oss-security - Heap overflow / invalid read in Libtasn1 before 4.5 (TFPA 005/2015)

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Date: Thu, 30 Apr 2015 14:46:42 +0200
From: Hanno Böck <hanno@...eck.de>
To: oss-security@...ts.openwall.com, fulldisclosure@...lists.org,
  cve-assign@...re.org
Subject: Heap overflow / invalid read in Libtasn1 before 4.5 (TFPA 005/2015)

https://blog.fuzzing-project.org/9-Heap-overflow-invalid-read-in-Libtasn1-TFPA-0052015.html

While fuzzing GnuTLS I discovered a malformed certificate input sample
that would cause a heap overflow read of 99 bytes in the DER decoding
functions of Libtasn1. The heap overflow happens in the function
_asn1_extract_der_octet().

This issue was reported to the Libtasn1 developer on 16th April. A fix
was committed on 20th April and is part of the Libtasn1 4.5 release.
This issue was found with american fuzzy lop and address sanitizer.

http://git.savannah.gnu.org/gitweb/?p=libtasn1.git;a=commitdiff;h=f979435823a02f842c41d49cd41cc81f25b5d677
Git commit / fix

https://lists.gnu.org/archive/html/help-libtasn1/2015-04/msg00000.html
Libtasn1 4.5 release notes

https://crashes.fuzzing-project.org/TFPA-2015-005-libtasn1-4.4-heap-overflow.crt
Sample malformed certificate exposing heap overflow (test with
certtool -i --inder --infile=[sample] and address sanitizer or
valgrind)

-- 
Hanno Böck
http://hboeck.de/

mail/jabber: hanno@...eck.de
GPG: BBB51E42

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