[oCERT-2008-007] libpoppler uninitialized pointer Jul 07 2008 02:06PM
Andrea Barisani (lcars ocert org)

2008/07/07 #2008-007 libpoppler uninitialized pointer


The poppler PDF rendering library suffers a memory management bug which leads
to arbitrary code execution.

The vulnerability is present in the Page class constructor/destructor. The
pageWidgets object is not initialized in the Page constructor if specific
conditions are met, but it is deleted afterwards in the destructor regardless
of its initialization.

Specific PDF files can be crafted which allocate arbitrary memory to trigger
the vulnerability.

A new poppler version addressing the issue is scheduled to be released on
July 30th according to maintainer.

The following patch fixes the issue:

diff --git a/poppler/Page.cc b/poppler/Page.cc
index b28a3ee..72a706b 100644
--- a/poppler/Page.cc
+++ b/poppler/Page.cc
@@ -230,7 +230,7 @@ GBool PageAttrs::readBox(Dict *dict, char *key, PDFRectangle *box) {

Page::Page(XRef *xrefA, int numA, Dict *pageDict, PageAttrs *attrsA, Form *form) {
Object tmp;
+ pageWidgets = NULL; //Security fix
ok = gTrue;
xref = xrefA;
num = numA;

Affected version:

poppler <= 0.8.4

Fixed version:

poppler, N/A

Credit: vulnerability report, patch and PoC code received from Felipe Andres
Manzano <fmanzano [at] fceia [dot] unr [dot] edu [dot] ar>.

CVE: CVE-2008-2950

2008-06-27: vulnerability report received
2008-06-28: contacted poppler maintainers and affected vendors
2008-06-30: maintainer confirms issue and patch
2008-07-07: advisory release




Andrea Barisani | Founder & Project Coordinator
oCERT | Open Source Computer Emergency Response Team

<lcars (at) ocert (dot) org [email concealed]> http://www.ocert.org
0x864C9B9E 0A76 074A 02CD E989 CE7F AC3F DA47 578E 864C 9B9E
"Pluralitas non est ponenda sine necessitate"

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