Software Engineering Institute

Notified:  May 08, 2007 Updated: July 13, 2007

Status

Affected

Vendor Statement

We have released fixed packages for this problem and issued a notice in http://www.novell.com/linux/security/advisories/2007_13_sr.html

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Notified:  May 08, 2007 Updated: August 22, 2007

Status

Affected

Vendor Statement

Sun can confirm that Solaris 8, 9, and 10 are affected by the issue described in CERT advisory VU#684664

Sun has published Sun Alert 102987 which includes details of the Solaris specific impact, contributing factors, workaround options and resolution information, and is available here:

http://sunsolve.sun.com/search/document.do?assetkey=1-26-102987-1

The Sun Alert will be kept up to date regarding progress on this issue.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Notified:  May 07, 2007 Updated: May 16, 2007

Status

Affected

Vendor Statement

A grayscale PNG image with a malformed (bad CRC) tRNS chunk will crash some libpng applications.

This vulnerability could be used to crash a browser when a user tries to view such a malformed PNG file. It is not known whether the vulnerability could be exploited otherwise.

The reason is that png_ptr->num_trans is set to 1 and then there is an error return after checking the CRC, so the trans[] array is never allocated. Since png_ptr->num_trans is nonzero, libpng tries to use the array later.

This bug was first introduced in libpng version 0.90, in 1996. All versions from libpng-0.90 through libpng-1.2.16 are vulnerable.

Here is the fix, thanks to Mats Palmgren:

--- pngrutil.c_1.2.16 2007-05-11 23:11:55.395466000 -0500
+++ pngrutil.c 2007-05-14 04:37:32.101297000 -0500
@@ -1314,7 +1314,10 @@
}

if (png_crc_finish(png_ptr, 0))
+ {
+ png_ptr->num_trans = 0;
return;
+ }

png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
&(png_ptr->trans_values));

This patch can be applied to any vulnerable version of libpng.

Libpng version 1.0.25 and 1.2.17, which are being released concurrently
with this advisory, have been patched.

This vulnerability has been assigned the identifiers
CVE-2007-2445 and CERT VU#684664.

Glenn Randers-Pehrson
PNG Development Group

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Addendum

See http://www.mirrorservice.org/sites/download.sourceforge.net/pub/sourceforge/l/li/libpng/libpng-1.2.17-ADVISORY.txt for more details.

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