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Forensically Invisible Images of Hot Chicks

By  Oct 17, 2007

Topics: Security

When you view an image online, that file is first downloaded to the local PC, where it is cached. Most people are aware of this, which is many keep their cache cleaned out - especially if those images are potentially embarrassing or illegal. Unfortunately, these files are not truly delete, which is why many people get busted with thousands of files once a forensics team gets to the drive.

So, what if it was possible for someone to create a site full of images that you could view in a browser without ever having to worry about left over data on your drive?

Well, it is actually quite easy.

1. Encode each image as base64 using something like this:
$data = chunk_split(base64_encode(file_get_contents('IMAGE.jpg')), 76, "\n");

2. Create an IMG tag and for the src value, enter this:
data:image/gif;base64,<followed by base64 encoded image

3. On your page, place this PHP code at the top:
header("Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0");

The end result is that the data of the image, which is contained within the HTML of the page, will not be cached. Nor will the actual image be cached. If you don't believe us, clear out your cache in Firefox and then open a new tab and type 'about:cache' in the address bar. Then view your hard drive cache and note it is empty. Refresh this page and see if there is any mention of a hotchick. You can see the data in RAM, but once you reboot, that data will disappear.

Now there is a chance that some paging file might end up with the content - but this is probably not going to happen.

The following is the promised base64 encoded image of a few hot chicks.

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