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
Alias: CVE-2017-12132
Product: Security Response
Classification: Other
Component: vulnerability   
(Show other bugs)
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Whiteboard: impact=low,public=20170407,reported=2...
Keywords: Security
Depends On: 1477530 1487063
Blocks: 1477532
TreeView+ depends on / blocked
Reported: 2017-08-02 10:56 UTC by Adam Mariš
Modified: 2018-04-10 08:21 UTC (History)
14 users (show)

Fixed In Version: glibc 2.26
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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 08:21 UTC

Description Adam Mariš 2017-08-02 10:56:00 UTC
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:


Comment 1 Adam Mariš 2017-08-02 10:56:32 UTC
Created glibc tracking bugs for this issue:

Affects: fedora-all [bug 1477530]

Comment 3 Huzaifa S. Sidhpurwala 2017-08-31 09:20:11 UTC

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 08:21:05 UTC
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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