Miscellaneous Hacks - Patched Flash Uploader to Fix Known Exploits

UPDATE Dec 2014: 4.2.2 PL2, 4.2.2 PL3 and 4.2.3 core download packages from vBulletin now include this patched version of uploader.swf as standard.

This is a patched version of YUI 2.9.0 uploader.swf as used by vBulletin 4.x for managing multiple file uploads.

An exploit was found in the flash uploader (uploader.swf) file supplied with vBulletin 4.x. This file is part of the Yahoo YUI 2 Library which is end of life and Yahoo have stated that they will not be fixing it. Yahoo recommends that the file is removed as the flash uploader has been deprecated.

vBulletin's recommended fix is to replace the file with an empty file of the same name. If you do this, however, and rely solely on the Ajax uploader you will not be able to select multiple files without further modifications.

This modification is a recompiled version of uploader.swf with the above exploit fixed. An additional potential exploit has also been fixed by disabling a parameter not used by vBulletin.

The YUI source used is provided freely by Yahoo to whom I give full credit.


1) Installation

a) Extract uploader.swf from the .zip file and replace your existing file here:

<forum_root>/clientscript/yui/uploader/assets/uploader.swf

b) Make sure the flash uploader is enabled in the Admin Control Panel

Options -> Message Attachment Options -> Asset Manager - Enable -> Select "Yes, Flash Upload by Default"

c) Make sure you are NOT using remote YUI

vBulletin Options -> Server Settings and Optimization Options

Use Remote YUI set to None

d) You may also need to clear your browser cache and/or vBulletin cache (Maintenance ->Clear system cache) if you have performed the above steps correctly but clicking the Upload button still does nothing.



2) Changes

11th January 2014

The parameter 'allowedDomain' has been sanitised with a REGEX to prevent malicious javascript being passed in a query string.


11th January 2014 v2

Many thanks to FranzBanz (http://www.vbulletin.com/forum/member/449383-franzbanz) for his suggestions

• finding another exploit (using another parameter). Exploit fixed by setting the parameter (not used by vBulletin) to null.
• '-' Character added to allowed characters in allowedDomain

Non-Flash Alternative
Please note that if you would rather avoid using flash altogether an alternative Mod has been released by BirdOPrey5, although there are some compromises/limitations with IE10+.

Asset Manager / Image Upload Fix to upload multiple files like the Flash uploader


DISCLAIMER
I am not a flash developer, I am just another vBulletin customer trying to keep his members happy!
This file is provided free of charge for the benefit of the vBulletin community. You use it at your own risk!


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[Thangvip9x]

Working on vBulletin 4.2.2, thank you very much

[Rebecca217]

Thank you so much for taking the time to fix this, and to make it available to the rest of us!

[migratoria]

Tanks for the fix!

[SomeSailor]

This should be included as a patch to all VB installs. Thank you very much!

[tpearl5]

This should definitely be included as a patch! Thanks!

[migratoria]

In vb 4.2.2 works...

[rootsxrocks]

Thank you

[Phaedrus]

Cool. Let's see if anybody at my site notices.

[BarracodE]

Thank you so much. This issue was difficult to track down. Multiple images is very important to our users. Clearing the browser cache was the final missing piece. Thank you!

[Jaydee 2]

Many thanks for this fix. It was an good idea!

I'll install it approximately in just one forum (just for testing it) and maybe later on in all the remaining ones.