SPIP 3.1: XSS & Host Header Injection

SPIP 3.1: XSS & Host Header Injection

Date: 2016-11-10 10:51:47
Security Advisory – Curesec Research Team

1. Introduction

Affected Product: SPIP 3.1
Fixed in: 3.1.2 / 3.0.23
Fixed Version Link: http://www.spip.net/en_download
Vendor Website: http://www.spip.net/
Vulnerability Type: Reflected & Persistent XSS, Host Header Injection, httpOnly Cookie disclosure
Remote Exploitable: Yes
Reported to vendor: 09/05/2016
Disclosed to public: 11/10/2016
Release mode: Coordinated Release
CVE: n/a
Credits Tim Coen of curesec GmbH

2. Overview

SPIP is a content management system written in PHP. In version 3.1, it is vulnerable to a persistent as well as reflected cross site scripting vulnerability as it allows users to enter URLs containing the JavaScript protocol, which an attacker can exploit to steal cookies, inject JavaScript keylogger, or bypass CSRF protection. Additionally, it contains a Host Header Injection which may lead to the leakage of password reset tokens and thus the compromisation of user accounts. Finally, the application discloses httpOnly cookies, making exploitation of XSS issues slightly easier.

3. Details

Persistent XSS

CVSS: Medium 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Description: When posting a message in the internal Forum, user input is properly encoded, thus disallowing XSS. However, a hypertext link may be added as well, and there is no check on the protocol of the supplied link, which leads to an XSS vulnerability.

Proof of Concept:

1. Create a new Message: http://localhost/spip/ecrire/?exec=forum&repondre=new 2. In the URL field enter: javascript:alert(1) 3. Post the Message To trigger the payload, a click on the link is required.

Reflected XSS

CVSS: Low 2.6 AV:N/AC:H/Au:N/C:N/I:P/A:N

Description: When editing a private message, a redirect parameter may be submitted as well. This parameter decides to what page a user is returned if they were to press the back button. The value of this parameter is user controlled and may thus be used for phishing or XSS attacks.

Proof of Concept:

Visit: http://localhost/spip/ecrire/?exec=message_edit&new=oui&to=2&redirect=javascript:alert(1) Click on the Back button represented by the envelope icon.

Host Header Injection

CVSS: Low 2.6 AV:N/AC:H/Au:N/C:P/I:N/A:N

The application takes the Host Header and uses it in a password reset email. As the Host Header is user-controlled, an attacker can set it to arbitrary values.

In the case of a password reset page, this can lead to security issues as an attacker can request a password reset email for a user and set the Host header to a server they control. As this header is used in the email, a user would be send to the attackers server if they were to click on the link, leading to the leakage of the recovery token and thus the compromisation of the account.

Proof of Concept:

Request: POST /spip/spip.php?page=spip_pass&lang=en HTTP/1.1 Host: example.com Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate Cookie: spip_accepte_ajax=1; spip_admin=%40admin; PHPSESSID=1l8rvbhcgia45ddj7ldoc1gpf6; wb-installer=3d2hes1b6i0bfb586iucm76sp2; wb-4174-sid=u571gr7isplq8b4f01fniqevk2 Connection: close Upgrade-Insecure-Requests: 1 Content-Type: application/x-www-form-urlencoded Content-Length: 199 page=spip_pass&lang=en&formulaire_action=oubli&formulaire_action_args=orESpF0vSC3Q%2BB30uGEFqT7k6AcDObDMasMNzVp3EjndtlvZ%2B5k4g%2FkyF%2BAlzhBhCI%2F%2F9hx%2FZ33mkQPk&oubli=visitor%40example.com&nobot= Email Send: [My SPIP site] Forgotten password (this is an automated message) To recover your access to the site My SPIP site (http://localhost/spip) Please go to the following address: http://example.com/spip/spip.php?page=spip_pass&p=107017475657c15ad6e9c781.23674073 You can then enter a new password and log in to the site.

httpOnly Cookie Disclosure

Description: The phpinfo page discloses httpOnly cookies such as session cookies, making it slightly easier to exploit XSS vulnerabilities.

Proof of Concept:


4. Solution

To mitigate this issue please upgrade at least to version 3.1.2:


Please note that a newer version might already be available.

5. Report Timeline

09/05/2016 Informed Vendor about Issue
09/23/2016 Vendor releases fix
11/10/2016 Disclosed to public