[Forum] "Invalid URL" when uploading an Image

[Th3Dan]

Hello,

every time when we want to upload an image using a direct-link the error "Invalid URL" apprears. I tried this with different links and imagehosters, not at least one worked. The links are directlinks to an jpg/png image like http://abload.de/img/color_icon_blue.svga4pz0.png so that they're definitely valid.

Steps to reproduce:
1. Open a Thread and go to the editor in the "direct reply" field on the bottom of the page
2. Click on the Image-Icon with hover-text "Insert graphics"
3. Switch to the tab "from a URL" and insert a valid URL to an image like the one above
4. Make sure that the checkbox "Load graphics from a URL and save it to the forum" is checked and click OK
5. Now an alert-box appears with the content "error: Invalid URL" With the attachment-manager in the advanced editor its the same, after uploading I get an alert-box with "http://abload.de/img/color_icon_blue.svga4pz0.png: Invalid URL".

Environment-Information:
Webserver: IIS 8.5 using the latest and stable PHP 5.4-Release (5.4.41) with CURL-Extension
vBulletin 4.2.2 PL 4

Thinks I already tried:
- Using different URLs
- Disable all hooks so that plugins can't be causing this issue
- Took a look in the sourcecode of attachment.php and related classes/librarys like the attachment-package to find out where this error is thrown
- Different themes

It had no effect, I spend hours on trying so solve this problem and it's still not possible to upload images by URLs as attachment. For me this seems like a bug in vBulletin - maybe caused by a PHP-Update, because in the past this function worked like expected. The vB-Team can PN me for the link to my board. Please note that my vB-Installation is in German, so the error-message is analogously translated from English to German, but I think this should not be a big issue here.

[KurtinSA]

I went through your steps...a little different for me, but basically the same thing. The URL you referenced shows up fine in a forum post. We're running on a Linux server; we also have 4.2.2 PL4 but our PHP is 5.5.21-1~dotdeb.1.

I don't have any suggestions...just wanted to try and report my situation.

Kurt

[Wayne Luke]

The server you're trying to obtain the image from may have leech and hotlink protection. So while it works from your browser, it may not work when your server performs the same connection.

[jdj]

The server you're trying to obtain the image from may have leech and hotlink protection. So while it works from your browser, it may not work when your server performs the same connection.

I often get a similar error message in 5.1.7 when trying to upload a file from my c: drive (PC) to my server (Linux). No idea why.

PS: That's on the CMS.

[Wayne Luke]

If you open a problem image in a text editor like Notepad++, what are the first 100 characters? What type of image is it? What is the filename of the image?

[jdj]

They are usually JPGs. What's the significance of opening in a text editor/first 100 characters? I'll try this next time I see the problem but what am I looking for?

[Wayne Luke]

Two reasons...

First, to make sure they are actually the image type they say they are. People often just use whatever extension they are familiar with. When people complained that images weren't showing up, the browser companies decided to ignore the extension and just look inside and use that image algorithm. This brings us to the second issue. JPG files and some other files are vulnerable to exploitation. Code can be inserted into the image without breaking the image itself. We check for this so your server doesn't get compromised.

So if someone uploads a GIF file with a JPG extension, we reject it as invalid. If the comments inside a JPG are problematic, we reject it.