Bug 1377926 – CVE-2016-8687 libarchive: stack based buffer overflow in bsdtar_expand_char (util.c)

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Bug 1377926 - (CVE-2016-8687) CVE-2016-8687 libarchive: stack based buffer overflow in bsdtar_expand_char (util.c)

Summary:	CVE-2016-8687 libarchive: stack based buffer overflow in bsdtar_expand_char (...

Status:	CLOSED WONTFIX

Aliases:	CVE-2016-8687

Product:	Security Response
Classification:	Other
Component:	vulnerability (Show other bugs)
Sub Component:
Version:	unspecified
Hardware:	All Linux

Priority	low Severity low
Target Milestone:	---
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Assigned To:	Red Hat Product Security
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Whiteboard:	impact=low,public=20160915,reported=2...
Keywords:	Security

Duplicates:	1385659 (view as bug list)
Depends On:	1385676 1378666 1385674 1385675
Blocks:	1376684 1385672
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Reported:	2016-09-20 23:33 EDT by Doran Moppert
Modified:	2017-03-07 18:57 EST (History)
CC List:	7 users (show)

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Last Closed:	2016-09-22 23:20:52 EDT
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Description Doran Moppert 2016-09-20 23:33:17 EDT

Miscalculations in the safe_fprintf() function meant that the 
buffer allocated for decoding could be overflowed by crafted 
Unicode filenames.

Disclosed on oss-security:

http://seclists.org/oss-sec/2016/q3/516

Upstream issue:

https://github.com/libarchive/libarchive/issues/767

Upstream fix:

https://github.com/libarchive/libarchive/commit/e37b620f

Comment 1 Doran Moppert 2016-09-21 23:58:40 EDT

This only affects the bsdtar utility, libraries and applications linked against libarchive are not affected by this flaw.

Compiling with -fstack-protector-strong (as is the case in RHEL & Fedora) mitigates any code execution vector here.  In any case, the overflowed bytes are limited to ASCII octal escapes so even without these protections an attacker would need to be incredibly lucky to achieve more than a crash.

Comment 2 Doran Moppert 2016-09-22 23:15:31 EDT

Created libarchive tracking bugs for this issue:

Affects: fedora-all [bug 1378666]

Comment 3 Doran Moppert 2016-09-22 23:18:27 EDT

Statement:

Red Hat Product Security has rated this issue as having Low security impact. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.

Comment 4 Doran Moppert 2016-10-18 00:30:54 EDT

*** Bug 1385659 has been marked as a duplicate of this bug. ***

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