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!


Copyright ? 2013 Yahoo! Inc. All rights reserved.
Redistribution and use of this software in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

Neither the name of Yahoo! Inc. nor the names of YUI's contributors may be used to endorse or promote products derived from this software without specific prior written permission of Yahoo! Inc.

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[K!nG]

Originally Posted by Zachery

You can't use a REMOTE YUI, you have to use a local one. The SWF uploader on google/yahoo's servers have been removed.

So basically this means i should upload the attached file and change it to local and it should work or should i just upload the empty file and change it to local ???

[K!nG]

Originally Posted by Zachery

You can't use a REMOTE YUI, you have to use a local one. The SWF uploader on google/yahoo's servers have been removed.

Hi Zachery,

Even after selecting NONE i am still not able to get it done. When i click on "Insert image" nothing happens.

[Zachery]

What browser?

[K!nG]

Using google chrome.

[K!nG]

Since u asked for browser , I just checked it in IE and it's working fine. I only use chrome and it was working fine, but all of sudden it's not.

[Toorak Times]

For some reason a lot of my plugins will not even appear in Google Chrome but appear in Firefox and Safari no probs

[rharbison]

Update - The problem seems to be in VB 4.2.2 itself, even when using the 0 byte version of Uploader.swf, the problem still exists.

VB 4.2 PL 1 seems to have broken this. With the modified version of uploader.swf, the images SEEM to work. While editing your message they show up in the post just fine. However... When you save the message, you only get a link to the attachment, not the image.

Anyone else seeing this? Anyone got a solution?

[alexm]

Originally Posted by K!nG

Since u asked for browser , I just checked it in IE and it's working fine. I only use chrome and it was working fine, but all of sudden it's not.

a) Upload the modified SWF file and 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"

b) vBulletin Options -> Server Settings and Optimization Options

Use Remote YUI set to None

c) Close your forum page and clear your browser cache - a lot of the issues where clicking the upload button does nothing is due to browser caching issues

Hopefully this helps!

[alexm]

Originally Posted by rharbison

Update - The problem seems to be in VB 4.2.2 itself, even when using the 0 byte version of Uploader.swf, the problem still exists.

VB 4.2 PL 1 seems to have broken this. With the modified version of uploader.swf, the images SEEM to work. While editing your message they show up in the post just fine. However... When you save the message, you only get a link to the attachment, not the image.

Anyone else seeing this? Anyone got a solution?

I can't replicate this I'm afraid. I'm using 4.2.2 PL1 too and everything seems to work just fine. I'm using the standard, unmodified editor with asset manager and attachments work both via asset manager and in quick reply.

[rharbison]

OK, so here's the odd thing. I run about 6 forums (yes, all licensed). All are, as far as I know, the same. All are running V 4.2.2 PL1. One of the forums is having a problem with the attachments not showing up inline. It's reproducible, but also somewhat random.