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Bug #47359 XSS: incorrect mime type for bmp in getimagesize/image_type_to_mime_type()
Submitted: 2009-02-11 11:53 UTC Modified: 2009-03-17 03:29 UTC
Votes:1
Avg. Score:3.0 ± 0.0
Reproduced:1 of 1 (100.0%)
Same Version:0 (0.0%)
Same OS:0 (0.0%)
From: hsudhof at gmail dot com Assigned: scottmac
Status: Closed Package: GetImageSize related
PHP Version: 5.2.9RC1 OS: *
Private report: No CVE-ID:
 [2009-02-11 11:53 UTC] hsudhof at gmail dot com
Description:
------------
For BMP images, image.c contains the mime type "image/bmp".
That mime type does not exist; the proper mime for bmp images is "image/x-ms-bmp".


http://www.iana.org/assignments/media-types/image/

This is a problem, as this opens a XSS vulnerability for users with IE < 8.


The reproduction code shows XSS, when the page is viewed with IE versions earlier than IE8 Beta2.

Reproduce code:
---------------
<?php
$image = 'Qk1eAAAAAAAAAD4AAAAoAAAABwAAAAgAAAABAAEAAAAAACAAAAB0EgAAdDxzY3JpcHQ+YWxlcnQoJ1hTUyBkdWUgdG8gd3JvbmcgaGVhZGVyJyk7PC9zY3JpcHQ+AA==';
$file = base64_decode($image);
file_put_contents('test.bmp', $file);
$image_data = getimagesize('test.bmp');
header("Content-type: {$image_data['mime']}");
// echo "Expected: 'image/x-ms-bmp' ; actual : '{$image_data['mime']}'";
header('Content-disposition: inline; filename="test.bmp"');
readfile('test.bmp');
// unlink('test.bmp');



Expected result:
----------------
Header: "image/x-ms-bmp"

Actual result:
--------------
Header : "image/bmp"; that causes a javascript popup when visiting with IE6 and IE7.

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History

AllCommentsChangesGit/SVN commitsRelated reports
 [2009-02-11 12:44 UTC] scottmac@php.net
This looks like a bug in the IE mime type sniffing rather than a specific XSS.

If I make the mime type image/bm or image/bmps or image/ms-bmp or any of the half dozen that are listed they work correctly.

There is no official IANA mime type for bmp listed on the page so I'll investigate this some more.
 [2009-03-17 03:29 UTC] scottmac@php.net
This bug has been fixed in CVS.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.
 
Thank you for the report, and for helping us make PHP better.

Will be in 5.3+
 
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