OctoberCMS 1.0.425 (Build 425) - Cross-Site Scripting

# Exploit Title: OctoberCMS 1.0.425 (aka Build 425) Stored XSS
# Vendor Homepage: https://octobercms.com/
# Software Link: https://octobercms.com/download
# Exploit Author: Ishaq Mohammed ( https://www.exploit-db.com/author/?a=9086)
# Contact: https://twitter.com/security_prince
# Website: https://about.me/security-prince
# Category: webapps
# CVE: CVE-2017-15284

1. Description

Cross-Site Scripting exists in OctoberCMS 1.0.425 (aka Build 425), allowing
a least privileged user to upload an SVG file containing malicious code as
the Avatar for the profile. When this is opened by the Admin, it causes
JavaScript execution in the context of the Admin account.

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-15284

2. Proof of Concept

Steps to Reproduce:

   - Login using a normal user and click on my account.
   - Click on the avatar.
   - Upload the malicious .svg file which contains the javascript
   - Click on save.
   - Login in another browser with Admin Credentials.
   - Click on Settings > Administrators.
   - Select the normal user's avatar and click on Attachment URL.

3. Reference

https://securityprince.blogspot.fr/2017/10/cve-2017-15284-octobercms-10425-build.html
https://github.com/octobercms/library/commit/3bbbbf3da469f457881b5af902eb0b89b95189a2

4. Solution

The vulnerability will be patched by the vendor in the next release of
OctoberCMS.

-- 
Best Regards,
Ishaq Mohammed
https://about.me/security-prince