Topic awaiting preservation: Dynamic Images?

Ok i've been hearing for a while that there is several security risks in allowing dynamic images on forums.
some forums don't allow them at all for that reason.

I'm having trouble figuring out why? What are the (in any) dangers in that?

Like say I wanted to use

[ IMG ] [url=http://www.site.com/image.php?img.gif]http://www.site.com/image.php?img.gif[/url]  [ /IMG ]

or something to that general effect to rotate images...

is there any danger of someone being able to load a remote script though that or something? if not then what's all the fuss about? Sorry if it seems like a newbie question, but it's been bugging me for a while lol

(edit = had to add spaces, darn thing kept trying to parse an image even inside the code tags err.....)

[This message has been edited by Synthetic (edited 09-22-2002).]

I can't think of anything.
If it is in an image tag, and the browser can't register it as one of its recognized formats, it usually just doesn't render it.

maybe if they did something like http://www.site.com/image.php?../../etc/passwd

I remember a while ago a post had some links to articles explaining how you can prevent things like this happening in php. I think the exploits were more like initializing a variable in the script and that this wouldn't happen if you used local variables instead of global.

The poster has demanded we remove all his contributions, less he takes legal action.
We have done so.
Now Tyberius Prime expects him to start complaining that we removed his 'free speech' since this message will replace all of his posts, past and future.
Don't follow his example - seek real life help first.

InI: Alarmism is a good reaction to the slack security of the majority of us

These issues have come up before so I started a FAQ on PHP security issues:

What are the security problems with using PHP and how can I fix them?

___________________
Emps

FAQs: Emperor

thanks guys most informative