SPIP 3.1.2 Server Side Request Forgery

`## SPIP 3.1.2 Server Side Request Forgery (CVE-2016-7999)  
  
### Product Description  
  
SPIP is a publishing system for the Internet, which put importance on collaborative working, multilingual environments and ease of use. It is free software, distributed under the GNU/GPL licence.  
  
### Vulnerability Description  
  
It's possible to send HTTP/FTP requests using the `valider_xml` file.  
Attackers can make it look like the server is sending the request, possibly bypassing access controls such as a firewall that would prevent the attacker from accessing the URLs directly.  
  
**Access Vector**: remote  
  
**Security Risk**: medium  
  
**Vulnerability**: CWE-918  
  
**CVSS Base Score**: 5.5 (Medium)  
  
**CVE-ID**: CVE-2016-7999  
  
### Proof of Concept  
  
http://spip-dev.srv/ecrire/?exec=valider_xml&var_url=http://router-dev.srv/  
http://spip-dev.srv/ecrire/?exec=valider_xml&var_url=ftp://ftp.debian.org/  
  
  
### Vulnerable code  
  
The FTP connection is initialized by the `is_dir` function inside `valider_xml`, line 79 :  
  
if (is_dir($url)) {  
  
Other PHP Wrappers supporting `is_dir` can be called using this function.  
  
The HTTP connection is initiated at line 123:  
  
$res = $transformer_xml(recuperer_page($url));  
  
### Timeline (dd/mm/yyyy)  
  
* 15/09/2016 : Initial discovery  
* 26/09/2016 : Contact with SPIP Team  
* 27/09/2016 : Answer from SPIP Team, sent advisory details  
* 27/09/2016 : Server Side Request Forgery vulnerability correct vulnerabilities.  
* 30/09/2016 : SPIP 3.1.3 Released  
  
### Fixes  
  
* https://core.spip.net/projects/spip/repository/revisions/23188  
* https://core.spip.net/projects/spip/repository/revisions/23193  
  
### Affected versions  
  
* Version <= 3.1.2  
  
### Credits  
  
* Nicolas CHATELAIN, Sysdream (n.chatelain -at- sysdream -dot- com)  
  
  
--   
SYSDREAM Labs <[email protected]>  
  
GPG :  
47D1 E124 C43E F992 2A2E  
1551 8EB4 8CD9 D5B2 59A1  
  
* Website: https://sysdream.com/  
* Twitter: @sysdream  
  
  
  
  
  
  
  
  
  
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