = "bf_client.php"){
$ACTIVE = array('','active open','','','','','active',"","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","");
}
include_once $PIKA_ROOT_DIR.'header.php';
$link=connect();
$html="";
if(isset($_POST['submit']) && $_POST['username'] && $_POST['password'] && $_POST['token']){
$username = $_POST['username'];
$password = $_POST['password'];
$token = $_POST['token'];
$sql = "select * from users where username=? and password=md5(?)";
$line_pre = $link->prepare($sql);
$line_pre->bind_param('ss',$username,$password);
if($token == $_SESSION['token']){
if($line_pre->execute()){
$line_pre->store_result();
if($line_pre->num_rows>0){
$html.= '<p> login success</p>';
} else{
$html.= '<p> username or password is not exists～</p>';
}
}else{
$html.= '<p>执行错误:'.$line_pre->errno.'错误信息:'.$line_pre->error.'</p>';
}
}else{
$html.= '<p> csrf token error</p>';
}
}
//生成token
set_token();
?>
<div class="main-content" xmlns="http://www./1999/html">
<div class="main-content-inner">
<div class="breadcrumbs ace-save-state" id="breadcrumbs">
<ul class="breadcrumb">
<li>
<i class="ace-icon fa fa-home home-icon"></i>
<a href="burteforce.php">暴力破解</a>
</li>
<li class="active">token防爆破?</li>
</ul><!-- /.breadcrumb -->
<a href="#" style="float:right" data-container="body" data-toggle="popover" data-placement="bottom" title="tips(再点一下关闭)"
data-content="token了解下,后面搞CSRF会用到....虽然这里并没有什么鸟用.">
点一下提示~
</a>
</div>
<div class="page-content">
<div class="bf_form">
<div class="bf_form_main">
<h4 class="header blue lighter bigger">
<i class="ace-icon fa fa-coffee green"></i>
Please Enter Your Information
</h4>
<form id="bf_client" method="post" action="bf_token.php" ">
<!-- <fieldset>-->
<label>
<span>
<input type="text" name="username" placeholder="Username" />
<i class="ace-icon fa fa-user"></i>
</span>
</label>
</br>
<label>
<span>
<input type="password" name="password" placeholder="Password" />
<i class="ace-icon fa fa-lock"></i>
</span>
</label>
</br>
<input type="hidden" name="token" value="<?php echo $_SESSION['token'];?>" />
<label><input class="submit" name="submit" type="submit" value="Login" /></label>
</form>
<?php echo $html;?>
</div><!-- /.widget-main -->
</div><!-- /.widget-body -->
</div><!-- /.page-content -->
</div>
</div><!-- /.main-content -->
<?php
include_once $PIKA_ROOT_DIR.'footer.php';
?>
好博客要分享O(∩_∩)O哈哈~：https:///posts/30313.html#toc-heading-1
来源：https://www./content-4-796751.html
