Unauthenticated stored XSS affecting admins in 404-to-301<2.3.1

DESCRIPTION.md

Description

There is a stored XSS in the 404-to-301 WP plugin<2.3.1. Unauthenticated users can visit a specially crafted URL and the redirect path will be logged to the database. The redirection source is stored unescaped in the database, thus it is served as-is and evaluated in the browsers of logged-in admins when they check the redirection logs on http://wordpress/wp-admin/admin.php?page=i4t3-logs. Affected versions are <2.3.1.

POC

A similar requests must be sent to the vulnerable server. Make sure to request a page serving a 404, ie by requesting a post with an unexisting post ID.

GET /?p=99999999999999999929"><script>alert(document.cookie)</script> HTTP/1.1
Host: wordpress
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8
Connection: close

Patch

https://github.com/joel-james/404-to-301/commit/7a4e2798eca79828c1611988289e06b6d9c18b61

Timeline

08/25/16 Contacted maintainer via email
08/26/16 Maintainer acknowledges the bug
08/27/16 Maintainer releases patch

Hi guys,

I have pushed an update now. Fixed another issue remained in Referral field.

@panvagenas:

payload still is executed when loading the Custom Redirect edit dialog

Can you explain a bit more clearly? I couldn't see anything. I have added url escaping in custom redirect too.