Bug 1549961 – CVE-2018-5733 dhcp: Reference count overflow in dhcpd allows denial of service

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Bug 1549961 - (CVE-2018-5733) CVE-2018-5733 dhcp: Reference count overflow in dhcpd allows denial of service

Summary:	CVE-2018-5733 dhcp: Reference count overflow in dhcpd allows denial of service

Status:	CLOSED ERRATA

Aliases:	CVE-2018-5733

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

Priority	medium Severity medium
Target Milestone:	---
Target Release:	---
Assigned To:	Red Hat Product Security
QA Contact:
Docs Contact:

URL:
Whiteboard:	impact=moderate,public=20180228,repor...
Keywords:	Security

Depends On:	1549999 1550000 1550084 1550085 1550246 1550249
Blocks:	1549964
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Reported:	2018-02-28 02:32 EST by Adam Mariš
Modified:	2018-03-19 06:17 EDT (History)
CC List:	9 users (show)

See Also:
Fixed In Version:	dhcp 4.1-ESV-R15-P1, dhcp 4.3.6-P1, dhcp 4.4.1
Doc Type:	If docs needed, set a value
Doc Text:	A denial of service flaw was found in the way dhcpd handled reference counting when processing client requests. A malicious DHCP client could use this flaw to trigger a reference count overflow on the server side, potentially causing dhcpd to crash, by sending large amounts of traffic.
Story Points:	---
Clone Of:
Environment:
Last Closed:	2018-03-13 05:03:22 EDT
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

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External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHSA-2018:0469	normal	SHIPPED_LIVE	Important: dhcp security update	2018-03-09 10:09:18 EST
Red Hat Product Errata	RHSA-2018:0483	normal	SHIPPED_LIVE	Important: dhcp security update	2018-03-12 19:03:59 EDT

Groups: None (edit)

Description Adam Mariš 2018-02-28 02:32:47 EST

A malicious client which is allowed to send very large amounts of traffic (billions of packets) to a DHCP server can eventually overflow a 32-bit reference counter, potentially causing dhcpd to crash.

Versions of DHCP affected: 4.1.0 -> 4.1-ESV-R15, 4.2.0 -> 4.2.8, 4.3.0 -> 4.3.6, 4.4.0

Comment 1 Adam Mariš 2018-02-28 02:32:50 EST

Acknowledgments:

Name: ISC
Upstream: Felix Wilhelm (Google)

Comment 5 Tomas Hoger 2018-02-28 15:31:16 EST

Public now via upstream advisory.

External References:

https://kb.isc.org/article/AA-01567

Comment 6 Tomas Hoger 2018-02-28 15:31:55 EST

Created dhcp tracking bugs for this issue:

Affects: fedora-all [bug 1550246]

Comment 8 Tomas Hoger 2018-03-01 07:40:22 EST

Upstream commit:

https://source.isc.org/cgi-bin/gitweb.cgi?p=dhcp.git;a=commitdiff;h=197b26f25309f947b97a83b8fdfc414b767798f8

Upstream bug (not public):

https://bugs.isc.org/Public/Bug/Display.html?id=47140

Comment 9 errata-xmlrpc 2018-03-09 05:06:11 EST

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6

Via RHSA-2018:0469 https://access.redhat.com/errata/RHSA-2018:0469

Comment 10 errata-xmlrpc 2018-03-12 14:46:39 EDT

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2018:0483 https://access.redhat.com/errata/RHSA-2018:0483

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