Bug 1477529 – CVE-2017-12132 glibc: Fragmentation attacks possible when EDNS0 is enabled

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Bug 1477529 - (CVE-2017-12132) CVE-2017-12132 glibc: Fragmentation attacks possible when EDNS0 is enabled

Summary:	CVE-2017-12132 glibc: Fragmentation attacks possible when EDNS0 is enabled

Status:	NEW

Aliases:	CVE-2017-12132

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

Priority	low Severity low
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Target Release:	---
Assigned To:	Red Hat Product Security
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URL:
Whiteboard:	impact=low,public=20170407,reported=2...
Keywords:	Security

Depends On:	1477530 1487063
Blocks:	1477532
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Reported:	2017-08-02 06:56 EDT by Adam Mariš
Modified:	2018-04-10 04:21 EDT (History)
CC List:	14 users (show)

See Also:
Fixed In Version:	glibc 2.26
Doc Type:	If docs needed, set a value
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RHEL 7.3 requirements from Atomic Host:
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External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHSA-2018:0805	None	None	None	2018-04-10 04:21 EDT

Groups: None (edit)

Description Adam Mariš 2017-08-02 06:56:00 EDT

The DNS stub resolver in the GNU C Library (aka glibc or libc6) before version 2.26, when EDNS support is enabled, will solicit large UDP responses from name servers, potentially simplifying off-path DNS spoofing attacks due to IP fragmentation.

Upstream bug:

https://sourceware.org/bugzilla/show_bug.cgi?id=21361

Comment 1 Adam Mariš 2017-08-02 06:56:32 EDT

Created glibc tracking bugs for this issue:

Affects: fedora-all [bug 1477530]

Comment 3 Huzaifa S. Sidhpurwala 2017-08-31 05:20:11 EDT

Statement:

This issue only affects systems which use a remote recursive resolver and enable EDNS0, either with the “edns0” option in /etc/resolv.conf, or using the RES_USE_EDNS0 or RES_USE_DNSSEC resolver flags. The underlying issue affects recursive resolvers such as BIND and Unbound as well, and has to be fixed separately there.

Comment 4 errata-xmlrpc 2018-04-10 04:21:05 EDT

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2018:0805 https://access.redhat.com/errata/RHSA-2018:0805

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